drivers/staging/lustre/lustre/include/lustre_lib.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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2012, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * lustre/include/lustre_lib.h
  33  *
  34  * Basic Lustre library routines.
  35  */
  36
  37 #ifndef _LUSTRE_LIB_H
  38 #define _LUSTRE_LIB_H
  39
  40 /** \defgroup lib lib
  41  *
  42  * @{
  43  */
  44
  45 #include <linux/sched.h>
  46 #include <linux/signal.h>
  47 #include <linux/types.h>
  48 #include "../../include/linux/libcfs/libcfs.h"
  49 #include "lustre/lustre_idl.h"
  50 #include "lustre_ver.h"
  51 #include "lustre_cfg.h"
  52
  53 /* target.c */
  54 struct ptlrpc_request;
  55 struct obd_export;
  56 struct lu_target;
  57 struct l_wait_info;
  58 #include "lustre_ha.h"
  59 #include "lustre_net.h"
  60
  61 #define LI_POISON 0x5a5a5a5a
  62 #if BITS_PER_LONG > 32
  63 # define LL_POISON 0x5a5a5a5a5a5a5a5aL
  64 #else
  65 # define LL_POISON 0x5a5a5a5aL
  66 #endif
  67 #define LP_POISON ((void *)LL_POISON)
  68
  69 int target_pack_pool_reply(struct ptlrpc_request *req);
  70 int do_set_info_async(struct obd_import *imp,
  71                       int opcode, int version,
  72                       u32 keylen, void *key,
  73                       u32 vallen, void *val,
  74                       struct ptlrpc_request_set *set);
  75
  76 void target_send_reply(struct ptlrpc_request *req, int rc, int fail_id);
  77
  78 /*
  79  * l_wait_event is a flexible sleeping function, permitting simple caller
  80  * configuration of interrupt and timeout sensitivity along with actions to
  81  * be performed in the event of either exception.
  82  *
  83  * The first form of usage looks like this:
  84  *
  85  * struct l_wait_info lwi = LWI_TIMEOUT_INTR(timeout, timeout_handler,
  86  *                                         intr_handler, callback_data);
  87  * rc = l_wait_event(waitq, condition, &lwi);
  88  *
  89  * l_wait_event() makes the current process wait on 'waitq' until 'condition'
  90  * is TRUE or a "killable" signal (SIGTERM, SIKGILL, SIGINT) is pending.  It
  91  * returns 0 to signify 'condition' is TRUE, but if a signal wakes it before
  92  * 'condition' becomes true, it optionally calls the specified 'intr_handler'
  93  * if not NULL, and returns -EINTR.
  94  *
  95  * If a non-zero timeout is specified, signals are ignored until the timeout
  96  * has expired.  At this time, if 'timeout_handler' is not NULL it is called.
  97  * If it returns FALSE l_wait_event() continues to wait as described above with
  98  * signals enabled.  Otherwise it returns -ETIMEDOUT.
  99  *
 100  * LWI_INTR(intr_handler, callback_data) is shorthand for
 101  * LWI_TIMEOUT_INTR(0, NULL, intr_handler, callback_data)
 102  *
 103  * The second form of usage looks like this:
 104  *
 105  * struct l_wait_info lwi = LWI_TIMEOUT(timeout, timeout_handler);
 106  * rc = l_wait_event(waitq, condition, &lwi);
 107  *
 108  * This form is the same as the first except that it COMPLETELY IGNORES
 109  * SIGNALS.  The caller must therefore beware that if 'timeout' is zero, or if
 110  * 'timeout_handler' is not NULL and returns FALSE, then the ONLY thing that
 111  * can unblock the current process is 'condition' becoming TRUE.
 112  *
 113  * Another form of usage is:
 114  * struct l_wait_info lwi = LWI_TIMEOUT_INTERVAL(timeout, interval,
 115  *                                             timeout_handler);
 116  * rc = l_wait_event(waitq, condition, &lwi);
 117  * This is the same as previous case, but condition is checked once every
 118  * 'interval' jiffies (if non-zero).
 119  *
 120  * Subtle synchronization point: this macro does *not* necessary takes
 121  * wait-queue spin-lock before returning, and, hence, following idiom is safe
 122  * ONLY when caller provides some external locking:
 123  *
 124  *           Thread1                        Thread2
 125  *
 126  *   l_wait_event(&obj->wq, ....);                                     (1)
 127  *
 128  *                                  wake_up(&obj->wq):           (2)
 129  *                                       spin_lock(&q->lock);     (2.1)
 130  *                                       __wake_up_common(q, ...);     (2.2)
 131  *                                       spin_unlock(&q->lock, flags); (2.3)
 132  *
 133  *   kfree(obj);                                                  (3)
 134  *
 135  * As l_wait_event() may "short-cut" execution and return without taking
 136  * wait-queue spin-lock, some additional synchronization is necessary to
 137  * guarantee that step (3) can begin only after (2.3) finishes.
 138  *
 139  * XXX nikita: some ptlrpc daemon threads have races of that sort.
 140  *
 141  */
 142 static inline int back_to_sleep(void *arg)
 143 {
 144         return 0;
 145 }
 146
 147 #define LWI_ON_SIGNAL_NOOP ((void (*)(void *))(-1))
 148
 149 struct l_wait_info {
 150         long lwi_timeout;
 151         long lwi_interval;
 152         int         lwi_allow_intr;
 153         int  (*lwi_on_timeout)(void *);
 154         void (*lwi_on_signal)(void *);
 155         void  *lwi_cb_data;
 156 };
 157
 158 /* NB: LWI_TIMEOUT ignores signals completely */
 159 #define LWI_TIMEOUT(time, cb, data)          \
 160 ((struct l_wait_info) {                  \
 161         .lwi_timeout    = time,          \
 162         .lwi_on_timeout = cb,              \
 163         .lwi_cb_data    = data,          \
 164         .lwi_interval   = 0,                \
 165         .lwi_allow_intr = 0                  \
 166 })
 167
 168 #define LWI_TIMEOUT_INTERVAL(time, interval, cb, data)  \
 169 ((struct l_wait_info) {                          \
 170         .lwi_timeout    = time,                  \
 171         .lwi_on_timeout = cb,                      \
 172         .lwi_cb_data    = data,                  \
 173         .lwi_interval   = interval,                  \
 174         .lwi_allow_intr = 0                          \
 175 })
 176
 177 #define LWI_TIMEOUT_INTR(time, time_cb, sig_cb, data)   \
 178 ((struct l_wait_info) {                          \
 179         .lwi_timeout    = time,                  \
 180         .lwi_on_timeout = time_cb,                    \
 181         .lwi_on_signal  = sig_cb,                      \
 182         .lwi_cb_data    = data,                  \
 183         .lwi_interval   = 0,                        \
 184         .lwi_allow_intr = 0                          \
 185 })
 186
 187 #define LWI_TIMEOUT_INTR_ALL(time, time_cb, sig_cb, data)       \
 188 ((struct l_wait_info) {                                  \
 189         .lwi_timeout    = time,                          \
 190         .lwi_on_timeout = time_cb,                            \
 191         .lwi_on_signal  = sig_cb,                              \
 192         .lwi_cb_data    = data,                          \
 193         .lwi_interval   = 0,                                \
 194         .lwi_allow_intr = 1                                  \
 195 })
 196
 197 #define LWI_INTR(cb, data)  LWI_TIMEOUT_INTR(0, NULL, cb, data)
 198
 199 #define LUSTRE_FATAL_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) |         \
 200                            sigmask(SIGTERM) | sigmask(SIGQUIT) |        \
 201                            sigmask(SIGALRM))
 202
 203 /**
 204  * wait_queue_t of Linux (version < 2.6.34) is a FIFO list for exclusively
 205  * waiting threads, which is not always desirable because all threads will
 206  * be waken up again and again, even user only needs a few of them to be
 207  * active most time. This is not good for performance because cache can
 208  * be polluted by different threads.
 209  *
 210  * LIFO list can resolve this problem because we always wakeup the most
 211  * recent active thread by default.
 212  *
 213  * NB: please don't call non-exclusive & exclusive wait on the same
 214  * waitq if add_wait_queue_exclusive_head is used.
 215  */
 216 #define add_wait_queue_exclusive_head(waitq, link)              \
 217 {                                                               \
 218         unsigned long flags;                                    \
 219                                                                 \
 220         spin_lock_irqsave(&((waitq)->lock), flags);             \
 221         __add_wait_queue_exclusive(waitq, link);                \
 222         spin_unlock_irqrestore(&((waitq)->lock), flags);        \
 223 }
 224
 225 /*
 226  * wait for @condition to become true, but no longer than timeout, specified
 227  * by @info.
 228  */
 229 #define __l_wait_event(wq, condition, info, ret, l_add_wait)               \
 230 do {                                                                       \
 231         wait_queue_t __wait;                                             \
 232         long __timeout = info->lwi_timeout;                       \
 233         sigset_t   __blocked;                                         \
 234         int   __allow_intr = info->lwi_allow_intr;                           \
 235                                                                                \
 236         ret = 0;                                                               \
 237         if (condition)                                                   \
 238                 break;                                                   \
 239                                                                                \
 240         init_waitqueue_entry(&__wait, current);                                     \
 241         l_add_wait(&wq, &__wait);                                             \
 242                                                                                \
 243         /* Block all signals (just the non-fatal ones if no timeout). */       \
 244         if (info->lwi_on_signal && (__timeout == 0 || __allow_intr))   \
 245                 __blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS);             \
 246         else                                                               \
 247                 __blocked = cfs_block_sigsinv(0);                             \
 248                                                                                \
 249         for (;;) {                                                           \
 250                 if (condition)                                           \
 251                         break;                                           \
 252                                                                                \
 253                 set_current_state(TASK_INTERRUPTIBLE);                         \
 254                                                                                \
 255                 if (__timeout == 0) {                                     \
 256                         schedule();                                            \
 257                 } else {                                                       \
 258                         long interval = info->lwi_interval ?      \
 259                                              min_t(long,             \
 260                                                  info->lwi_interval, __timeout) : \
 261                                              __timeout;                 \
 262                         long remaining = schedule_timeout(interval);\
 263                         __timeout = cfs_time_sub(__timeout,                 \
 264                                             cfs_time_sub(interval, remaining));\
 265                         if (__timeout == 0) {                             \
 266                                 if (!info->lwi_on_timeout ||                  \
 267                                     info->lwi_on_timeout(info->lwi_cb_data)) { \
 268                                         ret = -ETIMEDOUT;                     \
 269                                         break;                           \
 270                                 }                                             \
 271                                 /* Take signals after the timeout expires. */  \
 272                                 if (info->lwi_on_signal)                       \
 273                                     (void)cfs_block_sigsinv(LUSTRE_FATAL_SIGS);\
 274                         }                                                     \
 275                 }                                                             \
 276                                                                                \
 277                 set_current_state(TASK_RUNNING);                               \
 278                                                                                \
 279                 if (condition)                                           \
 280                         break;                                           \
 281                 if (signal_pending(current)) {                              \
 282                         if (info->lwi_on_signal &&                   \
 283                             (__timeout == 0 || __allow_intr)) {         \
 284                                 if (info->lwi_on_signal != LWI_ON_SIGNAL_NOOP) \
 285                                         info->lwi_on_signal(info->lwi_cb_data);\
 286                                 ret = -EINTR;                             \
 287                                 break;                                   \
 288                         }                                                     \
 289                         /* We have to do this here because some signals */     \
 290                         /* are not blockable - ie from strace(1).       */     \
 291                         /* In these cases we want to schedule_timeout() */     \
 292                         /* again, because we don't want that to return  */     \
 293                         /* -EINTR when the RPC actually succeeded.      */     \
 294                         /* the recalc_sigpending() below will deliver the */     \
 295                         /* signal properly.                          */     \
 296                         cfs_clear_sigpending();                         \
 297                 }                                                             \
 298         }                                                                     \
 299                                                                                \
 300         cfs_restore_sigs(__blocked);                                       \
 301                                                                                \
 302         remove_wait_queue(&wq, &__wait);                                           \
 303 } while (0)
 304
 305 #define l_wait_event(wq, condition, info)                      \
 306 ({                                                            \
 307         int              __ret;                       \
 308         struct l_wait_info *__info = (info);                \
 309                                                                 \
 310         __l_wait_event(wq, condition, __info,              \
 311                        __ret, add_wait_queue);             \
 312         __ret;                                            \
 313 })
 314
 315 #define l_wait_event_exclusive(wq, condition, info)          \
 316 ({                                                            \
 317         int              __ret;                       \
 318         struct l_wait_info *__info = (info);                \
 319                                                                 \
 320         __l_wait_event(wq, condition, __info,              \
 321                        __ret, add_wait_queue_exclusive);         \
 322         __ret;                                            \
 323 })
 324
 325 #define l_wait_event_exclusive_head(wq, condition, info)        \
 326 ({                                                            \
 327         int              __ret;                       \
 328         struct l_wait_info *__info = (info);                \
 329                                                                 \
 330         __l_wait_event(wq, condition, __info,              \
 331                        __ret, add_wait_queue_exclusive_head);    \
 332         __ret;                                            \
 333 })
 334
 335 #define l_wait_condition(wq, condition)                  \
 336 ({                                                            \
 337         struct l_wait_info lwi = { 0 };                  \
 338         l_wait_event(wq, condition, &lwi);                    \
 339 })
 340
 341 #define l_wait_condition_exclusive(wq, condition)              \
 342 ({                                                            \
 343         struct l_wait_info lwi = { 0 };                  \
 344         l_wait_event_exclusive(wq, condition, &lwi);        \
 345 })
 346
 347 #define l_wait_condition_exclusive_head(wq, condition)    \
 348 ({                                                            \
 349         struct l_wait_info lwi = { 0 };                  \
 350         l_wait_event_exclusive_head(wq, condition, &lwi);       \
 351 })
 352
 353 #define LIBLUSTRE_CLIENT (0)
 354
 355 /** @} lib */
 356
 357 #endif /* _LUSTRE_LIB_H */