/*
 * 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.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lnet/lnet/lib-md.c
 *
 * Memory Descriptor management routines
 */

#define DEBUG_SUBSYSTEM S_LNET

#include <lnet/lib-lnet.h>

/* must be called with lnet_res_lock held */
void
lnet_md_unlink(lnet_libmd_t *md)
{
        if ((md->md_flags & LNET_MD_FLAG_ZOMBIE) == 0) {
                /* first unlink attempt... */
                lnet_me_t *me = md->md_me;

                md->md_flags |= LNET_MD_FLAG_ZOMBIE;

                /* Disassociate from ME (if any), and unlink it if it was created
                 * with LNET_UNLINK */
                if (me != NULL) {
			/* detach MD from portal */
			lnet_ptl_detach_md(me, md);
                        if (me->me_unlink == LNET_UNLINK)
                                lnet_me_unlink(me);
                }

                /* ensure all future handle lookups fail */
		lnet_res_lh_invalidate(&md->md_lh);
        }

        if (md->md_refcount != 0) {
                CDEBUG(D_NET, "Queueing unlink of md %p\n", md);
                return;
        }

        CDEBUG(D_NET, "Unlinking md %p\n", md);

        if (md->md_eq != NULL) {
                md->md_eq->eq_refcount--;
                LASSERT (md->md_eq->eq_refcount >= 0);
        }

        LASSERT (!cfs_list_empty(&md->md_list));
        cfs_list_del_init (&md->md_list);
	lnet_md_free_locked(md);
}

static int
lnet_md_build(lnet_libmd_t *lmd, lnet_md_t *umd, int unlink)
{
        int          i;
        unsigned int niov;
        int          total_length = 0;

        lmd->md_me = NULL;
        lmd->md_start = umd->start;
        lmd->md_offset = 0;
        lmd->md_max_size = umd->max_size;
        lmd->md_options = umd->options;
        lmd->md_user_ptr = umd->user_ptr;
	lmd->md_eq = NULL;
        lmd->md_threshold = umd->threshold;
        lmd->md_refcount = 0;
        lmd->md_flags = (unlink == LNET_UNLINK) ? LNET_MD_FLAG_AUTO_UNLINK : 0;

        if ((umd->options & LNET_MD_IOVEC) != 0) {

                if ((umd->options & LNET_MD_KIOV) != 0) /* Can't specify both */
                        return -EINVAL;

                lmd->md_niov = niov = umd->length;
                memcpy(lmd->md_iov.iov, umd->start,
                       niov * sizeof (lmd->md_iov.iov[0]));

                for (i = 0; i < (int)niov; i++) {
                        /* We take the base address on trust */
                        if (lmd->md_iov.iov[i].iov_len <= 0) /* invalid length */
                                return -EINVAL;

                        total_length += lmd->md_iov.iov[i].iov_len;
                }

                lmd->md_length = total_length;

                if ((umd->options & LNET_MD_MAX_SIZE) != 0 && /* max size used */
                    (umd->max_size < 0 ||
                     umd->max_size > total_length)) // illegal max_size
                        return -EINVAL;

        } else if ((umd->options & LNET_MD_KIOV) != 0) {
#ifndef __KERNEL__
                return -EINVAL;
#else
                lmd->md_niov = niov = umd->length;
                memcpy(lmd->md_iov.kiov, umd->start,
                       niov * sizeof (lmd->md_iov.kiov[0]));

                for (i = 0; i < (int)niov; i++) {
                        /* We take the page pointer on trust */
                        if (lmd->md_iov.kiov[i].kiov_offset +
                            lmd->md_iov.kiov[i].kiov_len > CFS_PAGE_SIZE )
                                return -EINVAL; /* invalid length */

                        total_length += lmd->md_iov.kiov[i].kiov_len;
                }

                lmd->md_length = total_length;

                if ((umd->options & LNET_MD_MAX_SIZE) != 0 && /* max size used */
                    (umd->max_size < 0 ||
                     umd->max_size > total_length)) // illegal max_size
                        return -EINVAL;
#endif
        } else {   /* contiguous */
                lmd->md_length = umd->length;
                lmd->md_niov = niov = 1;
                lmd->md_iov.iov[0].iov_base = umd->start;
                lmd->md_iov.iov[0].iov_len = umd->length;

                if ((umd->options & LNET_MD_MAX_SIZE) != 0 && /* max size used */
                    (umd->max_size < 0 ||
                     umd->max_size > (int)umd->length)) // illegal max_size
                        return -EINVAL;
        }

	return 0;
}

/* must be called with resource lock held */
static int
lnet_md_link(lnet_libmd_t *md, lnet_handle_eq_t eq_handle)
{
	struct lnet_res_container *container = &the_lnet.ln_md_container;

	/* NB we are passed an allocated, but inactive md.
	 * if we return success, caller may lnet_md_unlink() it.
	 * otherwise caller may only lnet_md_free() it.
	 */
	/* This implementation doesn't know how to create START events or
	 * disable END events.  Best to LASSERT our caller is compliant so
	 * we find out quickly...  */
	/*  TODO - reevaluate what should be here in light of
	 * the removal of the start and end events
	 * maybe there we shouldn't even allow LNET_EQ_NONE!)
	 * LASSERT (eq == NULL);
	 */
	if (!LNetHandleIsInvalid(eq_handle)) {
		md->md_eq = lnet_handle2eq(&eq_handle);

		if (md->md_eq == NULL)
			return -ENOENT;

		md->md_eq->eq_refcount++;
	}

	lnet_res_lh_initialize(container, &md->md_lh);

	LASSERT(cfs_list_empty(&md->md_list));
	cfs_list_add(&md->md_list, &container->rec_active);

	return 0;
}

/* must be called with lnet_res_lock held */
void
lnet_md_deconstruct(lnet_libmd_t *lmd, lnet_md_t *umd)
{
        /* NB this doesn't copy out all the iov entries so when a
         * discontiguous MD is copied out, the target gets to know the
         * original iov pointer (in start) and the number of entries it had
         * and that's all.
         */
        umd->start = lmd->md_start;
        umd->length = ((lmd->md_options & (LNET_MD_IOVEC | LNET_MD_KIOV)) == 0) ?
                      lmd->md_length : lmd->md_niov;
        umd->threshold = lmd->md_threshold;
        umd->max_size = lmd->md_max_size;
        umd->options = lmd->md_options;
        umd->user_ptr = lmd->md_user_ptr;
        lnet_eq2handle(&umd->eq_handle, lmd->md_eq);
}

int
lnet_md_validate(lnet_md_t *umd)
{
        if (umd->start == NULL && umd->length != 0) {
                CERROR("MD start pointer can not be NULL with length %u\n",
                       umd->length);
                return -EINVAL;
        }

        if ((umd->options & (LNET_MD_KIOV | LNET_MD_IOVEC)) != 0 &&
            umd->length > LNET_MAX_IOV) {
                CERROR("Invalid option: too many fragments %u, %d max\n",
                       umd->length, LNET_MAX_IOV);
                return -EINVAL;
        }

        return 0;
}

/**
 * Create a memory descriptor and attach it to a ME
 *
 * \param meh A handle for a ME to associate the new MD with.
 * \param umd Provides initial values for the user-visible parts of a MD.
 * Other than its use for initialization, there is no linkage between this
 * structure and the MD maintained by the LNet.
 * \param unlink A flag to indicate whether the MD is automatically unlinked
 * when it becomes inactive, either because the operation threshold drops to
 * zero or because the available memory becomes less than \a umd.max_size.
 * (Note that the check for unlinking a MD only occurs after the completion
 * of a successful operation on the MD.) The value LNET_UNLINK enables auto
 * unlinking; the value LNET_RETAIN disables it.
 * \param handle On successful returns, a handle to the newly created MD is
 * saved here. This handle can be used later in LNetMDUnlink().
 *
 * \retval 0       On success.
 * \retval -EINVAL If \a umd is not valid.
 * \retval -ENOMEM If new MD cannot be allocated.
 * \retval -ENOENT Either \a meh or \a umd.eq_handle does not point to a
 * valid object. Note that it's OK to supply a NULL \a umd.eq_handle by
 * calling LNetInvalidateHandle() on it.
 * \retval -EBUSY  If the ME pointed to by \a meh is already associated with
 * a MD.
 */
int
LNetMDAttach(lnet_handle_me_t meh, lnet_md_t umd,
             lnet_unlink_t unlink, lnet_handle_md_t *handle)
{
	CFS_LIST_HEAD	(matches);
	CFS_LIST_HEAD	(drops);
        lnet_me_t     *me;
        lnet_libmd_t  *md;
        int            rc;

        LASSERT (the_lnet.ln_init);
        LASSERT (the_lnet.ln_refcount > 0);

        if (lnet_md_validate(&umd) != 0)
                return -EINVAL;

        if ((umd.options & (LNET_MD_OP_GET | LNET_MD_OP_PUT)) == 0) {
                CERROR("Invalid option: no MD_OP set\n");
                return -EINVAL;
        }

        md = lnet_md_alloc(&umd);
        if (md == NULL)
                return -ENOMEM;

	rc = lnet_md_build(md, &umd, unlink);

	lnet_res_lock();
	if (rc != 0)
		goto failed;

        me = lnet_handle2me(&meh);
	if (me == NULL)
		rc = -ENOENT;
	else if (me->me_md != NULL)
                rc = -EBUSY;
	else
		rc = lnet_md_link(md, umd.eq_handle);

	if (rc != 0)
		goto failed;

	/* attach this MD to portal of ME and check if it matches any
	 * blocked msgs on this portal */
	lnet_ptl_attach_md(me, md, &matches, &drops);

	lnet_md2handle(handle, md);

	lnet_res_unlock();

	lnet_drop_delayed_msg_list(&drops, "Bad match");
	lnet_recv_delayed_msg_list(&matches);

	return 0;

 failed:
	lnet_md_free_locked(md);

	lnet_res_unlock();
	return rc;
}

/**
 * Create a "free floating" memory descriptor - a MD that is not associated
 * with a ME. Such MDs are usually used in LNetPut() and LNetGet() operations.
 *
 * \param umd,unlink See the discussion for LNetMDAttach().
 * \param handle On successful returns, a handle to the newly created MD is
 * saved here. This handle can be used later in LNetMDUnlink(), LNetPut(),
 * and LNetGet() operations.
 *
 * \retval 0       On success.
 * \retval -EINVAL If \a umd is not valid.
 * \retval -ENOMEM If new MD cannot be allocated.
 * \retval -ENOENT \a umd.eq_handle does not point to a valid EQ. Note that
 * it's OK to supply a NULL \a umd.eq_handle by calling
 * LNetInvalidateHandle() on it.
 */
int
LNetMDBind(lnet_md_t umd, lnet_unlink_t unlink, lnet_handle_md_t *handle)
{
        lnet_libmd_t  *md;
        int            rc;

        LASSERT (the_lnet.ln_init);
        LASSERT (the_lnet.ln_refcount > 0);

        if (lnet_md_validate(&umd) != 0)
                return -EINVAL;

        if ((umd.options & (LNET_MD_OP_GET | LNET_MD_OP_PUT)) != 0) {
                CERROR("Invalid option: GET|PUT illegal on active MDs\n");
                return -EINVAL;
        }

        md = lnet_md_alloc(&umd);
        if (md == NULL)
                return -ENOMEM;

	rc = lnet_md_build(md, &umd, unlink);

	lnet_res_lock();
	if (rc != 0)
		goto failed;

	rc = lnet_md_link(md, umd.eq_handle);
	if (rc != 0)
		goto failed;

	lnet_md2handle(handle, md);

	lnet_res_unlock();
	return 0;

 failed:
	lnet_md_free_locked(md);

	lnet_res_unlock();
	return rc;
}

/**
 * Unlink the memory descriptor from any ME it may be linked to and release
 * the internal resources associated with it.
 *
 * This function does not free the memory region associated with the MD;
 * i.e., the memory the user allocated for this MD. If the ME associated with
 * this MD is not NULL and was created with auto unlink enabled, the ME is
 * unlinked as well (see LNetMEAttach()).
 *
 * Explicitly unlinking a MD via this function call has the same behavior as
 * a MD that has been automatically unlinked, except that no LNET_EVENT_UNLINK
 * is generated in the latter case.
 *
 * An unlinked event can be reported in two ways:
 * - If there's no pending operations on the MD, it's unlinked immediately
 *   and an LNET_EVENT_UNLINK event is logged before this function returns.
 * - Otherwise, the MD is only marked for deletion when this function
 *   returns, and the unlinked event will be piggybacked on the event of
 *   the completion of the last operation by setting the unlinked field of
 *   the event. No dedicated LNET_EVENT_UNLINK event is generated.
 *
 * Note that in both cases the unlinked field of the event is always set; no
 * more event will happen on the MD after such an event is logged.
 *
 * \param mdh A handle for the MD to be unlinked.
 *
 * \retval 0       On success.
 * \retval -ENOENT If \a mdh does not point to a valid MD object.
 */
int
LNetMDUnlink (lnet_handle_md_t mdh)
{
        lnet_event_t     ev;
        lnet_libmd_t    *md;

        LASSERT (the_lnet.ln_init);
        LASSERT (the_lnet.ln_refcount > 0);

	lnet_res_lock();

	md = lnet_handle2md(&mdh);
	if (md == NULL) {
		lnet_res_unlock();
                return -ENOENT;
        }

        /* If the MD is busy, lnet_md_unlink just marks it for deletion, and
         * when the NAL is done, the completion event flags that the MD was
         * unlinked.  Otherwise, we enqueue an event now... */

        if (md->md_eq != NULL &&
            md->md_refcount == 0) {
                lnet_build_unlink_event(md, &ev);
		lnet_eq_enqueue_event(md->md_eq, &ev);
        }

        lnet_md_unlink(md);

	lnet_res_unlock();
	return 0;
}