libcfs/include/libcfs/user-lock.h

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