libcfs/include/libcfs/user-lock.h

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * GPL HEADER START
   5  *
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License version 2 for more details (a copy is included
  16  * in the LICENSE file that accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * version 2 along with this program; If not, see
  20  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  21  *
  22  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  23  * CA 95054 USA or visit www.sun.com if you need additional information or
  24  * have any questions.
  25  *
  26  * GPL HEADER END
  27  */
  28 /*
  29  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  30  * Use is subject to license terms.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * libcfs/include/libcfs/user-lock.h
  37  *
  38  * Author: Nikita Danilov <nikita@clusterfs.com>
  39  */
  40
  41 #ifndef __LIBCFS_USER_LOCK_H__
  42 #define __LIBCFS_USER_LOCK_H__
  43
  44 #ifndef __LIBCFS_LIBCFS_H__
  45 #error Do not #include this file directly. #include <libcfs/libcfs.h> instead
  46 #endif
  47
  48 /* Implementations of portable synchronization APIs for liblustre */
  49
  50 /*
  51  * liblustre is single-threaded, so most "synchronization" APIs are trivial.
  52  *
  53  * XXX Liang: There are several branches share lnet with b_hd_newconfig,
  54  * if we define lock APIs at here, there will be conflict with liblustre
  55  * in other branches.
  56  */
  57
  58 #ifndef __KERNEL__
  59
  60 /*
  61  * The userspace implementations of linux/spinlock.h vary; we just
  62  * include our own for all of them
  63  */
  64 #define __LINUX_SPINLOCK_H
  65
  66 /*
  67  * Optional debugging (magic stamping and checking ownership) can be added.
  68  */
  69
  70 /*
  71  * cfs_spin_lock
  72  *
  73  * - cfs_spin_lock_init(x)
  74  * - cfs_spin_lock(x)
  75  * - cfs_spin_unlock(x)
  76  * - cfs_spin_trylock(x)
  77  * - cfs_spin_lock_bh_init(x)
  78  * - cfs_spin_lock_bh(x)
  79  * - cfs_spin_unlock_bh(x)
  80  *
  81  * - cfs_spin_is_locked(x)
  82  * - cfs_spin_lock_irqsave(x, f)
  83  * - cfs_spin_unlock_irqrestore(x, f)
  84  *
  85  * No-op implementation.
  86  */
  87 struct cfs_spin_lock {int foo;};
  88
  89 typedef struct cfs_spin_lock cfs_spinlock_t;
  90
  91 #define CFS_SPIN_LOCK_UNLOCKED (cfs_spinlock_t) { }
  92 #define LASSERT_SPIN_LOCKED(lock) do {(void)sizeof(lock);} while(0)
  93 #define LINVRNT_SPIN_LOCKED(lock) do {(void)sizeof(lock);} while(0)
  94 #define LASSERT_SEM_LOCKED(sem) do {(void)sizeof(sem);} while(0)
  95 #define LASSERT_MUTEX_LOCKED(x) do {(void)sizeof(x);} while(0)
  96
  97 void cfs_spin_lock_init(cfs_spinlock_t *lock);
  98 void cfs_spin_lock(cfs_spinlock_t *lock);
  99 void cfs_spin_unlock(cfs_spinlock_t *lock);
 100 int cfs_spin_trylock(cfs_spinlock_t *lock);
 101 void cfs_spin_lock_bh_init(cfs_spinlock_t *lock);
 102 void cfs_spin_lock_bh(cfs_spinlock_t *lock);
 103 void cfs_spin_unlock_bh(cfs_spinlock_t *lock);
 104
 105 static inline int cfs_spin_is_locked(cfs_spinlock_t *l) {return 1;}
 106 static inline void cfs_spin_lock_irqsave(cfs_spinlock_t *l, unsigned long f){}
 107 static inline void cfs_spin_unlock_irqrestore(cfs_spinlock_t *l,
 108                                               unsigned long f){}
 109
 110 /*
 111  * Semaphore
 112  *
 113  * - cfs_sema_init(x, v)
 114  * - __down(x)
 115  * - __up(x)
 116  */
 117 typedef struct cfs_semaphore {
 118     int foo;
 119 } cfs_semaphore_t;
 120
 121 void cfs_sema_init(cfs_semaphore_t *s, int val);
 122 void __up(cfs_semaphore_t *s);
 123 void __down(cfs_semaphore_t *s);
 124 int __down_interruptible(cfs_semaphore_t *s);
 125
 126 #define CFS_DEFINE_SEMAPHORE(name)      cfs_semaphore_t name = { 1 }
 127
 128 #define cfs_up(s)                       __up(s)
 129 #define cfs_down(s)                     __down(s)
 130 #define cfs_down_interruptible(s)       __down_interruptible(s)
 131
 132 static inline int cfs_down_trylock(cfs_semaphore_t *sem)
 133 {
 134         return 0;
 135 }
 136
 137 /*
 138  * Completion:
 139  *
 140  * - cfs_init_completion_module(c)
 141  * - cfs_call_wait_handler(t)
 142  * - cfs_init_completion(c)
 143  * - cfs_complete(c)
 144  * - cfs_wait_for_completion(c)
 145  * - cfs_wait_for_completion_interruptible(c)
 146  */
 147 typedef struct {
 148         unsigned int done;
 149         cfs_waitq_t wait;
 150 } cfs_completion_t;
 151
 152 typedef int (*cfs_wait_handler_t) (int timeout);
 153 void cfs_init_completion_module(cfs_wait_handler_t handler);
 154 int  cfs_call_wait_handler(int timeout);
 155 void cfs_init_completion(cfs_completion_t *c);
 156 void cfs_complete(cfs_completion_t *c);
 157 void cfs_wait_for_completion(cfs_completion_t *c);
 158 int cfs_wait_for_completion_interruptible(cfs_completion_t *c);
 159
 160 #define CFS_COMPLETION_INITIALIZER(work) \
 161         { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
 162
 163 #define CFS_DECLARE_COMPLETION(work) \
 164         cfs_completion_t work = CFS_COMPLETION_INITIALIZER(work)
 165
 166 #define CFS_INIT_COMPLETION(x)      ((x).done = 0)
 167
 168
 169 /*
 170  * cfs_rw_semaphore:
 171  *
 172  * - cfs_init_rwsem(x)
 173  * - cfs_down_read(x)
 174  * - cfs_down_read_trylock(x)
 175  * - cfs_down_write(struct cfs_rw_semaphore *s);
 176  * - cfs_down_write_trylock(struct cfs_rw_semaphore *s);
 177  * - cfs_up_read(x)
 178  * - cfs_up_write(x)
 179  * - cfs_fini_rwsem(x)
 180  */
 181 typedef struct cfs_rw_semaphore {
 182         int foo;
 183 } cfs_rw_semaphore_t;
 184
 185 void cfs_init_rwsem(cfs_rw_semaphore_t *s);
 186 void cfs_down_read(cfs_rw_semaphore_t *s);
 187 int cfs_down_read_trylock(cfs_rw_semaphore_t *s);
 188 void cfs_down_write(cfs_rw_semaphore_t *s);
 189 int cfs_down_write_trylock(cfs_rw_semaphore_t *s);
 190 void cfs_up_read(cfs_rw_semaphore_t *s);
 191 void cfs_up_write(cfs_rw_semaphore_t *s);
 192 void cfs_fini_rwsem(cfs_rw_semaphore_t *s);
 193 #define CFS_DECLARE_RWSEM(name)  cfs_rw_semaphore_t name = { }
 194
 195 /*
 196  * read-write lock : Need to be investigated more!!
 197  * XXX nikita: for now, let rwlock_t to be identical to rw_semaphore
 198  *
 199  * - cfs_rwlock_init(x)
 200  * - cfs_read_lock(x)
 201  * - cfs_read_unlock(x)
 202  * - cfs_write_lock(x)
 203  * - cfs_write_unlock(x)
 204  * - cfs_write_lock_irqsave(x)
 205  * - cfs_write_unlock_irqrestore(x)
 206  * - cfs_read_lock_irqsave(x)
 207  * - cfs_read_unlock_irqrestore(x)
 208  */
 209 typedef cfs_rw_semaphore_t cfs_rwlock_t;
 210 #define CFS_RW_LOCK_UNLOCKED        (cfs_rwlock_t) { }
 211
 212 #define cfs_rwlock_init(pl)         cfs_init_rwsem(pl)
 213
 214 #define cfs_read_lock(l)            cfs_down_read(l)
 215 #define cfs_read_unlock(l)          cfs_up_read(l)
 216 #define cfs_write_lock(l)           cfs_down_write(l)
 217 #define cfs_write_unlock(l)         cfs_up_write(l)
 218
 219 static inline void
 220 cfs_write_lock_irqsave(cfs_rwlock_t *l, unsigned long f) { cfs_write_lock(l); }
 221 static inline void
 222 cfs_write_unlock_irqrestore(cfs_rwlock_t *l, unsigned long f) { cfs_write_unlock(l); }
 223
 224 static inline void
 225 cfs_read_lock_irqsave(cfs_rwlock_t *l, unsigned long f) { cfs_read_lock(l); }
 226 static inline void
 227 cfs_read_unlock_irqrestore(cfs_rwlock_t *l, unsigned long f) { cfs_read_unlock(l); }
 228
 229 /*
 230  * Atomic for single-threaded user-space
 231  */
 232 typedef struct { volatile int counter; } cfs_atomic_t;
 233
 234 #define CFS_ATOMIC_INIT(i) { (i) }
 235
 236 #define cfs_atomic_read(a) ((a)->counter)
 237 #define cfs_atomic_set(a,b) do {(a)->counter = b; } while (0)
 238 #define cfs_atomic_dec_and_test(a) ((--((a)->counter)) == 0)
 239 #define cfs_atomic_dec_and_lock(a,b) ((--((a)->counter)) == 0)
 240 #define cfs_atomic_inc(a)  (((a)->counter)++)
 241 #define cfs_atomic_dec(a)  do { (a)->counter--; } while (0)
 242 #define cfs_atomic_add(b,a)  do {(a)->counter += b;} while (0)
 243 #define cfs_atomic_add_return(n,a) ((a)->counter += n)
 244 #define cfs_atomic_inc_return(a) cfs_atomic_add_return(1,a)
 245 #define cfs_atomic_sub(b,a)  do {(a)->counter -= b;} while (0)
 246 #define cfs_atomic_sub_return(n,a) ((a)->counter -= n)
 247 #define cfs_atomic_dec_return(a)  cfs_atomic_sub_return(1,a)
 248 #define cfs_atomic_add_unless(v, a, u) \
 249         ((v)->counter != u ? (v)->counter += a : 0)
 250 #define cfs_atomic_inc_not_zero(v) cfs_atomic_add_unless((v), 1, 0)
 251
 252 #ifdef HAVE_LIBPTHREAD
 253 #include <pthread.h>
 254
 255 /*
 256  * Multi-threaded user space completion APIs
 257  */
 258
 259 typedef struct {
 260         int c_done;
 261         pthread_cond_t c_cond;
 262         pthread_mutex_t c_mut;
 263 } cfs_mt_completion_t;
 264
 265 void cfs_mt_init_completion(cfs_mt_completion_t *c);
 266 void cfs_mt_fini_completion(cfs_mt_completion_t *c);
 267 void cfs_mt_complete(cfs_mt_completion_t *c);
 268 void cfs_mt_wait_for_completion(cfs_mt_completion_t *c);
 269
 270 /*
 271  * Multi-threaded user space atomic APIs
 272  */
 273
 274 typedef struct { volatile int counter; } cfs_mt_atomic_t;
 275
 276 int cfs_mt_atomic_read(cfs_mt_atomic_t *a);
 277 void cfs_mt_atomic_set(cfs_mt_atomic_t *a, int b);
 278 int cfs_mt_atomic_dec_and_test(cfs_mt_atomic_t *a);
 279 void cfs_mt_atomic_inc(cfs_mt_atomic_t *a);
 280 void cfs_mt_atomic_dec(cfs_mt_atomic_t *a);
 281 void cfs_mt_atomic_add(int b, cfs_mt_atomic_t *a);
 282 void cfs_mt_atomic_sub(int b, cfs_mt_atomic_t *a);
 283
 284 #endif /* HAVE_LIBPTHREAD */
 285
 286 /**************************************************************************
 287  *
 288  * Mutex interface.
 289  *
 290  **************************************************************************/
 291 typedef struct cfs_semaphore cfs_mutex_t;
 292
 293 #define CFS_DEFINE_MUTEX(m) CFS_DEFINE_SEMAPHORE(m)
 294
 295 static inline void cfs_mutex_init(cfs_mutex_t *mutex)
 296 {
 297         cfs_sema_init(mutex, 1);
 298 }
 299
 300 static inline void cfs_mutex_lock(cfs_mutex_t *mutex)
 301 {
 302         cfs_down(mutex);
 303 }
 304
 305 static inline void cfs_mutex_unlock(cfs_mutex_t *mutex)
 306 {
 307         cfs_up(mutex);
 308 }
 309
 310 static inline int cfs_mutex_lock_interruptible(cfs_mutex_t *mutex)
 311 {
 312         return cfs_down_interruptible(mutex);
 313 }
 314
 315 /**
 316  * Try-lock this mutex.
 317  *
 318  * Note, return values are negation of what is expected from down_trylock() or
 319  * pthread_mutex_trylock().
 320  *
 321  * \retval 1 try-lock succeeded (lock acquired).
 322  * \retval 0 indicates lock contention.
 323  */
 324 static inline int cfs_mutex_trylock(cfs_mutex_t *mutex)
 325 {
 326         return !cfs_down_trylock(mutex);
 327 }
 328
 329 static inline void cfs_mutex_destroy(cfs_mutex_t *lock)
 330 {
 331 }
 332
 333 /*
 334  * This is for use in assertions _only_, i.e., this function should always
 335  * return 1.
 336  *
 337  * \retval 1 mutex is locked.
 338  *
 339  * \retval 0 mutex is not locked. This should never happen.
 340  */
 341 static inline int cfs_mutex_is_locked(cfs_mutex_t *lock)
 342 {
 343         return 1;
 344 }
 345
 346
 347 /**************************************************************************
 348  *
 349  * Lockdep "implementation". Also see lustre_compat25.h
 350  *
 351  **************************************************************************/
 352
 353 typedef struct cfs_lock_class_key {
 354         int foo;
 355 } cfs_lock_class_key_t;
 356
 357 static inline void cfs_lockdep_set_class(void *lock,
 358                                          cfs_lock_class_key_t *key)
 359 {
 360 }
 361
 362 static inline void cfs_lockdep_off(void)
 363 {
 364 }
 365
 366 static inline void cfs_lockdep_on(void)
 367 {
 368 }
 369
 370 #define cfs_mutex_lock_nested(mutex, subclass) cfs_mutex_lock(mutex)
 371 #define cfs_spin_lock_nested(lock, subclass) cfs_spin_lock(lock)
 372 #define cfs_down_read_nested(lock, subclass) cfs_down_read(lock)
 373 #define cfs_down_write_nested(lock, subclass) cfs_down_write(lock)
 374
 375
 376 /* !__KERNEL__ */
 377 #endif
 378
 379 /* __LIBCFS_USER_LOCK_H__ */
 380 #endif
 381 /*
 382  * Local variables:
 383  * c-indentation-style: "K&R"
 384  * c-basic-offset: 8
 385  * tab-width: 8
 386  * fill-column: 80
 387  * scroll-step: 1
 388  * End:
 389  */