git.oblomov.eu Git - linux-2.6/blob - net/sunrpc/sched.c

   1 /*
   2  * linux/net/sunrpc/sched.c
   3  *
   4  * Scheduling for synchronous and asynchronous RPC requests.
   5  *
   6  * Copyright (C) 1996 Olaf Kirch, <okir@monad.swb.de>
   7  *
   8  * TCP NFS related read + write fixes
   9  * (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
  10  */
  11
  12 #include <linux/module.h>
  13
  14 #include <linux/sched.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/slab.h>
  17 #include <linux/mempool.h>
  18 #include <linux/smp.h>
  19 #include <linux/smp_lock.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/mutex.h>
  22
  23 #include <linux/sunrpc/clnt.h>
  24
  25 #ifdef RPC_DEBUG
  26 #define RPCDBG_FACILITY         RPCDBG_SCHED
  27 #define RPC_TASK_MAGIC_ID       0xf00baa
  28 static int                      rpc_task_id;
  29 #endif
  30
  31 /*
  32  * RPC slabs and memory pools
  33  */
  34 #define RPC_BUFFER_MAXSIZE      (2048)
  35 #define RPC_BUFFER_POOLSIZE     (8)
  36 #define RPC_TASK_POOLSIZE       (8)
  37 static kmem_cache_t     *rpc_task_slabp __read_mostly;
  38 static kmem_cache_t     *rpc_buffer_slabp __read_mostly;
  39 static mempool_t        *rpc_task_mempool __read_mostly;
  40 static mempool_t        *rpc_buffer_mempool __read_mostly;
  41
  42 static void                     __rpc_default_timer(struct rpc_task *task);
  43 static void                     rpciod_killall(void);
  44 static void                     rpc_async_schedule(void *);
  45
  46 /*
  47  * RPC tasks sit here while waiting for conditions to improve.
  48  */
  49 static RPC_WAITQ(delay_queue, "delayq");
  50
  51 /*
  52  * All RPC tasks are linked into this list
  53  */
  54 static LIST_HEAD(all_tasks);
  55
  56 /*
  57  * rpciod-related stuff
  58  */
  59 static DEFINE_MUTEX(rpciod_mutex);
  60 static unsigned int             rpciod_users;
  61 struct workqueue_struct *rpciod_workqueue;
  62
  63 /*
  64  * Spinlock for other critical sections of code.
  65  */
  66 static DEFINE_SPINLOCK(rpc_sched_lock);
  67
  68 /*
  69  * Disable the timer for a given RPC task. Should be called with
  70  * queue->lock and bh_disabled in order to avoid races within
  71  * rpc_run_timer().
  72  */
  73 static inline void
  74 __rpc_disable_timer(struct rpc_task *task)
  75 {
  76         dprintk("RPC: %4d disabling timer\n", task->tk_pid);
  77         task->tk_timeout_fn = NULL;
  78         task->tk_timeout = 0;
  79 }
  80
  81 /*
  82  * Run a timeout function.
  83  * We use the callback in order to allow __rpc_wake_up_task()
  84  * and friends to disable the timer synchronously on SMP systems
  85  * without calling del_timer_sync(). The latter could cause a
  86  * deadlock if called while we're holding spinlocks...
  87  */
  88 static void rpc_run_timer(struct rpc_task *task)
  89 {
  90         void (*callback)(struct rpc_task *);
  91
  92         callback = task->tk_timeout_fn;
  93         task->tk_timeout_fn = NULL;
  94         if (callback && RPC_IS_QUEUED(task)) {
  95                 dprintk("RPC: %4d running timer\n", task->tk_pid);
  96                 callback(task);
  97         }
  98         smp_mb__before_clear_bit();
  99         clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
 100         smp_mb__after_clear_bit();
 101 }
 102
 103 /*
 104  * Set up a timer for the current task.
 105  */
 106 static inline void
 107 __rpc_add_timer(struct rpc_task *task, rpc_action timer)
 108 {
 109         if (!task->tk_timeout)
 110                 return;
 111
 112         dprintk("RPC: %4d setting alarm for %lu ms\n",
 113                         task->tk_pid, task->tk_timeout * 1000 / HZ);
 114
 115         if (timer)
 116                 task->tk_timeout_fn = timer;
 117         else
 118                 task->tk_timeout_fn = __rpc_default_timer;
 119         set_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate);
 120         mod_timer(&task->tk_timer, jiffies + task->tk_timeout);
 121 }
 122
 123 /*
 124  * Delete any timer for the current task. Because we use del_timer_sync(),
 125  * this function should never be called while holding queue->lock.
 126  */
 127 static void
 128 rpc_delete_timer(struct rpc_task *task)
 129 {
 130         if (RPC_IS_QUEUED(task))
 131                 return;
 132         if (test_and_clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate)) {
 133                 del_singleshot_timer_sync(&task->tk_timer);
 134                 dprintk("RPC: %4d deleting timer\n", task->tk_pid);
 135         }
 136 }
 137
 138 /*
 139  * Add new request to a priority queue.
 140  */
 141 static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue, struct rpc_task *task)
 142 {
 143         struct list_head *q;
 144         struct rpc_task *t;
 145
 146         INIT_LIST_HEAD(&task->u.tk_wait.links);
 147         q = &queue->tasks[task->tk_priority];
 148         if (unlikely(task->tk_priority > queue->maxpriority))
 149                 q = &queue->tasks[queue->maxpriority];
 150         list_for_each_entry(t, q, u.tk_wait.list) {
 151                 if (t->tk_cookie == task->tk_cookie) {
 152                         list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
 153                         return;
 154                 }
 155         }
 156         list_add_tail(&task->u.tk_wait.list, q);
 157 }
 158
 159 /*
 160  * Add new request to wait queue.
 161  *
 162  * Swapper tasks always get inserted at the head of the queue.
 163  * This should avoid many nasty memory deadlocks and hopefully
 164  * improve overall performance.
 165  * Everyone else gets appended to the queue to ensure proper FIFO behavior.
 166  */
 167 static void __rpc_add_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
 168 {
 169         BUG_ON (RPC_IS_QUEUED(task));
 170
 171         if (RPC_IS_PRIORITY(queue))
 172                 __rpc_add_wait_queue_priority(queue, task);
 173         else if (RPC_IS_SWAPPER(task))
 174                 list_add(&task->u.tk_wait.list, &queue->tasks[0]);
 175         else
 176                 list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
 177         task->u.tk_wait.rpc_waitq = queue;
 178         queue->qlen++;
 179         rpc_set_queued(task);
 180
 181         dprintk("RPC: %4d added to queue %p \"%s\"\n",
 182                                 task->tk_pid, queue, rpc_qname(queue));
 183 }
 184
 185 /*
 186  * Remove request from a priority queue.
 187  */
 188 static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
 189 {
 190         struct rpc_task *t;
 191
 192         if (!list_empty(&task->u.tk_wait.links)) {
 193                 t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
 194                 list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
 195                 list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
 196         }
 197         list_del(&task->u.tk_wait.list);
 198 }
 199
 200 /*
 201  * Remove request from queue.
 202  * Note: must be called with spin lock held.
 203  */
 204 static void __rpc_remove_wait_queue(struct rpc_task *task)
 205 {
 206         struct rpc_wait_queue *queue;
 207         queue = task->u.tk_wait.rpc_waitq;
 208
 209         if (RPC_IS_PRIORITY(queue))
 210                 __rpc_remove_wait_queue_priority(task);
 211         else
 212                 list_del(&task->u.tk_wait.list);
 213         queue->qlen--;
 214         dprintk("RPC: %4d removed from queue %p \"%s\"\n",
 215                                 task->tk_pid, queue, rpc_qname(queue));
 216 }
 217
 218 static inline void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
 219 {
 220         queue->priority = priority;
 221         queue->count = 1 << (priority * 2);
 222 }
 223
 224 static inline void rpc_set_waitqueue_cookie(struct rpc_wait_queue *queue, unsigned long cookie)
 225 {
 226         queue->cookie = cookie;
 227         queue->nr = RPC_BATCH_COUNT;
 228 }
 229
 230 static inline void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
 231 {
 232         rpc_set_waitqueue_priority(queue, queue->maxpriority);
 233         rpc_set_waitqueue_cookie(queue, 0);
 234 }
 235
 236 static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, int maxprio)
 237 {
 238         int i;
 239
 240         spin_lock_init(&queue->lock);
 241         for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
 242                 INIT_LIST_HEAD(&queue->tasks[i]);
 243         queue->maxpriority = maxprio;
 244         rpc_reset_waitqueue_priority(queue);
 245 #ifdef RPC_DEBUG
 246         queue->name = qname;
 247 #endif
 248 }
 249
 250 void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
 251 {
 252         __rpc_init_priority_wait_queue(queue, qname, RPC_PRIORITY_HIGH);
 253 }
 254
 255 void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
 256 {
 257         __rpc_init_priority_wait_queue(queue, qname, 0);
 258 }
 259 EXPORT_SYMBOL(rpc_init_wait_queue);
 260
 261 static int rpc_wait_bit_interruptible(void *word)
 262 {
 263         if (signal_pending(current))
 264                 return -ERESTARTSYS;
 265         schedule();
 266         return 0;
 267 }
 268
 269 /*
 270  * Mark an RPC call as having completed by clearing the 'active' bit
 271  */
 272 static inline void rpc_mark_complete_task(struct rpc_task *task)
 273 {
 274         rpc_clear_active(task);
 275         wake_up_bit(&task->tk_runstate, RPC_TASK_ACTIVE);
 276 }
 277
 278 /*
 279  * Allow callers to wait for completion of an RPC call
 280  */
 281 int __rpc_wait_for_completion_task(struct rpc_task *task, int (*action)(void *))
 282 {
 283         if (action == NULL)
 284                 action = rpc_wait_bit_interruptible;
 285         return wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
 286                         action, TASK_INTERRUPTIBLE);
 287 }
 288 EXPORT_SYMBOL(__rpc_wait_for_completion_task);
 289
 290 /*
 291  * Make an RPC task runnable.
 292  *
 293  * Note: If the task is ASYNC, this must be called with
 294  * the spinlock held to protect the wait queue operation.
 295  */
 296 static void rpc_make_runnable(struct rpc_task *task)
 297 {
 298         int do_ret;
 299
 300         BUG_ON(task->tk_timeout_fn);
 301         do_ret = rpc_test_and_set_running(task);
 302         rpc_clear_queued(task);
 303         if (do_ret)
 304                 return;
 305         if (RPC_IS_ASYNC(task)) {
 306                 int status;
 307
 308                 INIT_WORK(&task->u.tk_work, rpc_async_schedule, (void *)task);
 309                 status = queue_work(task->tk_workqueue, &task->u.tk_work);
 310                 if (status < 0) {
 311                         printk(KERN_WARNING "RPC: failed to add task to queue: error: %d!\n", status);
 312                         task->tk_status = status;
 313                         return;
 314                 }
 315         } else
 316                 wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
 317 }
 318
 319 /*
 320  * Prepare for sleeping on a wait queue.
 321  * By always appending tasks to the list we ensure FIFO behavior.
 322  * NB: An RPC task will only receive interrupt-driven events as long
 323  * as it's on a wait queue.
 324  */
 325 static void __rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
 326                         rpc_action action, rpc_action timer)
 327 {
 328         dprintk("RPC: %4d sleep_on(queue \"%s\" time %ld)\n", task->tk_pid,
 329                                 rpc_qname(q), jiffies);
 330
 331         if (!RPC_IS_ASYNC(task) && !RPC_IS_ACTIVATED(task)) {
 332                 printk(KERN_ERR "RPC: Inactive synchronous task put to sleep!\n");
 333                 return;
 334         }
 335
 336         /* Mark the task as being activated if so needed */
 337         rpc_set_active(task);
 338
 339         __rpc_add_wait_queue(q, task);
 340
 341         BUG_ON(task->tk_callback != NULL);
 342         task->tk_callback = action;
 343         __rpc_add_timer(task, timer);
 344 }
 345
 346 void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
 347                                 rpc_action action, rpc_action timer)
 348 {
 349         /*
 350          * Protect the queue operations.
 351          */
 352         spin_lock_bh(&q->lock);
 353         __rpc_sleep_on(q, task, action, timer);
 354         spin_unlock_bh(&q->lock);
 355 }
 356
 357 /**
 358  * __rpc_do_wake_up_task - wake up a single rpc_task
 359  * @task: task to be woken up
 360  *
 361  * Caller must hold queue->lock, and have cleared the task queued flag.
 362  */
 363 static void __rpc_do_wake_up_task(struct rpc_task *task)
 364 {
 365         dprintk("RPC: %4d __rpc_wake_up_task (now %ld)\n", task->tk_pid, jiffies);
 366
 367 #ifdef RPC_DEBUG
 368         BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
 369 #endif
 370         /* Has the task been executed yet? If not, we cannot wake it up! */
 371         if (!RPC_IS_ACTIVATED(task)) {
 372                 printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
 373                 return;
 374         }
 375
 376         __rpc_disable_timer(task);
 377         __rpc_remove_wait_queue(task);
 378
 379         rpc_make_runnable(task);
 380
 381         dprintk("RPC:      __rpc_wake_up_task done\n");
 382 }
 383
 384 /*
 385  * Wake up the specified task
 386  */
 387 static void __rpc_wake_up_task(struct rpc_task *task)
 388 {
 389         if (rpc_start_wakeup(task)) {
 390                 if (RPC_IS_QUEUED(task))
 391                         __rpc_do_wake_up_task(task);
 392                 rpc_finish_wakeup(task);
 393         }
 394 }
 395
 396 /*
 397  * Default timeout handler if none specified by user
 398  */
 399 static void
 400 __rpc_default_timer(struct rpc_task *task)
 401 {
 402         dprintk("RPC: %d timeout (default timer)\n", task->tk_pid);
 403         task->tk_status = -ETIMEDOUT;
 404         rpc_wake_up_task(task);
 405 }
 406
 407 /*
 408  * Wake up the specified task
 409  */
 410 void rpc_wake_up_task(struct rpc_task *task)
 411 {
 412         if (rpc_start_wakeup(task)) {
 413                 if (RPC_IS_QUEUED(task)) {
 414                         struct rpc_wait_queue *queue = task->u.tk_wait.rpc_waitq;
 415
 416                         spin_lock_bh(&queue->lock);
 417                         __rpc_do_wake_up_task(task);
 418                         spin_unlock_bh(&queue->lock);
 419                 }
 420                 rpc_finish_wakeup(task);
 421         }
 422 }
 423
 424 /*
 425  * Wake up the next task on a priority queue.
 426  */
 427 static struct rpc_task * __rpc_wake_up_next_priority(struct rpc_wait_queue *queue)
 428 {
 429         struct list_head *q;
 430         struct rpc_task *task;
 431
 432         /*
 433          * Service a batch of tasks from a single cookie.
 434          */
 435         q = &queue->tasks[queue->priority];
 436         if (!list_empty(q)) {
 437                 task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
 438                 if (queue->cookie == task->tk_cookie) {
 439                         if (--queue->nr)
 440                                 goto out;
 441                         list_move_tail(&task->u.tk_wait.list, q);
 442                 }
 443                 /*
 444                  * Check if we need to switch queues.
 445                  */
 446                 if (--queue->count)
 447                         goto new_cookie;
 448         }
 449
 450         /*
 451          * Service the next queue.
 452          */
 453         do {
 454                 if (q == &queue->tasks[0])
 455                         q = &queue->tasks[queue->maxpriority];
 456                 else
 457                         q = q - 1;
 458                 if (!list_empty(q)) {
 459                         task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
 460                         goto new_queue;
 461                 }
 462         } while (q != &queue->tasks[queue->priority]);
 463
 464         rpc_reset_waitqueue_priority(queue);
 465         return NULL;
 466
 467 new_queue:
 468         rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
 469 new_cookie:
 470         rpc_set_waitqueue_cookie(queue, task->tk_cookie);
 471 out:
 472         __rpc_wake_up_task(task);
 473         return task;
 474 }
 475
 476 /*
 477  * Wake up the next task on the wait queue.
 478  */
 479 struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
 480 {
 481         struct rpc_task *task = NULL;
 482
 483         dprintk("RPC:      wake_up_next(%p \"%s\")\n", queue, rpc_qname(queue));
 484         spin_lock_bh(&queue->lock);
 485         if (RPC_IS_PRIORITY(queue))
 486                 task = __rpc_wake_up_next_priority(queue);
 487         else {
 488                 task_for_first(task, &queue->tasks[0])
 489                         __rpc_wake_up_task(task);
 490         }
 491         spin_unlock_bh(&queue->lock);
 492
 493         return task;
 494 }
 495
 496 /**
 497  * rpc_wake_up - wake up all rpc_tasks
 498  * @queue: rpc_wait_queue on which the tasks are sleeping
 499  *
 500  * Grabs queue->lock
 501  */
 502 void rpc_wake_up(struct rpc_wait_queue *queue)
 503 {
 504         struct rpc_task *task, *next;
 505         struct list_head *head;
 506
 507         spin_lock_bh(&queue->lock);
 508         head = &queue->tasks[queue->maxpriority];
 509         for (;;) {
 510                 list_for_each_entry_safe(task, next, head, u.tk_wait.list)
 511                         __rpc_wake_up_task(task);
 512                 if (head == &queue->tasks[0])
 513                         break;
 514                 head--;
 515         }
 516         spin_unlock_bh(&queue->lock);
 517 }
 518
 519 /**
 520  * rpc_wake_up_status - wake up all rpc_tasks and set their status value.
 521  * @queue: rpc_wait_queue on which the tasks are sleeping
 522  * @status: status value to set
 523  *
 524  * Grabs queue->lock
 525  */
 526 void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
 527 {
 528         struct rpc_task *task, *next;
 529         struct list_head *head;
 530
 531         spin_lock_bh(&queue->lock);
 532         head = &queue->tasks[queue->maxpriority];
 533         for (;;) {
 534                 list_for_each_entry_safe(task, next, head, u.tk_wait.list) {
 535                         task->tk_status = status;
 536                         __rpc_wake_up_task(task);
 537                 }
 538                 if (head == &queue->tasks[0])
 539                         break;
 540                 head--;
 541         }
 542         spin_unlock_bh(&queue->lock);
 543 }
 544
 545 static void __rpc_atrun(struct rpc_task *task)
 546 {
 547         rpc_wake_up_task(task);
 548 }
 549
 550 /*
 551  * Run a task at a later time
 552  */
 553 void rpc_delay(struct rpc_task *task, unsigned long delay)
 554 {
 555         task->tk_timeout = delay;
 556         rpc_sleep_on(&delay_queue, task, NULL, __rpc_atrun);
 557 }
 558
 559 /*
 560  * Helper to call task->tk_ops->rpc_call_prepare
 561  */
 562 static void rpc_prepare_task(struct rpc_task *task)
 563 {
 564         task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
 565 }
 566
 567 /*
 568  * Helper that calls task->tk_ops->rpc_call_done if it exists
 569  */
 570 void rpc_exit_task(struct rpc_task *task)
 571 {
 572         task->tk_action = NULL;
 573         if (task->tk_ops->rpc_call_done != NULL) {
 574                 task->tk_ops->rpc_call_done(task, task->tk_calldata);
 575                 if (task->tk_action != NULL) {
 576                         WARN_ON(RPC_ASSASSINATED(task));
 577                         /* Always release the RPC slot and buffer memory */
 578                         xprt_release(task);
 579                 }
 580         }
 581 }
 582 EXPORT_SYMBOL(rpc_exit_task);
 583
 584 /*
 585  * This is the RPC `scheduler' (or rather, the finite state machine).
 586  */
 587 static int __rpc_execute(struct rpc_task *task)
 588 {
 589         int             status = 0;
 590
 591         dprintk("RPC: %4d rpc_execute flgs %x\n",
 592                                 task->tk_pid, task->tk_flags);
 593
 594         BUG_ON(RPC_IS_QUEUED(task));
 595
 596         for (;;) {
 597                 /*
 598                  * Garbage collection of pending timers...
 599                  */
 600                 rpc_delete_timer(task);
 601
 602                 /*
 603                  * Execute any pending callback.
 604                  */
 605                 if (RPC_DO_CALLBACK(task)) {
 606                         /* Define a callback save pointer */
 607                         void (*save_callback)(struct rpc_task *);
 608
 609                         /*
 610                          * If a callback exists, save it, reset it,
 611                          * call it.
 612                          * The save is needed to stop from resetting
 613                          * another callback set within the callback handler
 614                          * - Dave
 615                          */
 616                         save_callback=task->tk_callback;
 617                         task->tk_callback=NULL;
 618                         lock_kernel();
 619                         save_callback(task);
 620                         unlock_kernel();
 621                 }
 622
 623                 /*
 624                  * Perform the next FSM step.
 625                  * tk_action may be NULL when the task has been killed
 626                  * by someone else.
 627                  */
 628                 if (!RPC_IS_QUEUED(task)) {
 629                         if (task->tk_action == NULL)
 630                                 break;
 631                         lock_kernel();
 632                         task->tk_action(task);
 633                         unlock_kernel();
 634                 }
 635
 636                 /*
 637                  * Lockless check for whether task is sleeping or not.
 638                  */
 639                 if (!RPC_IS_QUEUED(task))
 640                         continue;
 641                 rpc_clear_running(task);
 642                 if (RPC_IS_ASYNC(task)) {
 643                         /* Careful! we may have raced... */
 644                         if (RPC_IS_QUEUED(task))
 645                                 return 0;
 646                         if (rpc_test_and_set_running(task))
 647                                 return 0;
 648                         continue;
 649                 }
 650
 651                 /* sync task: sleep here */
 652                 dprintk("RPC: %4d sync task going to sleep\n", task->tk_pid);
 653                 /* Note: Caller should be using rpc_clnt_sigmask() */
 654                 status = out_of_line_wait_on_bit(&task->tk_runstate,
 655                                 RPC_TASK_QUEUED, rpc_wait_bit_interruptible,
 656                                 TASK_INTERRUPTIBLE);
 657                 if (status == -ERESTARTSYS) {
 658                         /*
 659                          * When a sync task receives a signal, it exits with
 660                          * -ERESTARTSYS. In order to catch any callbacks that
 661                          * clean up after sleeping on some queue, we don't
 662                          * break the loop here, but go around once more.
 663                          */
 664                         dprintk("RPC: %4d got signal\n", task->tk_pid);
 665                         task->tk_flags |= RPC_TASK_KILLED;
 666                         rpc_exit(task, -ERESTARTSYS);
 667                         rpc_wake_up_task(task);
 668                 }
 669                 rpc_set_running(task);
 670                 dprintk("RPC: %4d sync task resuming\n", task->tk_pid);
 671         }
 672
 673         dprintk("RPC: %4d, return %d, status %d\n", task->tk_pid, status, task->tk_status);
 674         /* Wake up anyone who is waiting for task completion */
 675         rpc_mark_complete_task(task);
 676         /* Release all resources associated with the task */
 677         rpc_release_task(task);
 678         return status;
 679 }
 680
 681 /*
 682  * User-visible entry point to the scheduler.
 683  *
 684  * This may be called recursively if e.g. an async NFS task updates
 685  * the attributes and finds that dirty pages must be flushed.
 686  * NOTE: Upon exit of this function the task is guaranteed to be
 687  *       released. In particular note that tk_release() will have
 688  *       been called, so your task memory may have been freed.
 689  */
 690 int
 691 rpc_execute(struct rpc_task *task)
 692 {
 693         rpc_set_active(task);
 694         rpc_set_running(task);
 695         return __rpc_execute(task);
 696 }
 697
 698 static void rpc_async_schedule(void *arg)
 699 {
 700         __rpc_execute((struct rpc_task *)arg);
 701 }
 702
 703 /**
 704  * rpc_malloc - allocate an RPC buffer
 705  * @task: RPC task that will use this buffer
 706  * @size: requested byte size
 707  *
 708  * We try to ensure that some NFS reads and writes can always proceed
 709  * by using a mempool when allocating 'small' buffers.
 710  * In order to avoid memory starvation triggering more writebacks of
 711  * NFS requests, we use GFP_NOFS rather than GFP_KERNEL.
 712  */
 713 void * rpc_malloc(struct rpc_task *task, size_t size)
 714 {
 715         struct rpc_rqst *req = task->tk_rqstp;
 716         gfp_t   gfp;
 717
 718         if (task->tk_flags & RPC_TASK_SWAPPER)
 719                 gfp = GFP_ATOMIC;
 720         else
 721                 gfp = GFP_NOFS;
 722
 723         if (size > RPC_BUFFER_MAXSIZE) {
 724                 req->rq_buffer = kmalloc(size, gfp);
 725                 if (req->rq_buffer)
 726                         req->rq_bufsize = size;
 727         } else {
 728                 req->rq_buffer = mempool_alloc(rpc_buffer_mempool, gfp);
 729                 if (req->rq_buffer)
 730                         req->rq_bufsize = RPC_BUFFER_MAXSIZE;
 731         }
 732         return req->rq_buffer;
 733 }
 734
 735 /**
 736  * rpc_free - free buffer allocated via rpc_malloc
 737  * @task: RPC task with a buffer to be freed
 738  *
 739  */
 740 void rpc_free(struct rpc_task *task)
 741 {
 742         struct rpc_rqst *req = task->tk_rqstp;
 743
 744         if (req->rq_buffer) {
 745                 if (req->rq_bufsize == RPC_BUFFER_MAXSIZE)
 746                         mempool_free(req->rq_buffer, rpc_buffer_mempool);
 747                 else
 748                         kfree(req->rq_buffer);
 749                 req->rq_buffer = NULL;
 750                 req->rq_bufsize = 0;
 751         }
 752 }
 753
 754 /*
 755  * Creation and deletion of RPC task structures
 756  */
 757 void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, int flags, const struct rpc_call_ops *tk_ops, void *calldata)
 758 {
 759         memset(task, 0, sizeof(*task));
 760         init_timer(&task->tk_timer);
 761         task->tk_timer.data     = (unsigned long) task;
 762         task->tk_timer.function = (void (*)(unsigned long)) rpc_run_timer;
 763         atomic_set(&task->tk_count, 1);
 764         task->tk_client = clnt;
 765         task->tk_flags  = flags;
 766         task->tk_ops = tk_ops;
 767         if (tk_ops->rpc_call_prepare != NULL)
 768                 task->tk_action = rpc_prepare_task;
 769         task->tk_calldata = calldata;
 770
 771         /* Initialize retry counters */
 772         task->tk_garb_retry = 2;
 773         task->tk_cred_retry = 2;
 774
 775         task->tk_priority = RPC_PRIORITY_NORMAL;
 776         task->tk_cookie = (unsigned long)current;
 777
 778         /* Initialize workqueue for async tasks */
 779         task->tk_workqueue = rpciod_workqueue;
 780
 781         if (clnt) {
 782                 atomic_inc(&clnt->cl_users);
 783                 if (clnt->cl_softrtry)
 784                         task->tk_flags |= RPC_TASK_SOFT;
 785                 if (!clnt->cl_intr)
 786                         task->tk_flags |= RPC_TASK_NOINTR;
 787         }
 788
 789 #ifdef RPC_DEBUG
 790         task->tk_magic = RPC_TASK_MAGIC_ID;
 791         task->tk_pid = rpc_task_id++;
 792 #endif
 793         /* Add to global list of all tasks */
 794         spin_lock(&rpc_sched_lock);
 795         list_add_tail(&task->tk_task, &all_tasks);
 796         spin_unlock(&rpc_sched_lock);
 797
 798         BUG_ON(task->tk_ops == NULL);
 799
 800         /* starting timestamp */
 801         task->tk_start = jiffies;
 802
 803         dprintk("RPC: %4d new task procpid %d\n", task->tk_pid,
 804                                 current->pid);
 805 }
 806
 807 static struct rpc_task *
 808 rpc_alloc_task(void)
 809 {
 810         return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS);
 811 }
 812
 813 static void rpc_free_task(struct rpc_task *task)
 814 {
 815         dprintk("RPC: %4d freeing task\n", task->tk_pid);
 816         mempool_free(task, rpc_task_mempool);
 817 }
 818
 819 /*
 820  * Create a new task for the specified client.  We have to
 821  * clean up after an allocation failure, as the client may
 822  * have specified "oneshot".
 823  */
 824 struct rpc_task *rpc_new_task(struct rpc_clnt *clnt, int flags, const struct rpc_call_ops *tk_ops, void *calldata)
 825 {
 826         struct rpc_task *task;
 827
 828         task = rpc_alloc_task();
 829         if (!task)
 830                 goto cleanup;
 831
 832         rpc_init_task(task, clnt, flags, tk_ops, calldata);
 833
 834         dprintk("RPC: %4d allocated task\n", task->tk_pid);
 835         task->tk_flags |= RPC_TASK_DYNAMIC;
 836 out:
 837         return task;
 838
 839 cleanup:
 840         /* Check whether to release the client */
 841         if (clnt) {
 842                 printk("rpc_new_task: failed, users=%d, oneshot=%d\n",
 843                         atomic_read(&clnt->cl_users), clnt->cl_oneshot);
 844                 atomic_inc(&clnt->cl_users); /* pretend we were used ... */
 845                 rpc_release_client(clnt);
 846         }
 847         goto out;
 848 }
 849
 850 void rpc_release_task(struct rpc_task *task)
 851 {
 852         const struct rpc_call_ops *tk_ops = task->tk_ops;
 853         void *calldata = task->tk_calldata;
 854
 855 #ifdef RPC_DEBUG
 856         BUG_ON(task->tk_magic != RPC_TASK_MAGIC_ID);
 857 #endif
 858         if (!atomic_dec_and_test(&task->tk_count))
 859                 return;
 860         dprintk("RPC: %4d release task\n", task->tk_pid);
 861
 862         /* Remove from global task list */
 863         spin_lock(&rpc_sched_lock);
 864         list_del(&task->tk_task);
 865         spin_unlock(&rpc_sched_lock);
 866
 867         BUG_ON (RPC_IS_QUEUED(task));
 868
 869         /* Synchronously delete any running timer */
 870         rpc_delete_timer(task);
 871
 872         /* Release resources */
 873         if (task->tk_rqstp)
 874                 xprt_release(task);
 875         if (task->tk_msg.rpc_cred)
 876                 rpcauth_unbindcred(task);
 877         if (task->tk_client) {
 878                 rpc_release_client(task->tk_client);
 879                 task->tk_client = NULL;
 880         }
 881
 882 #ifdef RPC_DEBUG
 883         task->tk_magic = 0;
 884 #endif
 885         if (task->tk_flags & RPC_TASK_DYNAMIC)
 886                 rpc_free_task(task);
 887         if (tk_ops->rpc_release)
 888                 tk_ops->rpc_release(calldata);
 889 }
 890
 891 /**
 892  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 893  * @clnt: pointer to RPC client
 894  * @flags: RPC flags
 895  * @ops: RPC call ops
 896  * @data: user call data
 897  */
 898 struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
 899                                         const struct rpc_call_ops *ops,
 900                                         void *data)
 901 {
 902         struct rpc_task *task;
 903         task = rpc_new_task(clnt, flags, ops, data);
 904         if (task == NULL) {
 905                 if (ops->rpc_release != NULL)
 906                         ops->rpc_release(data);
 907                 return ERR_PTR(-ENOMEM);
 908         }
 909         atomic_inc(&task->tk_count);
 910         rpc_execute(task);
 911         return task;
 912 }
 913 EXPORT_SYMBOL(rpc_run_task);
 914
 915 /*
 916  * Kill all tasks for the given client.
 917  * XXX: kill their descendants as well?
 918  */
 919 void rpc_killall_tasks(struct rpc_clnt *clnt)
 920 {
 921         struct rpc_task *rovr;
 922         struct list_head *le;
 923
 924         dprintk("RPC:      killing all tasks for client %p\n", clnt);
 925
 926         /*
 927          * Spin lock all_tasks to prevent changes...
 928          */
 929         spin_lock(&rpc_sched_lock);
 930         alltask_for_each(rovr, le, &all_tasks) {
 931                 if (! RPC_IS_ACTIVATED(rovr))
 932                         continue;
 933                 if (!clnt || rovr->tk_client == clnt) {
 934                         rovr->tk_flags |= RPC_TASK_KILLED;
 935                         rpc_exit(rovr, -EIO);
 936                         rpc_wake_up_task(rovr);
 937                 }
 938         }
 939         spin_unlock(&rpc_sched_lock);
 940 }
 941
 942 static DECLARE_MUTEX_LOCKED(rpciod_running);
 943
 944 static void rpciod_killall(void)
 945 {
 946         unsigned long flags;
 947
 948         while (!list_empty(&all_tasks)) {
 949                 clear_thread_flag(TIF_SIGPENDING);
 950                 rpc_killall_tasks(NULL);
 951                 flush_workqueue(rpciod_workqueue);
 952                 if (!list_empty(&all_tasks)) {
 953                         dprintk("rpciod_killall: waiting for tasks to exit\n");
 954                         yield();
 955                 }
 956         }
 957
 958         spin_lock_irqsave(&current->sighand->siglock, flags);
 959         recalc_sigpending();
 960         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 961 }
 962
 963 /*
 964  * Start up the rpciod process if it's not already running.
 965  */
 966 int
 967 rpciod_up(void)
 968 {
 969         struct workqueue_struct *wq;
 970         int error = 0;
 971
 972         mutex_lock(&rpciod_mutex);
 973         dprintk("rpciod_up: users %d\n", rpciod_users);
 974         rpciod_users++;
 975         if (rpciod_workqueue)
 976                 goto out;
 977         /*
 978          * If there's no pid, we should be the first user.
 979          */
 980         if (rpciod_users > 1)
 981                 printk(KERN_WARNING "rpciod_up: no workqueue, %d users??\n", rpciod_users);
 982         /*
 983          * Create the rpciod thread and wait for it to start.
 984          */
 985         error = -ENOMEM;
 986         wq = create_workqueue("rpciod");
 987         if (wq == NULL) {
 988                 printk(KERN_WARNING "rpciod_up: create workqueue failed, error=%d\n", error);
 989                 rpciod_users--;
 990                 goto out;
 991         }
 992         rpciod_workqueue = wq;
 993         error = 0;
 994 out:
 995         mutex_unlock(&rpciod_mutex);
 996         return error;
 997 }
 998
 999 void
1000 rpciod_down(void)
1001 {
1002         mutex_lock(&rpciod_mutex);
1003         dprintk("rpciod_down sema %d\n", rpciod_users);
1004         if (rpciod_users) {
1005                 if (--rpciod_users)
1006                         goto out;
1007         } else
1008                 printk(KERN_WARNING "rpciod_down: no users??\n");
1009
1010         if (!rpciod_workqueue) {
1011                 dprintk("rpciod_down: Nothing to do!\n");
1012                 goto out;
1013         }
1014         rpciod_killall();
1015
1016         destroy_workqueue(rpciod_workqueue);
1017         rpciod_workqueue = NULL;
1018  out:
1019         mutex_unlock(&rpciod_mutex);
1020 }
1021
1022 #ifdef RPC_DEBUG
1023 void rpc_show_tasks(void)
1024 {
1025         struct list_head *le;
1026         struct rpc_task *t;
1027
1028         spin_lock(&rpc_sched_lock);
1029         if (list_empty(&all_tasks)) {
1030                 spin_unlock(&rpc_sched_lock);
1031                 return;
1032         }
1033         printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
1034                 "-rpcwait -action- ---ops--\n");
1035         alltask_for_each(t, le, &all_tasks) {
1036                 const char *rpc_waitq = "none";
1037
1038                 if (RPC_IS_QUEUED(t))
1039                         rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
1040
1041                 printk("%05d %04d %04x %06d %8p %6d %8p %08ld %8s %8p %8p\n",
1042                         t->tk_pid,
1043                         (t->tk_msg.rpc_proc ? t->tk_msg.rpc_proc->p_proc : -1),
1044                         t->tk_flags, t->tk_status,
1045                         t->tk_client,
1046                         (t->tk_client ? t->tk_client->cl_prog : 0),
1047                         t->tk_rqstp, t->tk_timeout,
1048                         rpc_waitq,
1049                         t->tk_action, t->tk_ops);
1050         }
1051         spin_unlock(&rpc_sched_lock);
1052 }
1053 #endif
1054
1055 void
1056 rpc_destroy_mempool(void)
1057 {
1058         if (rpc_buffer_mempool)
1059                 mempool_destroy(rpc_buffer_mempool);
1060         if (rpc_task_mempool)
1061                 mempool_destroy(rpc_task_mempool);
1062         if (rpc_task_slabp && kmem_cache_destroy(rpc_task_slabp))
1063                 printk(KERN_INFO "rpc_task: not all structures were freed\n");
1064         if (rpc_buffer_slabp && kmem_cache_destroy(rpc_buffer_slabp))
1065                 printk(KERN_INFO "rpc_buffers: not all structures were freed\n");
1066 }
1067
1068 int
1069 rpc_init_mempool(void)
1070 {
1071         rpc_task_slabp = kmem_cache_create("rpc_tasks",
1072                                              sizeof(struct rpc_task),
1073                                              0, SLAB_HWCACHE_ALIGN,
1074                                              NULL, NULL);
1075         if (!rpc_task_slabp)
1076                 goto err_nomem;
1077         rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
1078                                              RPC_BUFFER_MAXSIZE,
1079                                              0, SLAB_HWCACHE_ALIGN,
1080                                              NULL, NULL);
1081         if (!rpc_buffer_slabp)
1082                 goto err_nomem;
1083         rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
1084                                                     rpc_task_slabp);
1085         if (!rpc_task_mempool)
1086                 goto err_nomem;
1087         rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
1088                                                       rpc_buffer_slabp);
1089         if (!rpc_buffer_mempool)
1090                 goto err_nomem;
1091         return 0;
1092 err_nomem:
1093         rpc_destroy_mempool();
1094         return -ENOMEM;
1095 }