LU-15068 ptlrpc: Do not unlink difficult reply until sent

[fs/lustre-release.git] / lustre / include / lustre_net.h

/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2010, 2017, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 */
/** \defgroup PtlRPC Portal RPC and networking module.
 *
 * PortalRPC is the layer used by rest of lustre code to achieve network
 * communications: establish connections with corresponding export and import
 * states, listen for a service, send and receive RPCs.
 * PortalRPC also includes base recovery framework: packet resending and
 * replaying, reconnections, pinger.
 *
 * PortalRPC utilizes LNet as its transport layer.
 *
 * @{
 */


#ifndef _LUSTRE_NET_H
#define _LUSTRE_NET_H

/** \defgroup net net
 *
 * @{
 */
#include <linux/kobject.h>
#include <linux/rhashtable.h>
#include <linux/uio.h>
#include <libcfs/libcfs.h>
#include <lnet/api.h>
#include <lnet/lib-types.h>
#include <uapi/linux/lnet/nidstr.h>
#include <uapi/linux/lustre/lustre_idl.h>
#include <lustre_ha.h>
#include <lustre_sec.h>
#include <lustre_import.h>
#include <lprocfs_status.h>
#include <lu_object.h>
#include <lustre_req_layout.h>
#include <obd_support.h>
#include <uapi/linux/lustre/lustre_ver.h>

/* MD flags we _always_ use */
#define PTLRPC_MD_OPTIONS  0

/**
 * log2 max # of bulk operations in one request: 2=4MB/RPC, 5=32MB/RPC, ...
 * In order for the client and server to properly negotiate the maximum
 * possible transfer size, PTLRPC_BULK_OPS_COUNT must be a power-of-two
 * value.  The client is free to limit the actual RPC size for any bulk
 * transfer via cl_max_pages_per_rpc to some non-power-of-two value.
 * NOTE: This is limited to 16 (=64GB RPCs) by IOOBJ_MAX_BRW_BITS. */
#define PTLRPC_BULK_OPS_BITS    6
#if PTLRPC_BULK_OPS_BITS > 16
#error "More than 65536 BRW RPCs not allowed by IOOBJ_MAX_BRW_BITS."
#endif
#define PTLRPC_BULK_OPS_COUNT   (1U << PTLRPC_BULK_OPS_BITS)
/**
 * PTLRPC_BULK_OPS_MASK is for the convenience of the client only, and
 * should not be used on the server at all.  Otherwise, it imposes a
 * protocol limitation on the maximum RPC size that can be used by any
 * RPC sent to that server in the future.  Instead, the server should
 * use the negotiated per-client ocd_brw_size to determine the bulk
 * RPC count. */
#define PTLRPC_BULK_OPS_MASK    (~((__u64)PTLRPC_BULK_OPS_COUNT - 1))

/**
 * Define maxima for bulk I/O.
 *
 * A single PTLRPC BRW request is sent via up to PTLRPC_BULK_OPS_COUNT
 * of LNET_MTU sized RDMA transfers.  Clients and servers negotiate the
 * currently supported maximum between peers at connect via ocd_brw_size.
 */
#define PTLRPC_MAX_BRW_BITS     (LNET_MTU_BITS + PTLRPC_BULK_OPS_BITS)
#define PTLRPC_MAX_BRW_SIZE     (1U << PTLRPC_MAX_BRW_BITS)
#define PTLRPC_MAX_BRW_PAGES    (PTLRPC_MAX_BRW_SIZE >> PAGE_SHIFT)

#define ONE_MB_BRW_SIZE         (1U << LNET_MTU_BITS)
#define MD_MAX_BRW_SIZE         (1U << LNET_MTU_BITS)
#define MD_MAX_BRW_PAGES        (MD_MAX_BRW_SIZE >> PAGE_SHIFT)
#define DT_MAX_BRW_SIZE         PTLRPC_MAX_BRW_SIZE
#define DT_DEF_BRW_SIZE         (4 * ONE_MB_BRW_SIZE)
#define DT_MAX_BRW_PAGES        (DT_MAX_BRW_SIZE >> PAGE_SHIFT)
#define OFD_MAX_BRW_SIZE        (1U << LNET_MTU_BITS)

/* When PAGE_SIZE is a constant, we can check our arithmetic here with cpp! */
#if ((PTLRPC_MAX_BRW_PAGES & (PTLRPC_MAX_BRW_PAGES - 1)) != 0)
# error "PTLRPC_MAX_BRW_PAGES isn't a power of two"
#endif
#if (PTLRPC_MAX_BRW_SIZE != (PTLRPC_MAX_BRW_PAGES * PAGE_SIZE))
# error "PTLRPC_MAX_BRW_SIZE isn't PTLRPC_MAX_BRW_PAGES * PAGE_SIZE"
#endif
#if (PTLRPC_MAX_BRW_SIZE > LNET_MTU * PTLRPC_BULK_OPS_COUNT)
# error "PTLRPC_MAX_BRW_SIZE too big"
#endif
#if (PTLRPC_MAX_BRW_PAGES > LNET_MAX_IOV * PTLRPC_BULK_OPS_COUNT)
# error "PTLRPC_MAX_BRW_PAGES too big"
#endif

#define PTLRPC_NTHRS_INIT       2

/**
 * Buffer Constants
 *
 * Constants determine how memory is used to buffer incoming service requests.
 *
 * ?_NBUFS              # buffers to allocate when growing the pool
 * ?_BUFSIZE            # bytes in a single request buffer
 * ?_MAXREQSIZE         # maximum request service will receive
 *
 * When fewer than ?_NBUFS/2 buffers are posted for receive, another chunk
 * of ?_NBUFS is added to the pool.
 *
 * Messages larger than ?_MAXREQSIZE are dropped.  Request buffers are
 * considered full when less than ?_MAXREQSIZE is left in them.
 */
/**
 * Thread Constants
 *
 * Constants determine how threads are created for ptlrpc service.
 *
 * ?_NTHRS_INIT         # threads to create for each service partition on
 *                        initializing. If it's non-affinity service and
 *                        there is only one partition, it's the overall #
 *                        threads for the service while initializing.
 * ?_NTHRS_BASE         # threads should be created at least for each
 *                        ptlrpc partition to keep the service healthy.
 *                        It's the low-water mark of threads upper-limit
 *                        for each partition.
 * ?_THR_FACTOR         # threads can be added on threads upper-limit for
 *                        each CPU core. This factor is only for reference,
 *                        we might decrease value of factor if number of cores
 *                        per CPT is above a limit.
 * ?_NTHRS_MAX          # overall threads can be created for a service,
 *                        it's a soft limit because if service is running
 *                        on machine with hundreds of cores and tens of
 *                        CPU partitions, we need to guarantee each partition
 *                        has ?_NTHRS_BASE threads, which means total threads
 *                        will be ?_NTHRS_BASE * number_of_cpts which can
 *                        exceed ?_NTHRS_MAX.
 *
 * Examples
 *
 * #define MDS_NTHRS_INIT       2
 * #define MDS_NTHRS_BASE       64
 * #define MDS_NTHRS_FACTOR     8
 * #define MDS_NTHRS_MAX        1024
 *
 * Example 1):
 * ---------------------------------------------------------------------
 * Server(A) has 16 cores, user configured it to 4 partitions so each
 * partition has 4 cores, then actual number of service threads on each
 * partition is:
 *     MDS_NTHRS_BASE(64) + cores(4) * MDS_NTHRS_FACTOR(8) = 96
 *
 * Total number of threads for the service is:
 *     96 * partitions(4) = 384
 *
 * Example 2):
 * ---------------------------------------------------------------------
 * Server(B) has 32 cores, user configured it to 4 partitions so each
 * partition has 8 cores, then actual number of service threads on each
 * partition is:
 *     MDS_NTHRS_BASE(64) + cores(8) * MDS_NTHRS_FACTOR(8) = 128
 *
 * Total number of threads for the service is:
 *     128 * partitions(4) = 512
 *
 * Example 3):
 * ---------------------------------------------------------------------
 * Server(B) has 96 cores, user configured it to 8 partitions so each
 * partition has 12 cores, then actual number of service threads on each
 * partition is:
 *     MDS_NTHRS_BASE(64) + cores(12) * MDS_NTHRS_FACTOR(8) = 160
 *
 * Total number of threads for the service is:
 *     160 * partitions(8) = 1280
 *
 * However, it's above the soft limit MDS_NTHRS_MAX, so we choose this number
 * as upper limit of threads number for each partition:
 *     MDS_NTHRS_MAX(1024) / partitions(8) = 128
 *
 * Example 4):
 * ---------------------------------------------------------------------
 * Server(C) have a thousand of cores and user configured it to 32 partitions
 *     MDS_NTHRS_BASE(64) * 32 = 2048
 *
 * which is already above soft limit MDS_NTHRS_MAX(1024), but we still need
 * to guarantee that each partition has at least MDS_NTHRS_BASE(64) threads
 * to keep service healthy, so total number of threads will just be 2048.
 *
 * NB: we don't suggest to choose server with that many cores because backend
 *     filesystem itself, buffer cache, or underlying network stack might
 *     have some SMP scalability issues at that large scale.
 *
 *     If user already has a fat machine with hundreds or thousands of cores,
 *     there are two choices for configuration:
 *     a) create CPU table from subset of all CPUs and run Lustre on
 *        top of this subset
 *     b) bind service threads on a few partitions, see modparameters of
 *        MDS and OSS for details
*
 * NB: these calculations (and examples below) are simplified to help
 *     understanding, the real implementation is a little more complex,
 *     please see ptlrpc_server_nthreads_check() for details.
 *
 */

 /*
  * LDLM threads constants:
  *
  * Given 8 as factor and 24 as base threads number
  *
  * example 1)
  * On 4-core machine we will have 24 + 8 * 4 = 56 threads.
  *
  * example 2)
  * On 8-core machine with 2 partitions we will have 24 + 4 * 8 = 56
  * threads for each partition and total threads number will be 112.
  *
  * example 3)
  * On 64-core machine with 8 partitions we will need LDLM_NTHRS_BASE(24)
  * threads for each partition to keep service healthy, so total threads
  * number should be 24 * 8 = 192.
  *
  * So with these constants, threads number will be at the similar level
  * of old versions, unless target machine has over a hundred cores
  */
#define LDLM_THR_FACTOR         8
#define LDLM_NTHRS_INIT         PTLRPC_NTHRS_INIT
#define LDLM_NTHRS_BASE         24
#define LDLM_NTHRS_MAX          (num_online_cpus() == 1 ? 64 : 128)

#define LDLM_BL_THREADS   LDLM_NTHRS_AUTO_INIT
#define LDLM_CLIENT_NBUFS 1
#define LDLM_SERVER_NBUFS 64
#define LDLM_BUFSIZE      (8 * 1024)
#define LDLM_MAXREQSIZE   (5 * 1024)
#define LDLM_MAXREPSIZE   (1024)

 /*
  * MDS threads constants:
  *
  * Please see examples in "Thread Constants", MDS threads number will be at
  * the comparable level of old versions, unless the server has many cores.
  */
#ifndef MDS_MAX_THREADS
#define MDS_MAX_THREADS         1024
#define MDS_MAX_OTHR_THREADS    256

#else /* MDS_MAX_THREADS */
#if MDS_MAX_THREADS < PTLRPC_NTHRS_INIT
#undef MDS_MAX_THREADS
#define MDS_MAX_THREADS PTLRPC_NTHRS_INIT
#endif
#define MDS_MAX_OTHR_THREADS    max(PTLRPC_NTHRS_INIT, MDS_MAX_THREADS / 2)
#endif

/* default service */
#define MDS_THR_FACTOR          8
#define MDS_NTHRS_INIT          PTLRPC_NTHRS_INIT
#define MDS_NTHRS_MAX           MDS_MAX_THREADS
#define MDS_NTHRS_BASE          min(64, MDS_NTHRS_MAX)

/* read-page service */
#define MDS_RDPG_THR_FACTOR     4
#define MDS_RDPG_NTHRS_INIT     PTLRPC_NTHRS_INIT
#define MDS_RDPG_NTHRS_MAX      MDS_MAX_OTHR_THREADS
#define MDS_RDPG_NTHRS_BASE     min(48, MDS_RDPG_NTHRS_MAX)

/* these should be removed when we remove setattr service in the future */
#define MDS_SETA_THR_FACTOR     4
#define MDS_SETA_NTHRS_INIT     PTLRPC_NTHRS_INIT
#define MDS_SETA_NTHRS_MAX      MDS_MAX_OTHR_THREADS
#define MDS_SETA_NTHRS_BASE     min(48, MDS_SETA_NTHRS_MAX)

/* non-affinity threads */
#define MDS_OTHR_NTHRS_INIT     PTLRPC_NTHRS_INIT
#define MDS_OTHR_NTHRS_MAX      MDS_MAX_OTHR_THREADS

#define MDS_NBUFS               64

/**
 * Assume file name length = FNAME_MAX = 256 (true for ext3).
 *        path name length = PATH_MAX = 4096
 *        LOV MD size max  = EA_MAX = 24 * 2000
 *              (NB: 24 is size of lov_ost_data)
 *        LOV LOGCOOKIE size max = 32 * 2000
 *              (NB: 32 is size of llog_cookie)
 * symlink:  FNAME_MAX + PATH_MAX  <- largest
 * link:     FNAME_MAX + PATH_MAX  (mds_rec_link < mds_rec_create)
 * rename:   FNAME_MAX + FNAME_MAX
 * open:     FNAME_MAX + EA_MAX
 *
 * MDS_MAXREQSIZE ~= 4736 bytes =
 * lustre_msg + ldlm_request + mdt_body + mds_rec_create + FNAME_MAX + PATH_MAX
 * MDS_MAXREPSIZE ~= 8300 bytes = lustre_msg + llog_header
 *
 * Realistic size is about 512 bytes (20 character name + 128 char symlink),
 * except in the open case where there are a large number of OSTs in a LOV.
 */
#define MDS_MAXREQSIZE          (5 * 1024)      /* >= 4736 */
#define MDS_MAXREPSIZE          (9 * 1024)      /* >= 8300 */

/**
 * MDS incoming request with LOV EA
 * 24 = sizeof(struct lov_ost_data), i.e: replay of opencreate
 */
#define MDS_LOV_MAXREQSIZE      max(MDS_MAXREQSIZE, \
                                    362 + LOV_MAX_STRIPE_COUNT * 24)
/**
 * MDS outgoing reply with LOV EA
 *
 * NB: max reply size Lustre 2.4+ client can get from old MDS is:
 * LOV_MAX_STRIPE_COUNT * (llog_cookie + lov_ost_data) + extra bytes
 *
 * but 2.4 or later MDS will never send reply with llog_cookie to any
 * version client. This macro is defined for server side reply buffer size.
 */
#define MDS_LOV_MAXREPSIZE      MDS_LOV_MAXREQSIZE

/**
 * This is the size of a maximum REINT_SETXATTR request:
 *
 *   lustre_msg          56 (32 + 4 x 5 + 4)
 *   ptlrpc_body        184
 *   mdt_rec_setxattr   136
 *   lustre_capa        120
 *   name               256 (XATTR_NAME_MAX)
 *   value            65536 (XATTR_SIZE_MAX)
 */
#define MDS_EA_MAXREQSIZE       66288

/**
 * These are the maximum request and reply sizes (rounded up to 1 KB
 * boundaries) for the "regular" MDS_REQUEST_PORTAL and MDS_REPLY_PORTAL.
 */
#define MDS_REG_MAXREQSIZE      (((max(MDS_EA_MAXREQSIZE, \
                                       MDS_LOV_MAXREQSIZE) + 1023) >> 10) << 10)
#define MDS_REG_MAXREPSIZE      MDS_REG_MAXREQSIZE

/**
 * The update request includes all of updates from the create, which might
 * include linkea (4K maxim), together with other updates, we set it to 1000K:
 * lustre_msg + ptlrpc_body + OUT_UPDATE_BUFFER_SIZE_MAX
 */
#define OUT_MAXREQSIZE  (1000 * 1024)
#define OUT_MAXREPSIZE  MDS_MAXREPSIZE

/** MDS_BUFSIZE = max_reqsize (w/o LOV EA) + max sptlrpc payload size */
#define MDS_BUFSIZE             max(MDS_MAXREQSIZE + SPTLRPC_MAX_PAYLOAD, \
                                    8 * 1024)

/**
 * MDS_REG_BUFSIZE should at least be MDS_REG_MAXREQSIZE + SPTLRPC_MAX_PAYLOAD.
 * However, we need to allocate a much larger buffer for it because LNet
 * requires each MD(rqbd) has at least MDS_REQ_MAXREQSIZE bytes left to avoid
 * dropping of maximum-sized incoming request.  So if MDS_REG_BUFSIZE is only a
 * little larger than MDS_REG_MAXREQSIZE, then it can only fit in one request
 * even there are about MDS_REG_MAX_REQSIZE bytes left in a rqbd, and memory
 * utilization is very low.
 *
 * In the meanwhile, size of rqbd can't be too large, because rqbd can't be
 * reused until all requests fit in it have been processed and released,
 * which means one long blocked request can prevent the rqbd be reused.
 * Now we set request buffer size to 160 KB, so even each rqbd is unlinked
 * from LNet with unused 65 KB, buffer utilization will be about 59%.
 * Please check LU-2432 for details.
 */
#define MDS_REG_BUFSIZE         max(MDS_REG_MAXREQSIZE + SPTLRPC_MAX_PAYLOAD, \
                                    160 * 1024)

/**
 * OUT_BUFSIZE = max_out_reqsize + max sptlrpc payload (~1K) which is
 * about 10K, for the same reason as MDS_REG_BUFSIZE, we also give some
 * extra bytes to each request buffer to improve buffer utilization rate.
  */
#define OUT_BUFSIZE             max(OUT_MAXREQSIZE + SPTLRPC_MAX_PAYLOAD, \
                                    24 * 1024)

/** FLD_MAXREQSIZE == lustre_msg + __u32 padding + ptlrpc_body + opc */
#define FLD_MAXREQSIZE  (160)

/** FLD_MAXREPSIZE == lustre_msg + ptlrpc_body */
#define FLD_MAXREPSIZE  (152)
#define FLD_BUFSIZE     (1 << 12)

/**
 * SEQ_MAXREQSIZE == lustre_msg + __u32 padding + ptlrpc_body + opc + lu_range +
 * __u32 padding */
#define SEQ_MAXREQSIZE  (160)

/** SEQ_MAXREPSIZE == lustre_msg + ptlrpc_body + lu_range */
#define SEQ_MAXREPSIZE  (152)
#define SEQ_BUFSIZE     (1 << 12)

/** MGS threads must be >= 3, see bug 22458 comment #28 */
#define MGS_NTHRS_INIT  (PTLRPC_NTHRS_INIT + 1)
#define MGS_NTHRS_MAX   32

#define MGS_NBUFS       64
#define MGS_BUFSIZE     (8 * 1024)
#define MGS_MAXREQSIZE  (7 * 1024)
#define MGS_MAXREPSIZE  (9 * 1024)

 /*
  * OSS threads constants:
  *
  * Given 8 as factor and 64 as base threads number
  *
  * example 1):
  * On 8-core server configured to 2 partitions, we will have
  * 64 + 8 * 4 = 96 threads for each partition, 192 total threads.
  *
  * example 2):
  * On 32-core machine configured to 4 partitions, we will have
  * 64 + 8 * 8 = 112 threads for each partition, so total threads number
  * will be 112 * 4 = 448.
  *
  * example 3):
  * On 64-core machine configured to 4 partitions, we will have
  * 64 + 16 * 8 = 192 threads for each partition, so total threads number
  * will be 192 * 4 = 768 which is above limit OSS_NTHRS_MAX(512), so we
  * cut off the value to OSS_NTHRS_MAX(512) / 4 which is 128 threads
  * for each partition.
  *
  * So we can see that with these constants, threads number wil be at the
  * similar level of old versions, unless the server has many cores.
  */
 /* depress threads factor for VM with small memory size */
#define OSS_THR_FACTOR          min_t(int, 8, \
                                NUM_CACHEPAGES >> (28 - PAGE_SHIFT))
#define OSS_NTHRS_INIT          (PTLRPC_NTHRS_INIT + 1)
#define OSS_NTHRS_BASE          64

/* threads for handling "create" request */
#define OSS_CR_THR_FACTOR       1
#define OSS_CR_NTHRS_INIT       PTLRPC_NTHRS_INIT
#define OSS_CR_NTHRS_BASE       8
#define OSS_CR_NTHRS_MAX        64

/**
 * OST_IO_MAXREQSIZE ~=
 *      lustre_msg + ptlrpc_body + obdo + obd_ioobj +
 *      DT_MAX_BRW_PAGES * niobuf_remote
 *
 * - single object with 16 pages is 512 bytes
 * - OST_IO_MAXREQSIZE must be at least 1 niobuf per page of data
 * - Must be a multiple of 1024
 * - should allow a reasonably large SHORT_IO_BYTES size (64KB)
 */
#define _OST_MAXREQSIZE_BASE ((unsigned long)(sizeof(struct lustre_msg)   + \
                             /* lm_buflens */ sizeof(__u32) * 4           + \
                                              sizeof(struct ptlrpc_body)  + \
                                              sizeof(struct obdo)         + \
                                              sizeof(struct obd_ioobj)    + \
                                              sizeof(struct niobuf_remote)))
#define _OST_MAXREQSIZE_SUM ((unsigned long)(_OST_MAXREQSIZE_BASE         + \
                                             sizeof(struct niobuf_remote) * \
                                             DT_MAX_BRW_PAGES))
/**
 * FIEMAP request can be 4K+ for now
 */
#define OST_MAXREQSIZE          (16UL * 1024UL)
#define OST_IO_MAXREQSIZE       max(OST_MAXREQSIZE,                     \
                                   ((_OST_MAXREQSIZE_SUM - 1) |         \
                                    (1024UL - 1)) + 1)
/* Safe estimate of free space in standard RPC, provides upper limit for # of
 * bytes of i/o to pack in RPC (skipping bulk transfer). */
#define OST_MAX_SHORT_IO_BYTES  ((OST_IO_MAXREQSIZE - _OST_MAXREQSIZE_BASE) & \
                                 PAGE_MASK)

/* Actual size used for short i/o buffer.  Calculation means this:
 * At least one page (for large PAGE_SIZE), or 16 KiB, but not more
 * than the available space aligned to a page boundary. */
#define OBD_DEF_SHORT_IO_BYTES  min(max(PAGE_SIZE, 16UL * 1024UL), \
                                    OST_MAX_SHORT_IO_BYTES)

#define OST_MAXREPSIZE          (9 * 1024)
#define OST_IO_MAXREPSIZE       OST_MAXREPSIZE

#define OST_NBUFS               64
/** OST_BUFSIZE = max_reqsize + max sptlrpc payload size */
#define OST_BUFSIZE             max_t(int, OST_MAXREQSIZE + 1024, 32 * 1024)
/**
 * OST_IO_MAXREQSIZE is 18K, giving extra 46K can increase buffer utilization
 * rate of request buffer, please check comment of MDS_LOV_BUFSIZE for details.
 */
#define OST_IO_BUFSIZE          max_t(int, OST_IO_MAXREQSIZE + 1024, 64 * 1024)

/* Macro to hide a typecast and BUILD_BUG. */
#define ptlrpc_req_async_args(_var, req) ({                             \
                BUILD_BUG_ON(sizeof(*_var) > sizeof(req->rq_async_args)); \
                (typeof(_var))&req->rq_async_args;                      \
        })

struct ptlrpc_replay_async_args {
        int             praa_old_state;
        int             praa_old_status;
};

/**
 * Structure to single define portal connection.
 */
struct ptlrpc_connection {
        /** linkage for connections hash table */
        struct rhash_head       c_hash;
        /** Our own lnet nid for this connection */
        lnet_nid_t              c_self;
        /** Remote side nid for this connection */
        struct lnet_process_id       c_peer;
        /** UUID of the other side */
        struct obd_uuid         c_remote_uuid;
        /** reference counter for this connection */
        atomic_t            c_refcount;
};

/** Client definition for PortalRPC */
struct ptlrpc_client {
        /** What lnet portal does this client send messages to by default */
        __u32                   cli_request_portal;
        /** What portal do we expect replies on */
        __u32                   cli_reply_portal;
        /** Name of the client */
        const char              *cli_name;
};

/** state flags of requests */
/* XXX only ones left are those used by the bulk descs as well! */
#define PTL_RPC_FL_INTR         BIT(0)  /* reply wait was interrupted by user */
#define PTL_RPC_FL_TIMEOUT      BIT(7)  /* request timed out waiting for reply */

#define REQ_MAX_ACK_LOCKS 8

union ptlrpc_async_args {
        /**
         * Scratchpad for passing args to completion interpreter. Users
         * cast to the struct of their choosing, and BUILD_BUG_ON that this is
         * big enough.  For _tons_ of context, OBD_ALLOC a struct and store
         * a pointer to it here.  The pointer_arg ensures this struct is at
         * least big enough for that.
         */
        void    *pointer_arg[11];
        __u64   space[7];
};

struct ptlrpc_request_set;
typedef int (*set_producer_func)(struct ptlrpc_request_set *, void *);

/**
 * Definition of request set structure.
 * Request set is a list of requests (not necessary to the same target) that
 * once populated with RPCs could be sent in parallel.
 * There are two kinds of request sets. General purpose and with dedicated
 * serving thread. Example of the latter is ptlrpcd set.
 * For general purpose sets once request set started sending it is impossible
 * to add new requests to such set.
 * Provides a way to call "completion callbacks" when all requests in the set
 * returned.
 */
struct ptlrpc_request_set {
        atomic_t                set_refcount;
        /** number of in queue requests */
        atomic_t                set_new_count;
        /** number of uncompleted requests */
        atomic_t                set_remaining;
        /** wait queue to wait on for request events */
        wait_queue_head_t       set_waitq;
        /** List of requests in the set */
        struct list_head        set_requests;
        /**
         * Lock for \a set_new_requests manipulations
         * locked so that any old caller can communicate requests to
         * the set holder who can then fold them into the lock-free set
         */
        spinlock_t              set_new_req_lock;
        /** List of new yet unsent requests. Only used with ptlrpcd now. */
        struct list_head        set_new_requests;

        /** rq_status of requests that have been freed already */
        int                     set_rc;
        /** Additional fields used by the flow control extension */
        /** Maximum number of RPCs in flight */
        int                     set_max_inflight;
        /** Callback function used to generate RPCs */
        set_producer_func       set_producer;
        /** opaq argument passed to the producer callback */
        void                    *set_producer_arg;
        unsigned int             set_allow_intr:1;
};

struct ptlrpc_bulk_desc;
struct ptlrpc_service_part;
struct ptlrpc_service;

/**
 * ptlrpc callback & work item stuff
 */
struct ptlrpc_cb_id {
        void (*cbid_fn)(struct lnet_event *ev); /* specific callback fn */
        void *cbid_arg;                         /* additional arg */
};

/** Maximum number of locks to fit into reply state */
#define RS_MAX_LOCKS 8
#define RS_DEBUG     0

/**
 * Structure to define reply state on the server
 * Reply state holds various reply message information. Also for "difficult"
 * replies (rep-ack case) we store the state after sending reply and wait
 * for the client to acknowledge the reception. In these cases locks could be
 * added to the state for replay/failover consistency guarantees.
 */
struct ptlrpc_reply_state {
        /** Callback description */
        struct ptlrpc_cb_id     rs_cb_id;
        /** Linkage for list of all reply states in a system */
        struct list_head        rs_list;
        /** Linkage for list of all reply states on same export */
        struct list_head        rs_exp_list;
        /** Linkage for list of all reply states for same obd */
        struct list_head        rs_obd_list;
#if RS_DEBUG
        struct list_head        rs_debug_list;
#endif
        /** A spinlock to protect the reply state flags */
        spinlock_t              rs_lock;
        /** Reply state flags */
        unsigned long           rs_difficult:1;     /* ACK/commit stuff */
        unsigned long           rs_no_ack:1;    /* no ACK, even for
                                                  difficult requests */
        unsigned long           rs_scheduled:1;     /* being handled? */
        unsigned long           rs_scheduled_ever:1;/* any schedule attempts? */
        unsigned long           rs_handled:1;  /* been handled yet? */
        unsigned long           rs_sent:1;   /* Got LNET_EVENT_SEND? */
        unsigned long           rs_unlinked:1; /* Reply MD unlinked? */
        unsigned long           rs_prealloc:1; /* rs from prealloc list */
        unsigned long           rs_committed:1;/* the transaction was committed
                                                 and the rs was dispatched
                                                 by ptlrpc_commit_replies */
        unsigned long           rs_convert_lock:1; /* need to convert saved
                                                    * locks to COS mode */
        atomic_t                rs_refcount;    /* number of users */
        /** Number of locks awaiting client ACK */
        int                     rs_nlocks;

        /** Size of the state */
        int                     rs_size;
        /** opcode */
        __u32                   rs_opc;
        /** Transaction number */
        __u64                   rs_transno;
        /** xid */
        __u64                   rs_xid;
        struct obd_export       *rs_export;
        struct ptlrpc_service_part *rs_svcpt;
        /** Lnet metadata handle for the reply */
        struct lnet_handle_md   rs_md_h;

        /** Context for the sevice thread */
        struct ptlrpc_svc_ctx   *rs_svc_ctx;
        /** Reply buffer (actually sent to the client), encoded if needed */
        struct lustre_msg       *rs_repbuf;     /* wrapper */
        /** Size of the reply buffer */
        int                     rs_repbuf_len;  /* wrapper buf length */
        /** Size of the reply message */
        int                     rs_repdata_len; /* wrapper msg length */
        /**
         * Actual reply message. Its content is encrupted (if needed) to
         * produce reply buffer for actual sending. In simple case
         * of no network encryption we jus set \a rs_repbuf to \a rs_msg
         */
        struct lustre_msg       *rs_msg;        /* reply message */

        /** Handles of locks awaiting client reply ACK */
        struct lustre_handle    rs_locks[RS_MAX_LOCKS];
        /** Lock modes of locks in \a rs_locks */
        enum ldlm_mode          rs_modes[RS_MAX_LOCKS];
};

struct ptlrpc_thread;

/** RPC stages */
enum rq_phase {
        RQ_PHASE_NEW            = 0xebc0de00,
        RQ_PHASE_RPC            = 0xebc0de01,
        RQ_PHASE_BULK           = 0xebc0de02,
        RQ_PHASE_INTERPRET      = 0xebc0de03,
        RQ_PHASE_COMPLETE       = 0xebc0de04,
        RQ_PHASE_UNREG_RPC      = 0xebc0de05,
        RQ_PHASE_UNREG_BULK     = 0xebc0de06,
        RQ_PHASE_UNDEFINED      = 0xebc0de07
};

/** Type of request interpreter call-back */
typedef int (*ptlrpc_interpterer_t)(const struct lu_env *env,
                                    struct ptlrpc_request *req,
                                    void *arg, int rc);
/** Type of request resend call-back */
typedef void (*ptlrpc_resend_cb_t)(struct ptlrpc_request *req,
                                   void *arg);

/**
 * Definition of request pool structure.
 * The pool is used to store empty preallocated requests for the case
 * when we would actually need to send something without performing
 * any allocations (to avoid e.g. OOM).
 */
struct ptlrpc_request_pool {
        /** Locks the list */
        spinlock_t              prp_lock;
        /** list of ptlrpc_request structs */
        struct list_head        prp_req_list;
        /** Maximum message size that would fit into a rquest from this pool */
        int                     prp_rq_size;
        /** Function to allocate more requests for this pool */
        int (*prp_populate)(struct ptlrpc_request_pool *, int);
};

struct lu_context;
struct lu_env;

struct ldlm_lock;

#include <lustre_nrs.h>

/**
 * Basic request prioritization operations structure.
 * The whole idea is centered around locks and RPCs that might affect locks.
 * When a lock is contended we try to give priority to RPCs that might lead
 * to fastest release of that lock.
 * Currently only implemented for OSTs only in a way that makes all
 * IO and truncate RPCs that are coming from a locked region where a lock is
 * contended a priority over other requests.
 */
struct ptlrpc_hpreq_ops {
        /**
         * Check if the lock handle of the given lock is the same as
         * taken from the request.
         */
        int  (*hpreq_lock_match)(struct ptlrpc_request *, struct ldlm_lock *);
        /**
         * Check if the request is a high priority one.
         */
        int  (*hpreq_check)(struct ptlrpc_request *);
        /**
         * Called after the request has been handled.
         */
        void (*hpreq_fini)(struct ptlrpc_request *);
};

struct ptlrpc_cli_req {
        /** For bulk requests on client only: bulk descriptor */
        struct ptlrpc_bulk_desc         *cr_bulk;
        /** optional time limit for send attempts. This is a timeout
         *  not a timestamp so timeout_t (s32) is used instead of time64_t
         */
        timeout_t                        cr_delay_limit;
        /** time request was first queued */
        time64_t                         cr_queued_time;
        /** request sent in nanoseconds */
        ktime_t                          cr_sent_ns;
        /** time for request really sent out */
        time64_t                         cr_sent_out;
        /** when req reply unlink must finish. */
        time64_t                         cr_reply_deadline;
        /** when req bulk unlink must finish. */
        time64_t                         cr_bulk_deadline;
        /** when req unlink must finish. */
        time64_t                         cr_req_deadline;
        /** Portal to which this request would be sent */
        short                            cr_req_ptl;
        /** Portal where to wait for reply and where reply would be sent */
        short                            cr_rep_ptl;
        /** request resending number */
        unsigned int                     cr_resend_nr;
        /** What was import generation when this request was sent */
        int                              cr_imp_gen;
        enum lustre_imp_state            cr_send_state;
        /** Per-request waitq introduced by bug 21938 for recovery waiting */
        wait_queue_head_t                cr_set_waitq;
        /** Link item for request set lists */
        struct list_head                 cr_set_chain;
        /** link to waited ctx */
        struct list_head                 cr_ctx_chain;

        /** client's half ctx */
        struct ptlrpc_cli_ctx           *cr_cli_ctx;
        /** Link back to the request set */
        struct ptlrpc_request_set       *cr_set;
        /** outgoing request MD handle */
        struct lnet_handle_md            cr_req_md_h;
        /** request-out callback parameter */
        struct ptlrpc_cb_id              cr_req_cbid;
        /** incoming reply MD handle */
        struct lnet_handle_md            cr_reply_md_h;
        wait_queue_head_t                cr_reply_waitq;
        /** reply callback parameter */
        struct ptlrpc_cb_id              cr_reply_cbid;
        /** Async completion handler, called when reply is received */
        ptlrpc_interpterer_t             cr_reply_interp;
        /** Resend handler, called when request is resend to update RPC data */
        ptlrpc_resend_cb_t               cr_resend_cb;
        /** Async completion context */
        union ptlrpc_async_args          cr_async_args;
        /** Opaq data for replay and commit callbacks. */
        void                            *cr_cb_data;
        /** Link to the imp->imp_unreplied_list */
        struct list_head                 cr_unreplied_list;
        /**
         * Commit callback, called when request is committed and about to be
         * freed.
         */
        void (*cr_commit_cb)(struct ptlrpc_request *);
        /** Replay callback, called after request is replayed at recovery */
        void (*cr_replay_cb)(struct ptlrpc_request *);
};

/** client request member alias */
/* NB: these alias should NOT be used by any new code, instead they should
 * be removed step by step to avoid potential abuse */
#define rq_bulk                 rq_cli.cr_bulk
#define rq_delay_limit          rq_cli.cr_delay_limit
#define rq_queued_time          rq_cli.cr_queued_time
#define rq_sent_ns              rq_cli.cr_sent_ns
#define rq_real_sent            rq_cli.cr_sent_out
#define rq_reply_deadline       rq_cli.cr_reply_deadline
#define rq_bulk_deadline        rq_cli.cr_bulk_deadline
#define rq_req_deadline         rq_cli.cr_req_deadline
#define rq_nr_resend            rq_cli.cr_resend_nr
#define rq_request_portal       rq_cli.cr_req_ptl
#define rq_reply_portal         rq_cli.cr_rep_ptl
#define rq_import_generation    rq_cli.cr_imp_gen
#define rq_send_state           rq_cli.cr_send_state
#define rq_set_chain            rq_cli.cr_set_chain
#define rq_ctx_chain            rq_cli.cr_ctx_chain
#define rq_set                  rq_cli.cr_set
#define rq_set_waitq            rq_cli.cr_set_waitq
#define rq_cli_ctx              rq_cli.cr_cli_ctx
#define rq_req_md_h             rq_cli.cr_req_md_h
#define rq_req_cbid             rq_cli.cr_req_cbid
#define rq_reply_md_h           rq_cli.cr_reply_md_h
#define rq_reply_waitq          rq_cli.cr_reply_waitq
#define rq_reply_cbid           rq_cli.cr_reply_cbid
#define rq_interpret_reply      rq_cli.cr_reply_interp
#define rq_resend_cb            rq_cli.cr_resend_cb
#define rq_async_args           rq_cli.cr_async_args
#define rq_cb_data              rq_cli.cr_cb_data
#define rq_unreplied_list       rq_cli.cr_unreplied_list
#define rq_commit_cb            rq_cli.cr_commit_cb
#define rq_replay_cb            rq_cli.cr_replay_cb

struct ptlrpc_srv_req {
        /** initial thread servicing this request */
        struct ptlrpc_thread            *sr_svc_thread;
        /**
         * Server side list of incoming unserved requests sorted by arrival
         * time.  Traversed from time to time to notice about to expire
         * requests and sent back "early replies" to clients to let them
         * know server is alive and well, just very busy to service their
         * requests in time
         */
        struct list_head                 sr_timed_list;
        /** server-side per-export list */
        struct list_head                 sr_exp_list;
        /** server-side history, used for debuging purposes. */
        struct list_head                 sr_hist_list;
        /** history sequence # */
        __u64                            sr_hist_seq;
        /** the index of service's srv_at_array into which request is linked */
        __u32                            sr_at_index;
        /** authed uid */
        uid_t                            sr_auth_uid;
        /** authed uid mapped to */
        uid_t                            sr_auth_mapped_uid;
        /** RPC is generated from what part of Lustre */
        enum lustre_sec_part             sr_sp_from;
        /** request session context */
        struct lu_context                sr_ses;
        /** \addtogroup  nrs
         * @{
         */
        /** stub for NRS request */
        struct ptlrpc_nrs_request        sr_nrq;
        /** @} nrs */
        /** request arrival time */
        struct timespec64                sr_arrival_time;
        /** server's half ctx */
        struct ptlrpc_svc_ctx           *sr_svc_ctx;
        /** (server side), pointed directly into req buffer */
        struct ptlrpc_user_desc         *sr_user_desc;
        /** separated reply state, may be vmalloc'd */
        struct ptlrpc_reply_state       *sr_reply_state;
        /** server-side hp handlers */
        struct ptlrpc_hpreq_ops         *sr_ops;
        /** incoming request buffer */
        struct ptlrpc_request_buffer_desc *sr_rqbd;
};

/** server request member alias */
/* NB: these alias should NOT be used by any new code, instead they should
 * be removed step by step to avoid potential abuse */
#define rq_svc_thread           rq_srv.sr_svc_thread
#define rq_timed_list           rq_srv.sr_timed_list
#define rq_exp_list             rq_srv.sr_exp_list
#define rq_history_list         rq_srv.sr_hist_list
#define rq_history_seq          rq_srv.sr_hist_seq
#define rq_at_index             rq_srv.sr_at_index
#define rq_auth_uid             rq_srv.sr_auth_uid
#define rq_auth_mapped_uid      rq_srv.sr_auth_mapped_uid
#define rq_sp_from              rq_srv.sr_sp_from
#define rq_session              rq_srv.sr_ses
#define rq_nrq                  rq_srv.sr_nrq
#define rq_arrival_time         rq_srv.sr_arrival_time
#define rq_reply_state          rq_srv.sr_reply_state
#define rq_svc_ctx              rq_srv.sr_svc_ctx
#define rq_user_desc            rq_srv.sr_user_desc
#define rq_ops                  rq_srv.sr_ops
#define rq_rqbd                 rq_srv.sr_rqbd
#define rq_reqmsg               rq_pill.rc_reqmsg
#define rq_repmsg               rq_pill.rc_repmsg
#define rq_req_swab_mask        rq_pill.rc_req_swab_mask
#define rq_rep_swab_mask        rq_pill.rc_rep_swab_mask

/**
 * Represents remote procedure call.
 *
 * This is a staple structure used by everybody wanting to send a request
 * in Lustre.
 */
struct ptlrpc_request {
        /* Request type: one of PTL_RPC_MSG_* */
        int                              rq_type;
        /** Result of request processing */
        int                              rq_status;
        /**
         * Linkage item through which this request is included into
         * sending/delayed lists on client and into rqbd list on server
         */
        struct list_head                 rq_list;
        /** Lock to protect request flags and some other important bits, like
         * rq_list
         */
        spinlock_t                       rq_lock;
        spinlock_t                       rq_early_free_lock;
        /** client-side flags are serialized by rq_lock @{ */
        unsigned int rq_intr:1, rq_replied:1, rq_err:1,
                rq_timedout:1, rq_resend:1, rq_restart:1,
                /**
                 * when ->rq_replay is set, request is kept by the client even
                 * after server commits corresponding transaction. This is
                 * used for operations that require sequence of multiple
                 * requests to be replayed. The only example currently is file
                 * open/close. When last request in such a sequence is
                 * committed, ->rq_replay is cleared on all requests in the
                 * sequence.
                 */
                rq_replay:1,
                rq_no_resend:1, rq_waiting:1, rq_receiving_reply:1,
                rq_no_delay:1, rq_net_err:1, rq_wait_ctx:1,
                rq_early:1,
                rq_req_unlinked:1,      /* unlinked request buffer from lnet */
                rq_reply_unlinked:1,    /* unlinked reply buffer from lnet */
                rq_memalloc:1,      /* req originated from "kswapd" */
                rq_committed:1,
                rq_reply_truncated:1,
                /** whether the "rq_set" is a valid one */
                rq_invalid_rqset:1,
                rq_generation_set:1,
                /** do not resend request on -EINPROGRESS */
                rq_no_retry_einprogress:1,
                /* allow the req to be sent if the import is in recovery
                 * status */
                rq_allow_replay:1,
                /* bulk request, sent to server, but uncommitted */
                rq_unstable:1,
                rq_early_free_repbuf:1, /* free reply buffer in advance */
                rq_allow_intr:1;
        /** @} */

        /** server-side flags @{ */
        unsigned int
                rq_hp:1,                /**< high priority RPC */
                rq_at_linked:1,         /**< link into service's srv_at_array */
                rq_packed_final:1,      /**< packed final reply */
                rq_obsolete:1;          /* aborted by a signal on a client */
        /** @} */

        /** one of RQ_PHASE_* */
        enum rq_phase                    rq_phase;
        /** one of RQ_PHASE_* to be used next */
        enum rq_phase                    rq_next_phase;
        /**
         * client-side refcount for SENT race, server-side refcounf
         * for multiple replies
         */
        atomic_t                         rq_refcount;
        /**
         * client-side:
         * !rq_truncate : # reply bytes actually received,
         *  rq_truncate : required repbuf_len for resend
         */
        int rq_nob_received;
        /** Request length */
        int rq_reqlen;
        /** Reply length */
        int rq_replen;
        /** Pool if request is from preallocated list */
        struct ptlrpc_request_pool      *rq_pool;
        /** Transaction number */
        __u64 rq_transno;
        /** xid */
        __u64                            rq_xid;
        /** bulk match bits */
        __u64                            rq_mbits;
        /** reply match bits */
        __u64                            rq_rep_mbits;
        /**
         * List item to for replay list. Not yet committed requests get linked
         * there.
         * Also see \a rq_replay comment above.
         * It's also link chain on obd_export::exp_req_replay_queue
         */
        struct list_head                 rq_replay_list;
        /** non-shared members for client & server request*/
        union {
                struct ptlrpc_cli_req    rq_cli;
                struct ptlrpc_srv_req    rq_srv;
        };
        /**
         * security and encryption data
         * @{ */
        /** description of flavors for client & server */
        struct sptlrpc_flavor            rq_flvr;

        /**
         * SELinux policy info at the time of the request
         * sepol string format is:
         * <mode>:<policy name>:<policy version>:<policy hash>
         */
        char rq_sepol[LUSTRE_NODEMAP_SEPOL_LENGTH + 1];

        /* client/server security flags */
        unsigned int
                                 rq_ctx_init:1,      /* context initiation */
                                 rq_ctx_fini:1,      /* context destroy */
                                 rq_bulk_read:1,     /* request bulk read */
                                 rq_bulk_write:1,    /* request bulk write */
                                 /* server authentication flags */
                                 rq_auth_gss:1,      /* authenticated by gss */
                                 rq_auth_usr_root:1, /* authed as root */
                                 rq_auth_usr_mdt:1,  /* authed as mdt */
                                 rq_auth_usr_ost:1,  /* authed as ost */
                                 /* security tfm flags */
                                 rq_pack_udesc:1,
                                 rq_pack_bulk:1,
                                 /* doesn't expect reply FIXME */
                                 rq_no_reply:1,
                                 rq_pill_init:1, /* pill initialized */
                                 rq_srv_req:1; /* server request */


        /** various buffer pointers */
        struct lustre_msg               *rq_reqbuf;  /**< req wrapper, vmalloc*/
        char                            *rq_repbuf;  /**< rep buffer, vmalloc */
        struct lustre_msg               *rq_repdata; /**< rep wrapper msg */
        /** only in priv mode */
        struct lustre_msg               *rq_clrbuf;
        int                      rq_reqbuf_len;  /* req wrapper buf len */
        int                      rq_reqdata_len; /* req wrapper msg len */
        int                      rq_repbuf_len;  /* rep buffer len */
        int                      rq_repdata_len; /* rep wrapper msg len */
        int                      rq_clrbuf_len;  /* only in priv mode */
        int                      rq_clrdata_len; /* only in priv mode */

        /** early replies go to offset 0, regular replies go after that */
        unsigned int                     rq_reply_off;
        /** @} */

        /** how many early replies (for stats) */
        int                              rq_early_count;
        /** Server-side, export on which request was received */
        struct obd_export               *rq_export;
        /** import where request is being sent */
        struct obd_import               *rq_import;
        /** our LNet NID */
        lnet_nid_t                       rq_self;
        /** Peer description (the other side) */
        struct lnet_process_id           rq_peer;
        /** Descriptor for the NID from which the peer sent the request. */
        struct lnet_process_id           rq_source;
        /**
         * service time estimate (secs)
         * If the request is not served by this time, it is marked as timed out.
         * Do not change to time64_t since this is transmitted over the wire.
         *
         * The linux kernel handles timestamps with time64_t and timeouts
         * are normally done with jiffies. Lustre shares the rq_timeout between
         * nodes. Since jiffies can vary from node to node Lustre instead
         * will express the timeout value in seconds. To avoid confusion with
         * timestamps (time64_t) and jiffy timeouts (long) Lustre timeouts
         * are expressed in s32 (timeout_t). Also what is transmitted over
         * the wire is 32 bits.
         */
        timeout_t                        rq_timeout;
        /**
         * when request/reply sent (secs), or time when request should be sent
         */
        time64_t                         rq_sent;
        /** when request must finish. */
        time64_t                         rq_deadline;
        /** request format description */
        struct req_capsule               rq_pill;
};

/**
 * Call completion handler for rpc if any, return it's status or original
 * rc if there was no handler defined for this request.
 */
static inline int ptlrpc_req_interpret(const struct lu_env *env,
                                       struct ptlrpc_request *req, int rc)
{
        if (req->rq_interpret_reply != NULL) {
                req->rq_status = req->rq_interpret_reply(env, req,
                                                         &req->rq_async_args,
                                                         rc);
                return req->rq_status;
        }

        return rc;
}

/** \addtogroup  nrs
 * @{
 */
void ptlrpc_nrs_req_hp_move(struct ptlrpc_request *req);

/*
 * Can the request be moved from the regular NRS head to the high-priority NRS
 * head (of the same PTLRPC service partition), if any?
 *
 * For a reliable result, this should be checked under svcpt->scp_req lock.
 */
static inline bool ptlrpc_nrs_req_can_move(struct ptlrpc_request *req)
{
        struct ptlrpc_nrs_request *nrq = &req->rq_nrq;

        /**
         * LU-898: Check ptlrpc_nrs_request::nr_enqueued to make sure the
         * request has been enqueued first, and ptlrpc_nrs_request::nr_started
         * to make sure it has not been scheduled yet (analogous to previous
         * (non-NRS) checking of !list_empty(&ptlrpc_request::rq_list).
         */
        return nrq->nr_enqueued && !nrq->nr_started && !req->rq_hp;
}
/** @} nrs */

/**
 * Convert numerical request phase value \a phase into text string description
 */
static inline const char *
ptlrpc_phase2str(enum rq_phase phase)
{
        switch (phase) {
        case RQ_PHASE_NEW:
                return "New";
        case RQ_PHASE_RPC:
                return "Rpc";
        case RQ_PHASE_BULK:
                return "Bulk";
        case RQ_PHASE_INTERPRET:
                return "Interpret";
        case RQ_PHASE_COMPLETE:
                return "Complete";
        case RQ_PHASE_UNREG_RPC:
                return "UnregRPC";
        case RQ_PHASE_UNREG_BULK:
                return "UnregBULK";
        default:
                return "?Phase?";
        }
}

/**
 * Convert numerical request phase of the request \a req into text stringi
 * description
 */
static inline const char *
ptlrpc_rqphase2str(struct ptlrpc_request *req)
{
        return ptlrpc_phase2str(req->rq_phase);
}

/**
 * Debugging functions and helpers to print request structure into debug log
 * @{
 */
/* Spare the preprocessor, spoil the bugs. */
#define FLAG(field, str) (field ? str : "")

/** Convert bit flags into a string */
#define DEBUG_REQ_FLAGS(req)                                                   \
        ptlrpc_rqphase2str(req),                                               \
        FLAG(req->rq_intr, "I"), FLAG(req->rq_replied, "R"),                   \
        FLAG(req->rq_err, "E"), FLAG(req->rq_net_err, "e"),                    \
        FLAG(req->rq_timedout, "X") /* eXpired */, FLAG(req->rq_resend, "S"),  \
        FLAG(req->rq_restart, "T"), FLAG(req->rq_replay, "P"),                 \
        FLAG(req->rq_no_resend, "N"), FLAG(req->rq_no_reply, "n"),            \
        FLAG(req->rq_waiting, "W"),                                            \
        FLAG(req->rq_wait_ctx, "C"), FLAG(req->rq_hp, "H"),                    \
        FLAG(req->rq_committed, "M"),                                          \
        FLAG(req->rq_req_unlinked, "Q"),                                       \
        FLAG(req->rq_reply_unlinked, "U"),                                     \
        FLAG(req->rq_receiving_reply, "r")

#define REQ_FLAGS_FMT "%s:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s"

void _debug_req(struct ptlrpc_request *req,
                struct libcfs_debug_msg_data *data, const char *fmt, ...)
        __attribute__ ((format (printf, 3, 4)));

/**
 * Helper that decides if we need to print request accordig to current debug
 * level settings
 */
#define debug_req(msgdata, mask, cdls, req, fmt, a...)                        \
do {                                                                          \
        CFS_CHECK_STACK(msgdata, mask, cdls);                                 \
                                                                              \
        if (((mask) & D_CANTMASK) != 0 ||                                     \
            ((libcfs_debug & (mask)) != 0 &&                                  \
             (libcfs_subsystem_debug & DEBUG_SUBSYSTEM) != 0))                \
                _debug_req((req), msgdata, fmt, ##a);                         \
} while(0)

/**
 * This is the debug print function you need to use to print request sturucture
 * content into lustre debug log.
 * for most callers (level is a constant) this is resolved at compile time */
#define DEBUG_REQ(level, req, fmt, args...)                                   \
do {                                                                          \
        if ((level) & (D_ERROR | D_WARNING)) {                                \
                static struct cfs_debug_limit_state cdls;                     \
                LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, level, &cdls);            \
                debug_req(&msgdata, level, &cdls, req, "@@@ "fmt" ", ## args);\
        } else {                                                              \
                LIBCFS_DEBUG_MSG_DATA_DECL(msgdata, level, NULL);             \
                debug_req(&msgdata, level, NULL, req, "@@@ "fmt" ", ## args); \
        }                                                                     \
} while (0)
/** @} */

enum ptlrpc_bulk_op_type {
        PTLRPC_BULK_OP_ACTIVE =  0x00000001,
        PTLRPC_BULK_OP_PASSIVE = 0x00000002,
        PTLRPC_BULK_OP_PUT =     0x00000004,
        PTLRPC_BULK_OP_GET =     0x00000008,
        PTLRPC_BULK_GET_SOURCE = PTLRPC_BULK_OP_PASSIVE | PTLRPC_BULK_OP_GET,
        PTLRPC_BULK_PUT_SINK =   PTLRPC_BULK_OP_PASSIVE | PTLRPC_BULK_OP_PUT,
        PTLRPC_BULK_GET_SINK =   PTLRPC_BULK_OP_ACTIVE | PTLRPC_BULK_OP_GET,
        PTLRPC_BULK_PUT_SOURCE = PTLRPC_BULK_OP_ACTIVE | PTLRPC_BULK_OP_PUT,
};

static inline bool ptlrpc_is_bulk_op_get(enum ptlrpc_bulk_op_type type)
{
        return (type & PTLRPC_BULK_OP_GET) == PTLRPC_BULK_OP_GET;
}

static inline bool ptlrpc_is_bulk_get_source(enum ptlrpc_bulk_op_type type)
{
        return (type & PTLRPC_BULK_GET_SOURCE) == PTLRPC_BULK_GET_SOURCE;
}

static inline bool ptlrpc_is_bulk_put_sink(enum ptlrpc_bulk_op_type type)
{
        return (type & PTLRPC_BULK_PUT_SINK) == PTLRPC_BULK_PUT_SINK;
}

static inline bool ptlrpc_is_bulk_get_sink(enum ptlrpc_bulk_op_type type)
{
        return (type & PTLRPC_BULK_GET_SINK) == PTLRPC_BULK_GET_SINK;
}

static inline bool ptlrpc_is_bulk_put_source(enum ptlrpc_bulk_op_type type)
{
        return (type & PTLRPC_BULK_PUT_SOURCE) == PTLRPC_BULK_PUT_SOURCE;
}

static inline bool ptlrpc_is_bulk_op_active(enum ptlrpc_bulk_op_type type)
{
        return ((type & PTLRPC_BULK_OP_ACTIVE) |
                (type & PTLRPC_BULK_OP_PASSIVE))
                        == PTLRPC_BULK_OP_ACTIVE;
}

static inline bool ptlrpc_is_bulk_op_passive(enum ptlrpc_bulk_op_type type)
{
        return ((type & PTLRPC_BULK_OP_ACTIVE) |
                (type & PTLRPC_BULK_OP_PASSIVE))
                        == PTLRPC_BULK_OP_PASSIVE;
}

struct ptlrpc_bulk_frag_ops {
        /**
         * Add a page \a page to the bulk descriptor \a desc
         * Data to transfer in the page starts at offset \a pageoffset and
         * amount of data to transfer from the page is \a len
         */
        void (*add_kiov_frag)(struct ptlrpc_bulk_desc *desc,
                              struct page *page, int pageoffset, int len);

        /*
         * Add a \a fragment to the bulk descriptor \a desc.
         * Data to transfer in the fragment is pointed to by \a frag
         * The size of the fragment is \a len
         */
        int (*add_iov_frag)(struct ptlrpc_bulk_desc *desc, void *frag, int len);

        /**
         * Uninitialize and free bulk descriptor \a desc.
         * Works on bulk descriptors both from server and client side.
         */
        void (*release_frags)(struct ptlrpc_bulk_desc *desc);
};

extern const struct ptlrpc_bulk_frag_ops ptlrpc_bulk_kiov_pin_ops;
extern const struct ptlrpc_bulk_frag_ops ptlrpc_bulk_kiov_nopin_ops;

/*
 * Definition of bulk descriptor.
 * Bulks are special "Two phase" RPCs where initial request message
 * is sent first and it is followed bt a transfer (o receiving) of a large
 * amount of data to be settled into pages referenced from the bulk descriptors.
 * Bulks transfers (the actual data following the small requests) are done
 * on separate LNet portals.
 * In lustre we use bulk transfers for READ and WRITE transfers from/to OSTs.
 *  Another user is readpage for MDT.
 */
struct ptlrpc_bulk_desc {
        unsigned int    bd_refs; /* number MD's assigned including zero-sends */
        /** completed with failure */
        unsigned long bd_failure:1;
        /** client side */
        unsigned long bd_registered:1;
        /** For serialization with callback */
        spinlock_t bd_lock;
        /** {put,get}{source,sink}{kvec,kiov} */
        enum ptlrpc_bulk_op_type bd_type;
        /** LNet portal for this bulk */
        __u32 bd_portal;
        /** Server side - export this bulk created for */
        struct obd_export *bd_export;
        /** Client side - import this bulk was sent on */
        struct obd_import *bd_import;
        /** Back pointer to the request */
        struct ptlrpc_request *bd_req;
        const struct ptlrpc_bulk_frag_ops *bd_frag_ops;
        wait_queue_head_t      bd_waitq;        /* server side only WQ */
        int                    bd_iov_count;    /* # entries in bd_iov */
        int                    bd_max_iov;      /* allocated size of bd_iov */
        int                    bd_nob;          /* # bytes covered */
        int                    bd_nob_transferred; /* # bytes GOT/PUT */
        unsigned int            bd_nob_last;    /* # bytes in last MD */

        __u64                  bd_last_mbits;

        struct ptlrpc_cb_id    bd_cbid;         /* network callback info */
        lnet_nid_t             bd_sender;       /* stash event::sender */
        int                     bd_md_count;    /* # valid entries in bd_mds */
        int                     bd_md_max_brw;  /* max entries in bd_mds */

        /** array of offsets for each MD */
        unsigned int            bd_mds_off[PTLRPC_BULK_OPS_COUNT];
        /** array of associated MDs */
        struct lnet_handle_md   bd_mds[PTLRPC_BULK_OPS_COUNT];

        /* encrypted iov, size is either 0 or bd_iov_count. */
        struct bio_vec *bd_enc_vec;
        struct bio_vec *bd_vec;
};

enum {
        SVC_INIT        = 0,
        SVC_STOPPED     = BIT(0),
        SVC_STOPPING    = BIT(1),
        SVC_STARTING    = BIT(2),
        SVC_RUNNING     = BIT(3),
};

#define PTLRPC_THR_NAME_LEN             32
/**
 * Definition of server service thread structure
 */
struct ptlrpc_thread {
        /**
         * List of active threads in svcpt->scp_threads
         */
        struct list_head t_link;
        /**
         * thread-private data (preallocated vmalloc'd memory)
         */
        void *t_data;
        __u32 t_flags;
        /**
         * service thread index, from ptlrpc_start_threads
         */
        unsigned int t_id;
        /**
         * service thread
         */
        struct task_struct *t_task;
        pid_t t_pid;
        ktime_t t_touched;
        /**
         * put watchdog in the structure per thread b=14840
         */
        struct delayed_work t_watchdog;
        /**
         * the svc this thread belonged to b=18582
         */
        struct ptlrpc_service_part      *t_svcpt;
        wait_queue_head_t               t_ctl_waitq;
        struct lu_env                   *t_env;
        char                            t_name[PTLRPC_THR_NAME_LEN];
};

static inline int thread_is_init(struct ptlrpc_thread *thread)
{
        return thread->t_flags == 0;
}

static inline int thread_is_stopped(struct ptlrpc_thread *thread)
{
        return !!(thread->t_flags & SVC_STOPPED);
}

static inline int thread_is_stopping(struct ptlrpc_thread *thread)
{
        return !!(thread->t_flags & SVC_STOPPING);
}

static inline int thread_is_starting(struct ptlrpc_thread *thread)
{
        return !!(thread->t_flags & SVC_STARTING);
}

static inline int thread_is_running(struct ptlrpc_thread *thread)
{
        return !!(thread->t_flags & SVC_RUNNING);
}

static inline void thread_clear_flags(struct ptlrpc_thread *thread, __u32 flags)
{
        thread->t_flags &= ~flags;
}

static inline void thread_set_flags(struct ptlrpc_thread *thread, __u32 flags)
{
        thread->t_flags = flags;
}

static inline void thread_add_flags(struct ptlrpc_thread *thread, __u32 flags)
{
        thread->t_flags |= flags;
}

static inline int thread_test_and_clear_flags(struct ptlrpc_thread *thread,
                                              __u32 flags)
{
        if (thread->t_flags & flags) {
                thread->t_flags &= ~flags;
                return 1;
        }
        return 0;
}

/**
 * Request buffer descriptor structure.
 * This is a structure that contains one posted request buffer for service.
 * Once data land into a buffer, event callback creates actual request and
 * notifies wakes one of the service threads to process new incoming request.
 * More than one request can fit into the buffer.
 */
struct ptlrpc_request_buffer_desc {
        /** Link item for rqbds on a service */
        struct list_head                rqbd_list;
        /** History of requests for this buffer */
        struct list_head                rqbd_reqs;
        /** Back pointer to service for which this buffer is registered */
        struct ptlrpc_service_part      *rqbd_svcpt;
        /** LNet descriptor */
        struct lnet_handle_md           rqbd_md_h;
        int                             rqbd_refcount;
        /** The buffer itself */
        char                            *rqbd_buffer;
        struct ptlrpc_cb_id             rqbd_cbid;
        /**
         * This "embedded" request structure is only used for the
         * last request to fit into the buffer
         */
        struct ptlrpc_request           rqbd_req;
};

typedef int  (*svc_handler_t)(struct ptlrpc_request *req);

struct ptlrpc_service_ops {
        /**
         * if non-NULL called during thread creation (ptlrpc_start_thread())
         * to initialize service specific per-thread state.
         */
        int             (*so_thr_init)(struct ptlrpc_thread *thr);
        /**
         * if non-NULL called during thread shutdown (ptlrpc_main()) to
         * destruct state created by ->srv_init().
         */
        void            (*so_thr_done)(struct ptlrpc_thread *thr);
        /**
         * Handler function for incoming requests for this service
         */
        int             (*so_req_handler)(struct ptlrpc_request *req);
        /**
         * function to determine priority of the request, it's called
         * on every new request
         */
        int             (*so_hpreq_handler)(struct ptlrpc_request *);
        /**
         * service-specific print fn
         */
        void            (*so_req_printer)(void *, struct ptlrpc_request *);
};

#ifndef __cfs_cacheline_aligned
/* NB: put it here for reducing patche dependence */
# define __cfs_cacheline_aligned
#endif

/**
 * How many high priority requests to serve before serving one normal
 * priority request
 */
#define PTLRPC_SVC_HP_RATIO 10

/**
 * Definition of PortalRPC service.
 * The service is listening on a particular portal (like tcp port)
 * and perform actions for a specific server like IO service for OST
 * or general metadata service for MDS.
 */
struct ptlrpc_service {
        /** serialize /proc operations */
        spinlock_t                      srv_lock;
        /** most often accessed fields */
        /** chain thru all services */
        struct list_head                srv_list;
        /** service operations table */
        struct ptlrpc_service_ops       srv_ops;
        /** only statically allocated strings here; we don't clean them */
        char                           *srv_name;
        /** only statically allocated strings here; we don't clean them */
        char                           *srv_thread_name;
        /** threads # should be created for each partition on initializing */
        int                             srv_nthrs_cpt_init;
        /** limit of threads number for each partition */
        int                             srv_nthrs_cpt_limit;
        /** Root of debugfs dir tree for this service */
        struct dentry                  *srv_debugfs_entry;
        /** Pointer to statistic data for this service */
        struct lprocfs_stats           *srv_stats;
        /** # hp per lp reqs to handle */
        int                             srv_hpreq_ratio;
        /** biggest request to receive */
        int                             srv_max_req_size;
        /** biggest reply to send */
        int                             srv_max_reply_size;
        /** size of individual buffers */
        int                             srv_buf_size;
        /** # buffers to allocate in 1 group */
        int                             srv_nbuf_per_group;
        /** Local portal on which to receive requests */
        __u32                           srv_req_portal;
        /** Portal on the client to send replies to */
        __u32                           srv_rep_portal;
        /**
         * Tags for lu_context associated with this thread, see struct
         * lu_context.
         */
        __u32                           srv_ctx_tags;
        /** soft watchdog timeout multiplier */
        int                             srv_watchdog_factor;
        /** under unregister_service */
        unsigned                        srv_is_stopping:1;
        /** Whether or not to restrict service threads to CPUs in this CPT */
        unsigned                        srv_cpt_bind:1;

        /** max # request buffers */
        int                             srv_nrqbds_max;
        /** max # request buffers in history per partition */
        int                             srv_hist_nrqbds_cpt_max;
        /** number of CPTs this service associated with */
        int                             srv_ncpts;
        /** CPTs array this service associated with */
        __u32                           *srv_cpts;
        /** 2^srv_cptab_bits >= cfs_cpt_numbert(srv_cptable) */
        int                             srv_cpt_bits;
        /** CPT table this service is running over */
        struct cfs_cpt_table            *srv_cptable;

        /* sysfs object */
        struct kobject                  srv_kobj;
        struct completion               srv_kobj_unregister;
        /**
         * partition data for ptlrpc service
         */
        struct ptlrpc_service_part      *srv_parts[0];
};

/**
 * Definition of PortalRPC service partition data.
 * Although a service only has one instance of it right now, but we
 * will have multiple instances very soon (instance per CPT).
 *
 * it has four locks:
 * \a scp_lock
 *    serialize operations on rqbd and requests waiting for preprocess
 * \a scp_req_lock
 *    serialize operations active requests sent to this portal
 * \a scp_at_lock
 *    serialize adaptive timeout stuff
 * \a scp_rep_lock
 *    serialize operations on RS list (reply states)
 *
 * We don't have any use-case to take two or more locks at the same time
 * for now, so there is no lock order issue.
 */
struct ptlrpc_service_part {
        /** back reference to owner */
        struct ptlrpc_service           *scp_service __cfs_cacheline_aligned;
        /* CPT id, reserved */
        int                             scp_cpt;
        /** always increasing number */
        int                             scp_thr_nextid;
        /** # of starting threads */
        int                             scp_nthrs_starting;
        /** # running threads */
        int                             scp_nthrs_running;
        /** service threads list */
        struct list_head                scp_threads;

        /**
         * serialize the following fields, used for protecting
         * rqbd list and incoming requests waiting for preprocess,
         * threads starting & stopping are also protected by this lock.
         */
        spinlock_t                      scp_lock  __cfs_cacheline_aligned;
        /** userland serialization */
        struct mutex                    scp_mutex;
        /** total # req buffer descs allocated */
        int                             scp_nrqbds_total;
        /** # posted request buffers for receiving */
        int                             scp_nrqbds_posted;
        /** in progress of allocating rqbd */
        int                             scp_rqbd_allocating;
        /** # incoming reqs */
        int                             scp_nreqs_incoming;
        /** request buffers to be reposted */
        struct list_head                scp_rqbd_idle;
        /** req buffers receiving */
        struct list_head                scp_rqbd_posted;
        /** incoming reqs */
        struct list_head                scp_req_incoming;
        /** timeout before re-posting reqs, in jiffies */
        long                            scp_rqbd_timeout;
        /**
         * all threads sleep on this. This wait-queue is signalled when new
         * incoming request arrives and when difficult reply has to be handled.
         */
        wait_queue_head_t               scp_waitq;

        /** request history */
        struct list_head                scp_hist_reqs;
        /** request buffer history */
        struct list_head                scp_hist_rqbds;
        /** # request buffers in history */
        int                             scp_hist_nrqbds;
        /** sequence number for request */
        __u64                           scp_hist_seq;
        /** highest seq culled from history */
        __u64                           scp_hist_seq_culled;

        /**
         * serialize the following fields, used for processing requests
         * sent to this portal
         */
        spinlock_t                      scp_req_lock __cfs_cacheline_aligned;
        /** # reqs in either of the NRS heads below */
        /** # reqs being served */
        int                             scp_nreqs_active;
        /** # HPreqs being served */
        int                             scp_nhreqs_active;
        /** # hp requests handled */
        int                             scp_hreq_count;

        /** NRS head for regular requests */
        struct ptlrpc_nrs               scp_nrs_reg;
        /** NRS head for HP requests; this is only valid for services that can
         *  handle HP requests */
        struct ptlrpc_nrs              *scp_nrs_hp;

        /** AT stuff */
        /** @{ */
        /**
         * serialize the following fields, used for changes on
         * adaptive timeout
         */
        spinlock_t                      scp_at_lock __cfs_cacheline_aligned;
        /** estimated rpc service time */
        struct adaptive_timeout         scp_at_estimate;
        /** reqs waiting for replies */
        struct ptlrpc_at_array          scp_at_array;
        /** early reply timer */
        struct timer_list               scp_at_timer;
        /** debug */
        ktime_t                         scp_at_checktime;
        /** check early replies */
        unsigned                        scp_at_check;
        /** @} */

        /**
         * serialize the following fields, used for processing
         * replies for this portal
         */
        spinlock_t                      scp_rep_lock __cfs_cacheline_aligned;
        /** all the active replies */
        struct list_head                scp_rep_active;
        /** List of free reply_states */
        struct list_head                scp_rep_idle;
        /** waitq to run, when adding stuff to srv_free_rs_list */
        wait_queue_head_t               scp_rep_waitq;
        /** # 'difficult' replies */
        atomic_t                        scp_nreps_difficult;
};

#define ptlrpc_service_for_each_part(part, i, svc)                      \
        for (i = 0;                                                     \
             i < (svc)->srv_ncpts &&                                    \
             (svc)->srv_parts != NULL &&                                \
             ((part) = (svc)->srv_parts[i]) != NULL; i++)

/**
 * Declaration of ptlrpcd control structure
 */
struct ptlrpcd_ctl {
        /**
         * Ptlrpc thread control flags (LIOD_START, LIOD_STOP, LIOD_FORCE)
         */
        unsigned long                   pc_flags;
        /**
         * Thread lock protecting structure fields.
         */
        spinlock_t                      pc_lock;
        /**
         * Start completion.
         */
        struct completion               pc_starting;
        /**
         * Stop completion.
         */
        struct completion               pc_finishing;
        /**
         * Thread requests set.
         */
        struct ptlrpc_request_set       *pc_set;
        /**
         * Thread name used in kthread_run()
         */
        char                            pc_name[16];
        /**
         * CPT the thread is bound on.
         */
        int                             pc_cpt;
        /**
         * Index of ptlrpcd thread in the array.
         */
        int                             pc_index;
        /**
         * Pointer to the array of partners' ptlrpcd_ctl structure.
         */
        struct ptlrpcd_ctl              **pc_partners;
        /**
         * Number of the ptlrpcd's partners.
         */
        int                             pc_npartners;
        /**
         * Record the partner index to be processed next.
         */
        int                             pc_cursor;
        /**
         * Error code if the thread failed to fully start.
         */
        int                             pc_error;
};

/* Bits for pc_flags */
enum ptlrpcd_ctl_flags {
        /**
         * Ptlrpc thread start flag.
         */
        LIOD_START      = BIT(0),
        /**
         * Ptlrpc thread stop flag.
         */
        LIOD_STOP       = BIT(1),
        /**
         * Ptlrpc thread force flag (only stop force so far).
         * This will cause aborting any inflight rpcs handled
         * by thread if LIOD_STOP is specified.
         */
        LIOD_FORCE      = BIT(2),
        /**
         * This is a recovery ptlrpc thread.
         */
        LIOD_RECOVERY   = BIT(3),
};

/**
 * \addtogroup nrs
 * @{
 *
 * Service compatibility function; the policy is compatible with all services.
 *
 * \param[in] svc  The service the policy is attempting to register with.
 * \param[in] desc The policy descriptor
 *
 * \retval true The policy is compatible with the service
 *
 * \see ptlrpc_nrs_pol_desc::pd_compat()
 */
static inline bool nrs_policy_compat_all(const struct ptlrpc_service *svc,
                                         const struct ptlrpc_nrs_pol_desc *desc)
{
        return true;
}

/**
 * Service compatibility function; the policy is compatible with only a specific
 * service which is identified by its human-readable name at
 * ptlrpc_service::srv_name.
 *
 * \param[in] svc  The service the policy is attempting to register with.
 * \param[in] desc The policy descriptor
 *
 * \retval false The policy is not compatible with the service
 * \retval true  The policy is compatible with the service
 *
 * \see ptlrpc_nrs_pol_desc::pd_compat()
 */
static inline bool nrs_policy_compat_one(const struct ptlrpc_service *svc,
                                         const struct ptlrpc_nrs_pol_desc *desc)
{
        LASSERT(desc->pd_compat_svc_name != NULL);
        return strcmp(svc->srv_name, desc->pd_compat_svc_name) == 0;
}

/** @} nrs */

/* ptlrpc/events.c */
extern int ptlrpc_uuid_to_peer(struct obd_uuid *uuid,
                               struct lnet_process_id *peer, lnet_nid_t *self);
/**
 * These callbacks are invoked by LNet when something happened to
 * underlying buffer
 * @{
 */
extern void request_out_callback(struct lnet_event *ev);
extern void reply_in_callback(struct lnet_event *ev);
extern void client_bulk_callback(struct lnet_event *ev);
extern void request_in_callback(struct lnet_event *ev);
extern void reply_out_callback(struct lnet_event *ev);
#ifdef HAVE_SERVER_SUPPORT
extern void server_bulk_callback(struct lnet_event *ev);
#endif
/** @} */

/* ptlrpc/connection.c */
struct ptlrpc_connection *ptlrpc_connection_get(struct lnet_process_id peer,
                                                lnet_nid_t self,
                                                struct obd_uuid *uuid);

static inline void  ptlrpc_connection_put(struct ptlrpc_connection *conn)
{
        if (!conn)
                return;

        LASSERT(atomic_read(&conn->c_refcount) > 0);

        /*
         * We do not remove connection from hashtable and
         * do not free it even if last caller released ref,
         * as we want to have it cached for the case it is
         * needed again.
         *
         * Deallocating it and later creating new connection
         * again would be wastful. This way we also avoid
         * expensive locking to protect things from get/put
         * race when found cached connection is freed by
         * ptlrpc_connection_put().
         *
         * It will be freed later in module unload time,
         * when ptlrpc_connection_fini()->lh_exit->conn_exit()
         * path is called.
         */
        atomic_dec(&conn->c_refcount);

        CDEBUG(D_INFO, "PUT conn=%p refcount %d to %s\n",
               conn, atomic_read(&conn->c_refcount),
               libcfs_nid2str(conn->c_peer.nid));
}

struct ptlrpc_connection *ptlrpc_connection_addref(struct ptlrpc_connection *);
int ptlrpc_connection_init(void);
void ptlrpc_connection_fini(void);
extern lnet_pid_t ptl_get_pid(void);

/*
 * Check if the peer connection is on the local node.  We need to use GFP_NOFS
 * for requests from a local client to avoid recursing into the filesystem
 * as we might end up waiting on a page sent in the request we're serving.
 *
 * Use __GFP_HIGHMEM so that the pages can use all of the available memory
 * on 32-bit machines.  Use more aggressive GFP_HIGHUSER flags from non-local
 * clients to be able to generate more memory pressure on the OSS and allow
 * inactive pages to be reclaimed, since it doesn't have any other processes
 * or allocations that generate memory reclaim pressure.
 *
 * See b=17576 (bdf50dc9) and b=19529 (3dcf18d3) for details.
 */
static inline bool ptlrpc_connection_is_local(struct ptlrpc_connection *conn)
{
        if (!conn)
                return false;

        if (conn->c_peer.nid == conn->c_self)
                return true;

        RETURN(LNetIsPeerLocal(conn->c_peer.nid));
}

/* ptlrpc/niobuf.c */
/**
 * Actual interfacing with LNet to put/get/register/unregister stuff
 * @{
 */
#ifdef HAVE_SERVER_SUPPORT
struct ptlrpc_bulk_desc *ptlrpc_prep_bulk_exp(struct ptlrpc_request *req,
                                              unsigned nfrags, unsigned max_brw,
                                              unsigned int type,
                                              unsigned portal,
                                              const struct ptlrpc_bulk_frag_ops
                                                *ops);
int ptlrpc_start_bulk_transfer(struct ptlrpc_bulk_desc *desc);
void ptlrpc_abort_bulk(struct ptlrpc_bulk_desc *desc);

static inline int ptlrpc_server_bulk_active(struct ptlrpc_bulk_desc *desc)
{
        int rc;

        LASSERT(desc != NULL);

        spin_lock(&desc->bd_lock);
        rc = desc->bd_refs;
        spin_unlock(&desc->bd_lock);
        return rc;
}
#endif

int ptlrpc_register_bulk(struct ptlrpc_request *req);
int ptlrpc_unregister_bulk(struct ptlrpc_request *req, int async);

static inline int ptlrpc_client_bulk_active(struct ptlrpc_request *req)
{
        struct ptlrpc_bulk_desc *desc;
        int rc;

        LASSERT(req != NULL);
        desc = req->rq_bulk;

        if (!desc)
                return 0;

        if (req->rq_bulk_deadline > ktime_get_real_seconds())
                return 1;


        spin_lock(&desc->bd_lock);
        rc = desc->bd_refs;
        spin_unlock(&desc->bd_lock);
        return rc;
}

#define PTLRPC_REPLY_MAYBE_DIFFICULT 0x01
#define PTLRPC_REPLY_EARLY           0x02
int ptlrpc_send_reply(struct ptlrpc_request *req, int flags);
int ptlrpc_reply(struct ptlrpc_request *req);
int ptlrpc_send_error(struct ptlrpc_request *req, int difficult);
int ptlrpc_error(struct ptlrpc_request *req);
int ptlrpc_at_get_net_latency(struct ptlrpc_request *req);
int ptl_send_rpc(struct ptlrpc_request *request, int noreply);
int ptlrpc_register_rqbd(struct ptlrpc_request_buffer_desc *rqbd);
/** @} */

/* ptlrpc/client.c */
/**
 * Client-side portals API. Everything to send requests, receive replies,
 * request queues, request management, etc.
 * @{
 */
void ptlrpc_request_committed(struct ptlrpc_request *req, int force);

void ptlrpc_init_client(int req_portal, int rep_portal, const char *name,
                        struct ptlrpc_client *);
void ptlrpc_cleanup_client(struct obd_import *imp);
struct ptlrpc_connection *ptlrpc_uuid_to_connection(struct obd_uuid *uuid,
                                                    lnet_nid_t nid4refnet);

int ptlrpc_queue_wait(struct ptlrpc_request *req);
int ptlrpc_replay_req(struct ptlrpc_request *req);
void ptlrpc_restart_req(struct ptlrpc_request *req);
void ptlrpc_abort_inflight(struct obd_import *imp);
void ptlrpc_cleanup_imp(struct obd_import *imp);
void ptlrpc_abort_set(struct ptlrpc_request_set *set);

struct ptlrpc_request_set *ptlrpc_prep_set(void);
struct ptlrpc_request_set *ptlrpc_prep_fcset(int max, set_producer_func func,
                                             void *arg);
int ptlrpc_check_set(const struct lu_env *env, struct ptlrpc_request_set *set);
int ptlrpc_set_wait(const struct lu_env *env, struct ptlrpc_request_set *);
void ptlrpc_set_destroy(struct ptlrpc_request_set *);
void ptlrpc_set_add_req(struct ptlrpc_request_set *, struct ptlrpc_request *);
#define PTLRPCD_SET ((struct ptlrpc_request_set *)1)

void ptlrpc_free_rq_pool(struct ptlrpc_request_pool *pool);
int ptlrpc_add_rqs_to_pool(struct ptlrpc_request_pool *pool, int num_rq);

struct ptlrpc_request_pool *
ptlrpc_init_rq_pool(int, int,
                    int (*populate_pool)(struct ptlrpc_request_pool *, int));

void ptlrpc_at_set_req_timeout(struct ptlrpc_request *req);
struct ptlrpc_request *ptlrpc_request_alloc(struct obd_import *imp,
                                            const struct req_format *format);
struct ptlrpc_request *ptlrpc_request_alloc_pool(struct obd_import *imp,
                                            struct ptlrpc_request_pool *,
                                            const struct req_format *format);
void ptlrpc_request_free(struct ptlrpc_request *request);
int ptlrpc_request_pack(struct ptlrpc_request *request,
                        __u32 version, int opcode);
struct ptlrpc_request *ptlrpc_request_alloc_pack(struct obd_import *imp,
                                                const struct req_format *format,
                                                __u32 version, int opcode);
int ptlrpc_request_bufs_pack(struct ptlrpc_request *request,
                             __u32 version, int opcode, char **bufs,
                             struct ptlrpc_cli_ctx *ctx);
void ptlrpc_req_finished(struct ptlrpc_request *request);
void ptlrpc_req_finished_with_imp_lock(struct ptlrpc_request *request);
struct ptlrpc_request *ptlrpc_request_addref(struct ptlrpc_request *req);
struct ptlrpc_bulk_desc *ptlrpc_prep_bulk_imp(struct ptlrpc_request *req,
                                              unsigned nfrags, unsigned max_brw,
                                              unsigned int type,
                                              unsigned portal,
                                              const struct ptlrpc_bulk_frag_ops
                                                *ops);

void __ptlrpc_prep_bulk_page(struct ptlrpc_bulk_desc *desc,
                             struct page *page, int pageoffset, int len,
                             int pin);

void ptlrpc_free_bulk(struct ptlrpc_bulk_desc *bulk);

static inline void ptlrpc_release_bulk_noop(struct ptlrpc_bulk_desc *desc)
{
}

void ptlrpc_retain_replayable_request(struct ptlrpc_request *req,
                                      struct obd_import *imp);
__u64 ptlrpc_next_xid(void);
__u64 ptlrpc_sample_next_xid(void);
__u64 ptlrpc_req_xid(struct ptlrpc_request *request);
void ptlrpc_get_mod_rpc_slot(struct ptlrpc_request *req);
void ptlrpc_put_mod_rpc_slot(struct ptlrpc_request *req);

/* Set of routines to run a function in ptlrpcd context */
void *ptlrpcd_alloc_work(struct obd_import *imp,
                         int (*cb)(const struct lu_env *, void *), void *data);
void ptlrpcd_destroy_work(void *handler);
int ptlrpcd_queue_work(void *handler);

/** @} */
struct ptlrpc_service_buf_conf {
        /* nbufs is buffers # to allocate when growing the pool */
        unsigned int                    bc_nbufs;
        /* buffer size to post */
        unsigned int                    bc_buf_size;
        /* portal to listed for requests on */
        unsigned int                    bc_req_portal;
        /* portal of where to send replies to */
        unsigned int                    bc_rep_portal;
        /* maximum request size to be accepted for this service */
        unsigned int                    bc_req_max_size;
        /* maximum reply size this service can ever send */
        unsigned int                    bc_rep_max_size;
};

struct ptlrpc_service_thr_conf {
        /* threadname should be 8 characters or less - 6 will be added on */
        char                            *tc_thr_name;
        /* threads increasing factor for each CPU */
        unsigned int                    tc_thr_factor;
        /* service threads # to start on each partition while initializing */
        unsigned int                    tc_nthrs_init;
        /*
         * low water of threads # upper-limit on each partition while running,
         * service availability may be impacted if threads number is lower
         * than this value. It can be ZERO if the service doesn't require
         * CPU affinity or there is only one partition.
         */
        unsigned int                    tc_nthrs_base;
        /* "soft" limit for total threads number */
        unsigned int                    tc_nthrs_max;
        /* user specified threads number, it will be validated due to
         * other members of this structure. */
        unsigned int                    tc_nthrs_user;
        /* bind service threads to only CPUs in their associated CPT */
        unsigned int                    tc_cpu_bind;
        /* Tags for lu_context associated with service thread */
        __u32                           tc_ctx_tags;
};

struct ptlrpc_service_cpt_conf {
        struct cfs_cpt_table            *cc_cptable;
        /* string pattern to describe CPTs for a service */
        char                            *cc_pattern;
        /* whether or not to have per-CPT service partitions */
        bool                            cc_affinity;
};

struct ptlrpc_service_conf {
        /* service name */
        char                            *psc_name;
        /* soft watchdog timeout multiplifier to print stuck service traces */
        unsigned int                    psc_watchdog_factor;
        /* buffer information */
        struct ptlrpc_service_buf_conf  psc_buf;
        /* thread information */
        struct ptlrpc_service_thr_conf  psc_thr;
        /* CPU partition information */
        struct ptlrpc_service_cpt_conf  psc_cpt;
        /* function table */
        struct ptlrpc_service_ops       psc_ops;
};

/* ptlrpc/service.c */
/**
 * Server-side services API. Register/unregister service, request state
 * management, service thread management
 *
 * @{
 */
void ptlrpc_save_lock(struct ptlrpc_request *req, struct lustre_handle *lock,
                      int mode, bool no_ack, bool convert_lock);
void ptlrpc_commit_replies(struct obd_export *exp);
void ptlrpc_dispatch_difficult_reply(struct ptlrpc_reply_state *rs);
void ptlrpc_schedule_difficult_reply(struct ptlrpc_reply_state *rs);
int ptlrpc_hpreq_handler(struct ptlrpc_request *req);
struct ptlrpc_service *ptlrpc_register_service(
                                struct ptlrpc_service_conf *conf,
                                struct kset *parent,
                                struct dentry *debugfs_entry);

int ptlrpc_unregister_service(struct ptlrpc_service *service);
int ptlrpc_service_health_check(struct ptlrpc_service *);
void ptlrpc_server_drop_request(struct ptlrpc_request *req);
void ptlrpc_request_change_export(struct ptlrpc_request *req,
                                  struct obd_export *export);
void ptlrpc_update_export_timer(struct obd_export *exp,
                                time64_t extra_delay);

int ptlrpc_hr_init(void);
void ptlrpc_hr_fini(void);

void ptlrpc_watchdog_init(struct delayed_work *work, timeout_t timeout);
void ptlrpc_watchdog_disable(struct delayed_work *work);
void ptlrpc_watchdog_touch(struct delayed_work *work, timeout_t timeout);

/** @} */

/* ptlrpc/import.c */
/**
 * Import API
 * @{
 */
int ptlrpc_connect_import(struct obd_import *imp);
int ptlrpc_connect_import_locked(struct obd_import *imp);
int ptlrpc_init_import(struct obd_import *imp);
int ptlrpc_disconnect_import(struct obd_import *imp, int noclose);
int ptlrpc_disconnect_and_idle_import(struct obd_import *imp);
int ptlrpc_import_recovery_state_machine(struct obd_import *imp);
void deuuidify(char *uuid, const char *prefix, char **uuid_start,
               int *uuid_len);
void ptlrpc_import_enter_resend(struct obd_import *imp);
/* ptlrpc/pack_generic.c */
int ptlrpc_reconnect_import(struct obd_import *imp);
/** @} */

/**
 * ptlrpc msg buffer and swab interface
 *
 * @{
 */
#define PTLRPC_MAX_BUFCOUNT \
        (sizeof(((struct ptlrpc_request *)0)->rq_req_swab_mask) * 8)
#define MD_MAX_BUFLEN           (MDS_REG_MAXREQSIZE > OUT_MAXREQSIZE ? \
                                 MDS_REG_MAXREQSIZE : OUT_MAXREQSIZE)
#define PTLRPC_MAX_BUFLEN       (OST_IO_MAXREQSIZE > MD_MAX_BUFLEN ? \
                                 OST_IO_MAXREQSIZE : MD_MAX_BUFLEN)
int ptlrpc_unpack_rep_msg(struct ptlrpc_request *req, int len);
int ptlrpc_unpack_req_msg(struct ptlrpc_request *req, int len);

int lustre_msg_check_version(struct lustre_msg *msg, __u32 version);
void lustre_init_msg_v2(struct lustre_msg_v2 *msg, int count, __u32 *lens,
                        char **bufs);
int lustre_pack_request(struct ptlrpc_request *, __u32 magic, int count,
                        __u32 *lens, char **bufs);
int lustre_pack_reply(struct ptlrpc_request *, int count, __u32 *lens,
                      char **bufs);
int lustre_pack_reply_v2(struct ptlrpc_request *req, int count,
                         __u32 *lens, char **bufs, int flags);
#define LPRFL_EARLY_REPLY 1
int lustre_pack_reply_flags(struct ptlrpc_request *, int count, __u32 *lens,
                            char **bufs, int flags);
int lustre_shrink_msg(struct lustre_msg *msg, int segment,
                      unsigned int newlen, int move_data);
int lustre_grow_msg(struct lustre_msg *msg, int segment, unsigned int newlen);
void lustre_free_reply_state(struct ptlrpc_reply_state *rs);
int __lustre_unpack_msg(struct lustre_msg *m, int len);
__u32 lustre_msg_hdr_size(__u32 magic, __u32 count);
__u32 lustre_msg_size(__u32 magic, int count, __u32 *lengths);
__u32 lustre_msg_size_v2(int count, __u32 *lengths);
__u32 lustre_packed_msg_size(struct lustre_msg *msg);
__u32 lustre_msg_early_size(void);
void *lustre_msg_buf_v2(struct lustre_msg_v2 *m, __u32 n, __u32 min_size);
void *lustre_msg_buf(struct lustre_msg *m, __u32 n, __u32 minlen);
__u32 lustre_msg_buflen(struct lustre_msg *m, __u32 n);
void lustre_msg_set_buflen(struct lustre_msg *m, __u32 n, __u32 len);
__u32 lustre_msg_bufcount(struct lustre_msg *m);
char *lustre_msg_string(struct lustre_msg *m, __u32 n, __u32 max_len);
__u32 lustre_msghdr_get_flags(struct lustre_msg *msg);
void lustre_msghdr_set_flags(struct lustre_msg *msg, __u32 flags);
__u32 lustre_msg_get_flags(struct lustre_msg *msg);
void lustre_msg_add_flags(struct lustre_msg *msg, __u32 flags);
void lustre_msg_set_flags(struct lustre_msg *msg, __u32 flags);
void lustre_msg_clear_flags(struct lustre_msg *msg, __u32 flags);
__u32 lustre_msg_get_op_flags(struct lustre_msg *msg);
void lustre_msg_add_op_flags(struct lustre_msg *msg, __u32 flags);
struct lustre_handle *lustre_msg_get_handle(struct lustre_msg *msg);
__u32 lustre_msg_get_type(struct lustre_msg *msg);
enum lustre_msg_version lustre_msg_get_version(struct lustre_msg *msg);
void lustre_msg_add_version(struct lustre_msg *msg, __u32 version);
__u32 lustre_msg_get_opc(struct lustre_msg *msg);
__u64 lustre_msg_get_last_xid(struct lustre_msg *msg);
__u16 lustre_msg_get_tag(struct lustre_msg *msg);
__u64 lustre_msg_get_last_committed(struct lustre_msg *msg);
__u64 *lustre_msg_get_versions(struct lustre_msg *msg);
__u64 lustre_msg_get_transno(struct lustre_msg *msg);
__u64 lustre_msg_get_slv(struct lustre_msg *msg);
__u32 lustre_msg_get_limit(struct lustre_msg *msg);
void lustre_msg_set_slv(struct lustre_msg *msg, __u64 slv);
void lustre_msg_set_limit(struct lustre_msg *msg, __u64 limit);
int lustre_msg_get_status(struct lustre_msg *msg);
__u32 lustre_msg_get_conn_cnt(struct lustre_msg *msg);
__u32 lustre_msg_get_magic(struct lustre_msg *msg);
timeout_t lustre_msg_get_timeout(struct lustre_msg *msg);
timeout_t lustre_msg_get_service_timeout(struct lustre_msg *msg);
char *lustre_msg_get_jobid(struct lustre_msg *msg);
__u32 lustre_msg_get_cksum(struct lustre_msg *msg);
__u64 lustre_msg_get_mbits(struct lustre_msg *msg);
__u32 lustre_msg_calc_cksum(struct lustre_msg *msg, __u32 buf);
void lustre_msg_set_handle(struct lustre_msg *msg,struct lustre_handle *handle);
void lustre_msg_set_type(struct lustre_msg *msg, __u32 type);
void lustre_msg_set_opc(struct lustre_msg *msg, __u32 opc);
void lustre_msg_set_last_xid(struct lustre_msg *msg, __u64 last_xid);
void lustre_msg_set_tag(struct lustre_msg *msg, __u16 tag);
void lustre_msg_set_last_committed(struct lustre_msg *msg,__u64 last_committed);
void lustre_msg_set_versions(struct lustre_msg *msg, __u64 *versions);
void lustre_msg_set_transno(struct lustre_msg *msg, __u64 transno);
void lustre_msg_set_status(struct lustre_msg *msg, __u32 status);
void lustre_msg_set_conn_cnt(struct lustre_msg *msg, __u32 conn_cnt);
void ptlrpc_req_set_repsize(struct ptlrpc_request *req, int count, __u32 *sizes);
void ptlrpc_request_set_replen(struct ptlrpc_request *req);
void lustre_msg_set_timeout(struct lustre_msg *msg, timeout_t timeout);
void lustre_msg_set_service_timeout(struct lustre_msg *msg,
                                    timeout_t service_timeout);
void lustre_msg_set_jobid(struct lustre_msg *msg, char *jobid);
void lustre_msg_set_cksum(struct lustre_msg *msg, __u32 cksum);
void lustre_msg_set_mbits(struct lustre_msg *msg, __u64 mbits);

static inline void
lustre_shrink_reply(struct ptlrpc_request *req, int segment,
                    unsigned int newlen, int move_data)
{
        LASSERT(req->rq_reply_state);
        LASSERT(req->rq_repmsg);
        req->rq_replen = lustre_shrink_msg(req->rq_repmsg, segment,
                                           newlen, move_data);
}

#ifdef LUSTRE_TRANSLATE_ERRNOS

static inline int ptlrpc_status_hton(int h)
{
        /*
         * Positive errnos must be network errnos, such as LUSTRE_EDEADLK,
         * ELDLM_LOCK_ABORTED, etc.
         */
        if (h < 0)
                return -lustre_errno_hton(-h);
        else
                return h;
}

static inline int ptlrpc_status_ntoh(int n)
{
        /*
         * See the comment in ptlrpc_status_hton().
         */
        if (n < 0)
                return -lustre_errno_ntoh(-n);
        else
                return n;
}

#else

#define ptlrpc_status_hton(h) (h)
#define ptlrpc_status_ntoh(n) (n)

#endif
/** @} */

/** Change request phase of \a req to \a new_phase */
static inline void
ptlrpc_rqphase_move(struct ptlrpc_request *req, enum rq_phase new_phase)
{
        if (req->rq_phase == new_phase)
                return;

        if (new_phase == RQ_PHASE_UNREG_RPC ||
            new_phase == RQ_PHASE_UNREG_BULK) {
                /* No embedded unregistering phases */
                if (req->rq_phase == RQ_PHASE_UNREG_RPC ||
                    req->rq_phase == RQ_PHASE_UNREG_BULK)
                        return;

                req->rq_next_phase = req->rq_phase;
                if (req->rq_import)
                        atomic_inc(&req->rq_import->imp_unregistering);
        }

        if (req->rq_phase == RQ_PHASE_UNREG_RPC ||
            req->rq_phase == RQ_PHASE_UNREG_BULK) {
                if (req->rq_import)
                        atomic_dec(&req->rq_import->imp_unregistering);
        }

        DEBUG_REQ(D_INFO, req, "move request phase from %s to %s",
                  ptlrpc_rqphase2str(req), ptlrpc_phase2str(new_phase));

        req->rq_phase = new_phase;
}

/**
 * Returns true if request \a req got early reply and hard deadline is not met
 */
static inline int
ptlrpc_client_early(struct ptlrpc_request *req)
{
        return req->rq_early;
}

/**
 * Returns true if we got real reply from server for this request
 */
static inline int
ptlrpc_client_replied(struct ptlrpc_request *req)
{
        if (req->rq_reply_deadline > ktime_get_real_seconds())
                return 0;
        return req->rq_replied;
}

/** Returns true if request \a req is in process of receiving server reply */
static inline int
ptlrpc_client_recv(struct ptlrpc_request *req)
{
        if (req->rq_reply_deadline > ktime_get_real_seconds())
                return 1;
        return req->rq_receiving_reply;
}

#define ptlrpc_cli_wait_unlink(req) __ptlrpc_cli_wait_unlink(req, NULL)

static inline int
__ptlrpc_cli_wait_unlink(struct ptlrpc_request *req, bool *discard)
{
        int rc;

        spin_lock(&req->rq_lock);
        if (req->rq_reply_deadline > ktime_get_real_seconds()) {
                spin_unlock(&req->rq_lock);
                return 1;
        }
        if (req->rq_req_deadline > ktime_get_real_seconds()) {
                spin_unlock(&req->rq_lock);
                return 1;
        }

        if (discard) {
                *discard = false;
                if (req->rq_reply_unlinked && req->rq_req_unlinked == 0) {
                        *discard = true;
                        spin_unlock(&req->rq_lock);
                        return 1; /* Should call again after LNetMDUnlink */
                }
        }

        rc = !req->rq_req_unlinked || !req->rq_reply_unlinked ||
             req->rq_receiving_reply;
        spin_unlock(&req->rq_lock);
        return rc;
}

static inline void
ptlrpc_client_wake_req(struct ptlrpc_request *req)
{
        smp_mb();
        if (req->rq_set == NULL)
                wake_up(&req->rq_reply_waitq);
        else
                wake_up(&req->rq_set->set_waitq);
}

static inline void
ptlrpc_rs_addref(struct ptlrpc_reply_state *rs)
{
        LASSERT(atomic_read(&rs->rs_refcount) > 0);
        atomic_inc(&rs->rs_refcount);
}

static inline void
ptlrpc_rs_decref(struct ptlrpc_reply_state *rs)
{
        LASSERT(atomic_read(&rs->rs_refcount) > 0);
        if (atomic_dec_and_test(&rs->rs_refcount))
                lustre_free_reply_state(rs);
}

/* Should only be called once per req */
static inline void ptlrpc_req_drop_rs(struct ptlrpc_request *req)
{
        if (req->rq_reply_state == NULL)
                return; /* shouldn't occur */
        ptlrpc_rs_decref(req->rq_reply_state);
        req->rq_reply_state = NULL;
        req->rq_repmsg = NULL;
}

static inline __u32 lustre_request_magic(struct ptlrpc_request *req)
{
        return lustre_msg_get_magic(req->rq_reqmsg);
}

static inline int ptlrpc_req_get_repsize(struct ptlrpc_request *req)
{
        switch (req->rq_reqmsg->lm_magic) {
        case LUSTRE_MSG_MAGIC_V2:
                return req->rq_reqmsg->lm_repsize;
        default:
                LASSERTF(0, "incorrect message magic: %08x\n",
                         req->rq_reqmsg->lm_magic);
                return -EFAULT;
        }
}

static inline int ptlrpc_send_limit_expired(struct ptlrpc_request *req)
{
        if (req->rq_delay_limit != 0 &&
            req->rq_queued_time + req->rq_delay_limit < ktime_get_seconds())
                return 1;
        return 0;
}

static inline int ptlrpc_no_resend(struct ptlrpc_request *req)
{
        if (!req->rq_no_resend && ptlrpc_send_limit_expired(req)) {
                spin_lock(&req->rq_lock);
                req->rq_no_resend = 1;
                spin_unlock(&req->rq_lock);
        }
        return req->rq_no_resend;
}

static inline int
ptlrpc_server_get_timeout(struct ptlrpc_service_part *svcpt)
{
        int at = AT_OFF ? 0 : at_get(&svcpt->scp_at_estimate);

        return svcpt->scp_service->srv_watchdog_factor *
               max_t(int, at, obd_timeout);
}

/**
 * Calculate the amount of time for lock prolongation.
 *
 * This is helper function to get the timeout extra time.
 *
 * @req         current request
 *
 * Return:      amount of time to extend the timeout with
 */
static inline timeout_t prolong_timeout(struct ptlrpc_request *req)
{
        struct ptlrpc_service_part *svcpt = req->rq_rqbd->rqbd_svcpt;
        timeout_t req_timeout = 0;

        if (AT_OFF)
                return obd_timeout / 2;

        if (req->rq_deadline > req->rq_arrival_time.tv_sec)
                req_timeout = req->rq_deadline - req->rq_arrival_time.tv_sec;

        return max(req_timeout,
                   at_est2timeout(at_get(&svcpt->scp_at_estimate)));
}

static inline struct ptlrpc_service *
ptlrpc_req2svc(struct ptlrpc_request *req)
{
        LASSERT(req->rq_rqbd != NULL);
        return req->rq_rqbd->rqbd_svcpt->scp_service;
}

/* ldlm/ldlm_lib.c */
/**
 * Target client logic
 * @{
 */
int client_obd_setup(struct obd_device *obd, struct lustre_cfg *lcfg);
int client_obd_cleanup(struct obd_device *obd);
int client_connect_import(const struct lu_env *env,
                          struct obd_export **exp, struct obd_device *obd,
                          struct obd_uuid *cluuid, struct obd_connect_data *,
                          void *localdata);
int client_disconnect_export(struct obd_export *exp);
int client_import_add_conn(struct obd_import *imp, struct obd_uuid *uuid,
                           int priority);
int client_import_dyn_add_conn(struct obd_import *imp, struct obd_uuid *uuid,
                               lnet_nid_t prim_nid, int priority);
int client_import_add_nids_to_conn(struct obd_import *imp, lnet_nid_t *nids,
                                   int nid_count, struct obd_uuid *uuid);
int client_import_del_conn(struct obd_import *imp, struct obd_uuid *uuid);
int client_import_find_conn(struct obd_import *imp, lnet_nid_t peer,
                            struct obd_uuid *uuid);
int import_set_conn_priority(struct obd_import *imp, struct obd_uuid *uuid);
void client_destroy_import(struct obd_import *imp);
/** @} */

#ifdef HAVE_SERVER_SUPPORT
int server_disconnect_export(struct obd_export *exp);
#endif

/* ptlrpc/pinger.c */
/**
 * Pinger API (client side only)
 * @{
 */
enum timeout_event {
        TIMEOUT_GRANT = 1
};
struct timeout_item;
typedef int (*timeout_cb_t)(struct timeout_item *, void *);
int ptlrpc_pinger_add_import(struct obd_import *imp);
int ptlrpc_pinger_del_import(struct obd_import *imp);
struct ptlrpc_request * ptlrpc_prep_ping(struct obd_import *imp);
int ptlrpc_obd_ping(struct obd_device *obd);
void ping_evictor_start(void);
void ping_evictor_stop(void);
void ptlrpc_pinger_ir_up(void);
void ptlrpc_pinger_ir_down(void);
/** @} */
int ptlrpc_pinger_suppress_pings(void);

/* ptlrpc/ptlrpcd.c */
void ptlrpcd_stop(struct ptlrpcd_ctl *pc, int force);
void ptlrpcd_free(struct ptlrpcd_ctl *pc);
void ptlrpcd_wake(struct ptlrpc_request *req);
void ptlrpcd_add_req(struct ptlrpc_request *req);
void ptlrpcd_add_rqset(struct ptlrpc_request_set *set);
int ptlrpcd_addref(void);
void ptlrpcd_decref(void);

/* ptlrpc/lproc_ptlrpc.c */
/**
 * procfs output related functions
 * @{
 */
const char* ll_opcode2str(__u32 opcode);
const int ll_str2opcode(const char *ops);
#ifdef CONFIG_PROC_FS
void ptlrpc_lprocfs_register_obd(struct obd_device *obd);
void ptlrpc_lprocfs_unregister_obd(struct obd_device *obd);
void ptlrpc_lprocfs_brw(struct ptlrpc_request *req, int bytes);
#else
static inline void ptlrpc_lprocfs_register_obd(struct obd_device *obd) {}
static inline void ptlrpc_lprocfs_unregister_obd(struct obd_device *obd) {}
static inline void ptlrpc_lprocfs_brw(struct ptlrpc_request *req, int bytes) {}
#endif
/** @} */

/* ptlrpc/llog_server.c */
int llog_origin_handle_open(struct ptlrpc_request *req);
int llog_origin_handle_prev_block(struct ptlrpc_request *req);
int llog_origin_handle_next_block(struct ptlrpc_request *req);
int llog_origin_handle_read_header(struct ptlrpc_request *req);

/* ptlrpc/llog_client.c */
extern const struct llog_operations llog_client_ops;
/** @} net */

#endif
/** @} PtlRPC */