[linux.git] / fs / fscache / operation.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* FS-Cache worker operation management routines
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * See Documentation/filesystems/caching/operations.rst
 */

#define FSCACHE_DEBUG_LEVEL OPERATION
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include "internal.h"

atomic_t fscache_op_debug_id;
EXPORT_SYMBOL(fscache_op_debug_id);

static void fscache_operation_dummy_cancel(struct fscache_operation *op)
{
}

/**
 * fscache_operation_init - Do basic initialisation of an operation
 * @op: The operation to initialise
 * @release: The release function to assign
 *
 * Do basic initialisation of an operation.  The caller must still set flags,
 * object and processor if needed.
 */
void fscache_operation_init(struct fscache_cookie *cookie,
			    struct fscache_operation *op,
			    fscache_operation_processor_t processor,
			    fscache_operation_cancel_t cancel,
			    fscache_operation_release_t release)
{
	INIT_WORK(&op->work, fscache_op_work_func);
	atomic_set(&op->usage, 1);
	op->state = FSCACHE_OP_ST_INITIALISED;
	op->debug_id = atomic_inc_return(&fscache_op_debug_id);
	op->processor = processor;
	op->cancel = cancel ?: fscache_operation_dummy_cancel;
	op->release = release;
	INIT_LIST_HEAD(&op->pend_link);
	fscache_stat(&fscache_n_op_initialised);
	trace_fscache_op(cookie, op, fscache_op_init);
}
EXPORT_SYMBOL(fscache_operation_init);

/**
 * fscache_enqueue_operation - Enqueue an operation for processing
 * @op: The operation to enqueue
 *
 * Enqueue an operation for processing by the FS-Cache thread pool.
 *
 * This will get its own ref on the object.
 */
void fscache_enqueue_operation(struct fscache_operation *op)
{
	struct fscache_cookie *cookie = op->object->cookie;
	
	_enter("{OBJ%x OP%x,%u}",
	       op->object->debug_id, op->debug_id, atomic_read(&op->usage));

	ASSERT(list_empty(&op->pend_link));
	ASSERT(op->processor != NULL);
	ASSERT(fscache_object_is_available(op->object));
	ASSERTCMP(atomic_read(&op->usage), >, 0);
	ASSERTIFCMP(op->state != FSCACHE_OP_ST_IN_PROGRESS,
		    op->state, ==,  FSCACHE_OP_ST_CANCELLED);

	fscache_stat(&fscache_n_op_enqueue);
	switch (op->flags & FSCACHE_OP_TYPE) {
	case FSCACHE_OP_ASYNC:
		trace_fscache_op(cookie, op, fscache_op_enqueue_async);
		_debug("queue async");
		atomic_inc(&op->usage);
		if (!queue_work(fscache_op_wq, &op->work))
			fscache_put_operation(op);
		break;
	case FSCACHE_OP_MYTHREAD:
		trace_fscache_op(cookie, op, fscache_op_enqueue_mythread);
		_debug("queue for caller's attention");
		break;
	default:
		pr_err("Unexpected op type %lx", op->flags);
		BUG();
		break;
	}
}
EXPORT_SYMBOL(fscache_enqueue_operation);

/*
 * start an op running
 */
static void fscache_run_op(struct fscache_object *object,
			   struct fscache_operation *op)
{
	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);

	op->state = FSCACHE_OP_ST_IN_PROGRESS;
	object->n_in_progress++;
	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
		wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
	if (op->processor)
		fscache_enqueue_operation(op);
	else
		trace_fscache_op(object->cookie, op, fscache_op_run);
	fscache_stat(&fscache_n_op_run);
}

/*
 * report an unexpected submission
 */
static void fscache_report_unexpected_submission(struct fscache_object *object,
						 struct fscache_operation *op,
						 const struct fscache_state *ostate)
{
	static bool once_only;
	struct fscache_operation *p;
	unsigned n;

	if (once_only)
		return;
	once_only = true;

	kdebug("unexpected submission OP%x [OBJ%x %s]",
	       op->debug_id, object->debug_id, object->state->name);
	kdebug("objstate=%s [%s]", object->state->name, ostate->name);
	kdebug("objflags=%lx", object->flags);
	kdebug("objevent=%lx [%lx]", object->events, object->event_mask);
	kdebug("ops=%u inp=%u exc=%u",
	       object->n_ops, object->n_in_progress, object->n_exclusive);

	if (!list_empty(&object->pending_ops)) {
		n = 0;
		list_for_each_entry(p, &object->pending_ops, pend_link) {
			ASSERTCMP(p->object, ==, object);
			kdebug("%p %p", op->processor, op->release);
			n++;
		}

		kdebug("n=%u", n);
	}

	dump_stack();
}

/*
 * submit an exclusive operation for an object
 * - other ops are excluded from running simultaneously with this one
 * - this gets any extra refs it needs on an op
 */
int fscache_submit_exclusive_op(struct fscache_object *object,
				struct fscache_operation *op)
{
	const struct fscache_state *ostate;
	unsigned long flags;
	int ret;

	_enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);

	trace_fscache_op(object->cookie, op, fscache_op_submit_ex);

	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
	ASSERTCMP(atomic_read(&op->usage), >, 0);

	spin_lock(&object->lock);
	ASSERTCMP(object->n_ops, >=, object->n_in_progress);
	ASSERTCMP(object->n_ops, >=, object->n_exclusive);
	ASSERT(list_empty(&op->pend_link));

	ostate = object->state;
	smp_rmb();

	op->state = FSCACHE_OP_ST_PENDING;
	flags = READ_ONCE(object->flags);
	if (unlikely(!(flags & BIT(FSCACHE_OBJECT_IS_LIVE)))) {
		fscache_stat(&fscache_n_op_rejected);
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	} else if (unlikely(fscache_cache_is_broken(object))) {
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -EIO;
	} else if (flags & BIT(FSCACHE_OBJECT_IS_AVAILABLE)) {
		op->object = object;
		object->n_ops++;
		object->n_exclusive++;	/* reads and writes must wait */

		if (object->n_in_progress > 0) {
			atomic_inc(&op->usage);
			list_add_tail(&op->pend_link, &object->pending_ops);
			fscache_stat(&fscache_n_op_pend);
		} else if (!list_empty(&object->pending_ops)) {
			atomic_inc(&op->usage);
			list_add_tail(&op->pend_link, &object->pending_ops);
			fscache_stat(&fscache_n_op_pend);
			fscache_start_operations(object);
		} else {
			ASSERTCMP(object->n_in_progress, ==, 0);
			fscache_run_op(object, op);
		}

		/* need to issue a new write op after this */
		clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
		ret = 0;
	} else if (flags & BIT(FSCACHE_OBJECT_IS_LOOKED_UP)) {
		op->object = object;
		object->n_ops++;
		object->n_exclusive++;	/* reads and writes must wait */
		atomic_inc(&op->usage);
		list_add_tail(&op->pend_link, &object->pending_ops);
		fscache_stat(&fscache_n_op_pend);
		ret = 0;
	} else if (flags & BIT(FSCACHE_OBJECT_KILLED_BY_CACHE)) {
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	} else {
		fscache_report_unexpected_submission(object, op, ostate);
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	}

	spin_unlock(&object->lock);
	return ret;
}

/*
 * submit an operation for an object
 * - objects may be submitted only in the following states:
 *   - during object creation (write ops may be submitted)
 *   - whilst the object is active
 *   - after an I/O error incurred in one of the two above states (op rejected)
 * - this gets any extra refs it needs on an op
 */
int fscache_submit_op(struct fscache_object *object,
		      struct fscache_operation *op)
{
	const struct fscache_state *ostate;
	unsigned long flags;
	int ret;

	_enter("{OBJ%x OP%x},{%u}",
	       object->debug_id, op->debug_id, atomic_read(&op->usage));

	trace_fscache_op(object->cookie, op, fscache_op_submit);

	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
	ASSERTCMP(atomic_read(&op->usage), >, 0);

	spin_lock(&object->lock);
	ASSERTCMP(object->n_ops, >=, object->n_in_progress);
	ASSERTCMP(object->n_ops, >=, object->n_exclusive);
	ASSERT(list_empty(&op->pend_link));

	ostate = object->state;
	smp_rmb();

	op->state = FSCACHE_OP_ST_PENDING;
	flags = READ_ONCE(object->flags);
	if (unlikely(!(flags & BIT(FSCACHE_OBJECT_IS_LIVE)))) {
		fscache_stat(&fscache_n_op_rejected);
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	} else if (unlikely(fscache_cache_is_broken(object))) {
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -EIO;
	} else if (flags & BIT(FSCACHE_OBJECT_IS_AVAILABLE)) {
		op->object = object;
		object->n_ops++;

		if (object->n_exclusive > 0) {
			atomic_inc(&op->usage);
			list_add_tail(&op->pend_link, &object->pending_ops);
			fscache_stat(&fscache_n_op_pend);
		} else if (!list_empty(&object->pending_ops)) {
			atomic_inc(&op->usage);
			list_add_tail(&op->pend_link, &object->pending_ops);
			fscache_stat(&fscache_n_op_pend);
			fscache_start_operations(object);
		} else {
			ASSERTCMP(object->n_exclusive, ==, 0);
			fscache_run_op(object, op);
		}
		ret = 0;
	} else if (flags & BIT(FSCACHE_OBJECT_IS_LOOKED_UP)) {
		op->object = object;
		object->n_ops++;
		atomic_inc(&op->usage);
		list_add_tail(&op->pend_link, &object->pending_ops);
		fscache_stat(&fscache_n_op_pend);
		ret = 0;
	} else if (flags & BIT(FSCACHE_OBJECT_KILLED_BY_CACHE)) {
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	} else {
		fscache_report_unexpected_submission(object, op, ostate);
		ASSERT(!fscache_object_is_active(object));
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		ret = -ENOBUFS;
	}

	spin_unlock(&object->lock);
	return ret;
}

/*
 * queue an object for withdrawal on error, aborting all following asynchronous
 * operations
 */
void fscache_abort_object(struct fscache_object *object)
{
	_enter("{OBJ%x}", object->debug_id);

	fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
}

/*
 * Jump start the operation processing on an object.  The caller must hold
 * object->lock.
 */
void fscache_start_operations(struct fscache_object *object)
{
	struct fscache_operation *op;
	bool stop = false;

	while (!list_empty(&object->pending_ops) && !stop) {
		op = list_entry(object->pending_ops.next,
				struct fscache_operation, pend_link);

		if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) {
			if (object->n_in_progress > 0)
				break;
			stop = true;
		}
		list_del_init(&op->pend_link);
		fscache_run_op(object, op);

		/* the pending queue was holding a ref on the object */
		fscache_put_operation(op);
	}

	ASSERTCMP(object->n_in_progress, <=, object->n_ops);

	_debug("woke %d ops on OBJ%x",
	       object->n_in_progress, object->debug_id);
}

/*
 * cancel an operation that's pending on an object
 */
int fscache_cancel_op(struct fscache_operation *op,
		      bool cancel_in_progress_op)
{
	struct fscache_object *object = op->object;
	bool put = false;
	int ret;

	_enter("OBJ%x OP%x}", op->object->debug_id, op->debug_id);

	trace_fscache_op(object->cookie, op, fscache_op_cancel);

	ASSERTCMP(op->state, >=, FSCACHE_OP_ST_PENDING);
	ASSERTCMP(op->state, !=, FSCACHE_OP_ST_CANCELLED);
	ASSERTCMP(atomic_read(&op->usage), >, 0);

	spin_lock(&object->lock);

	ret = -EBUSY;
	if (op->state == FSCACHE_OP_ST_PENDING) {
		ASSERT(!list_empty(&op->pend_link));
		list_del_init(&op->pend_link);
		put = true;

		fscache_stat(&fscache_n_op_cancelled);
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
			object->n_exclusive--;
		if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
			wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
		ret = 0;
	} else if (op->state == FSCACHE_OP_ST_IN_PROGRESS && cancel_in_progress_op) {
		ASSERTCMP(object->n_in_progress, >, 0);
		if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
			object->n_exclusive--;
		object->n_in_progress--;
		if (object->n_in_progress == 0)
			fscache_start_operations(object);

		fscache_stat(&fscache_n_op_cancelled);
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;
		if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
			object->n_exclusive--;
		if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
			wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
		ret = 0;
	}

	if (put)
		fscache_put_operation(op);
	spin_unlock(&object->lock);
	_leave(" = %d", ret);
	return ret;
}

/*
 * Cancel all pending operations on an object
 */
void fscache_cancel_all_ops(struct fscache_object *object)
{
	struct fscache_operation *op;

	_enter("OBJ%x", object->debug_id);

	spin_lock(&object->lock);

	while (!list_empty(&object->pending_ops)) {
		op = list_entry(object->pending_ops.next,
				struct fscache_operation, pend_link);
		fscache_stat(&fscache_n_op_cancelled);
		list_del_init(&op->pend_link);

		trace_fscache_op(object->cookie, op, fscache_op_cancel_all);

		ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
		op->cancel(op);
		op->state = FSCACHE_OP_ST_CANCELLED;

		if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
			object->n_exclusive--;
		if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
			wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
		fscache_put_operation(op);
		cond_resched_lock(&object->lock);
	}

	spin_unlock(&object->lock);
	_leave("");
}

/*
 * Record the completion or cancellation of an in-progress operation.
 */
void fscache_op_complete(struct fscache_operation *op, bool cancelled)
{
	struct fscache_object *object = op->object;

	_enter("OBJ%x", object->debug_id);

	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
	ASSERTCMP(object->n_in_progress, >, 0);
	ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
		    object->n_exclusive, >, 0);
	ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
		    object->n_in_progress, ==, 1);

	spin_lock(&object->lock);

	if (!cancelled) {
		trace_fscache_op(object->cookie, op, fscache_op_completed);
		op->state = FSCACHE_OP_ST_COMPLETE;
	} else {
		op->cancel(op);
		trace_fscache_op(object->cookie, op, fscache_op_cancelled);
		op->state = FSCACHE_OP_ST_CANCELLED;
	}

	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
		object->n_exclusive--;
	object->n_in_progress--;
	if (object->n_in_progress == 0)
		fscache_start_operations(object);

	spin_unlock(&object->lock);
	_leave("");
}
EXPORT_SYMBOL(fscache_op_complete);

/*
 * release an operation
 * - queues pending ops if this is the last in-progress op
 */
void fscache_put_operation(struct fscache_operation *op)
{
	struct fscache_object *object;
	struct fscache_cache *cache;

	_enter("{OBJ%x OP%x,%d}",
	       op->object ? op->object->debug_id : 0,
	       op->debug_id, atomic_read(&op->usage));

	ASSERTCMP(atomic_read(&op->usage), >, 0);

	if (!atomic_dec_and_test(&op->usage))
		return;

	trace_fscache_op(op->object ? op->object->cookie : NULL, op, fscache_op_put);

	_debug("PUT OP");
	ASSERTIFCMP(op->state != FSCACHE_OP_ST_INITIALISED &&
		    op->state != FSCACHE_OP_ST_COMPLETE,
		    op->state, ==, FSCACHE_OP_ST_CANCELLED);

	fscache_stat(&fscache_n_op_release);

	if (op->release) {
		op->release(op);
		op->release = NULL;
	}
	op->state = FSCACHE_OP_ST_DEAD;

	object = op->object;
	if (likely(object)) {
		if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags))
			atomic_dec(&object->n_reads);
		if (test_bit(FSCACHE_OP_UNUSE_COOKIE, &op->flags))
			fscache_unuse_cookie(object);

		/* now... we may get called with the object spinlock held, so we
		 * complete the cleanup here only if we can immediately acquire the
		 * lock, and defer it otherwise */
		if (!spin_trylock(&object->lock)) {
			_debug("defer put");
			fscache_stat(&fscache_n_op_deferred_release);

			cache = object->cache;
			spin_lock(&cache->op_gc_list_lock);
			list_add_tail(&op->pend_link, &cache->op_gc_list);
			spin_unlock(&cache->op_gc_list_lock);
			schedule_work(&cache->op_gc);
			_leave(" [defer]");
			return;
		}

		ASSERTCMP(object->n_ops, >, 0);
		object->n_ops--;
		if (object->n_ops == 0)
			fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);

		spin_unlock(&object->lock);
	}

	kfree(op);
	_leave(" [done]");
}
EXPORT_SYMBOL(fscache_put_operation);

/*
 * garbage collect operations that have had their release deferred
 */
void fscache_operation_gc(struct work_struct *work)
{
	struct fscache_operation *op;
	struct fscache_object *object;
	struct fscache_cache *cache =
		container_of(work, struct fscache_cache, op_gc);
	int count = 0;

	_enter("");

	do {
		spin_lock(&cache->op_gc_list_lock);
		if (list_empty(&cache->op_gc_list)) {
			spin_unlock(&cache->op_gc_list_lock);
			break;
		}

		op = list_entry(cache->op_gc_list.next,
				struct fscache_operation, pend_link);
		list_del(&op->pend_link);
		spin_unlock(&cache->op_gc_list_lock);

		object = op->object;
		trace_fscache_op(object->cookie, op, fscache_op_gc);

		spin_lock(&object->lock);

		_debug("GC DEFERRED REL OBJ%x OP%x",
		       object->debug_id, op->debug_id);
		fscache_stat(&fscache_n_op_gc);

		ASSERTCMP(atomic_read(&op->usage), ==, 0);
		ASSERTCMP(op->state, ==, FSCACHE_OP_ST_DEAD);

		ASSERTCMP(object->n_ops, >, 0);
		object->n_ops--;
		if (object->n_ops == 0)
			fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);

		spin_unlock(&object->lock);
		kfree(op);

	} while (count++ < 20);

	if (!list_empty(&cache->op_gc_list))
		schedule_work(&cache->op_gc);

	_leave("");
}

/*
 * execute an operation using fs_op_wq to provide processing context -
 * the caller holds a ref to this object, so we don't need to hold one
 */
void fscache_op_work_func(struct work_struct *work)
{
	struct fscache_operation *op =
		container_of(work, struct fscache_operation, work);
	unsigned long start;

	_enter("{OBJ%x OP%x,%d}",
	       op->object->debug_id, op->debug_id, atomic_read(&op->usage));

	trace_fscache_op(op->object->cookie, op, fscache_op_work);

	ASSERT(op->processor != NULL);
	start = jiffies;
	op->processor(op);
	fscache_hist(fscache_ops_histogram, start);
	fscache_put_operation(op);

	_leave("");
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
952efe7b DH	2	/* FS-Cache worker operation management routines
	3	*
	4	* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells ([email protected])
	6	*
09eac7c5	7	* See Documentation/filesystems/caching/operations.rst
952efe7b DH	8	*/
	9
	10	#define FSCACHE_DEBUG_LEVEL OPERATION
	11	#include <linux/module.h>
440f0aff	12	#include <linux/seq_file.h>
5a0e3ad6	13	#include <linux/slab.h>
952efe7b DH	14	#include "internal.h"
	15
	16	atomic_t fscache_op_debug_id;
	17	EXPORT_SYMBOL(fscache_op_debug_id);
	18
d3b97ca4 DH	19	static void fscache_operation_dummy_cancel(struct fscache_operation *op)
	20	{
	21	}
	22
1339ec98 DH	23	/**
	24	* fscache_operation_init - Do basic initialisation of an operation
	25	* @op: The operation to initialise
	26	* @release: The release function to assign
	27	*
	28	* Do basic initialisation of an operation. The caller must still set flags,
	29	* object and processor if needed.
	30	*/
08c2e3d0 DH	31	void fscache_operation_init(struct fscache_cookie *cookie,
08c2e3d0 DH	32	struct fscache_operation *op,
1339ec98	33	fscache_operation_processor_t processor,
d3b97ca4	34	fscache_operation_cancel_t cancel,
1339ec98 DH	35	fscache_operation_release_t release)
	36	{
	37	INIT_WORK(&op->work, fscache_op_work_func);
	38	atomic_set(&op->usage, 1);
	39	op->state = FSCACHE_OP_ST_INITIALISED;
	40	op->debug_id = atomic_inc_return(&fscache_op_debug_id);
	41	op->processor = processor;
d3b97ca4	42	op->cancel = cancel ?: fscache_operation_dummy_cancel;
1339ec98 DH	43	op->release = release;
1339ec98 DH	44	INIT_LIST_HEAD(&op->pend_link);
03cdd0e4	45	fscache_stat(&fscache_n_op_initialised);
08c2e3d0	46	trace_fscache_op(cookie, op, fscache_op_init);
1339ec98 DH	47	}
	48	EXPORT_SYMBOL(fscache_operation_init);
	49
952efe7b DH	50	/**
	51	* fscache_enqueue_operation - Enqueue an operation for processing
	52	* @op: The operation to enqueue
	53	*
	54	* Enqueue an operation for processing by the FS-Cache thread pool.
	55	*
	56	* This will get its own ref on the object.
	57	*/
	58	void fscache_enqueue_operation(struct fscache_operation *op)
	59	{
08c2e3d0 DH	60	struct fscache_cookie *cookie = op->object->cookie;
08c2e3d0 DH	61
952efe7b DH	62	_enter("{OBJ%x OP%x,%u}",
	63	op->object->debug_id, op->debug_id, atomic_read(&op->usage));
	64
5753c441	65	ASSERT(list_empty(&op->pend_link));
952efe7b	66	ASSERT(op->processor != NULL);
493f7bc1	67	ASSERT(fscache_object_is_available(op->object));
952efe7b	68	ASSERTCMP(atomic_read(&op->usage), >, 0);
d0eb06af KKM	69	ASSERTIFCMP(op->state != FSCACHE_OP_ST_IN_PROGRESS,
d0eb06af KKM	70	op->state, ==, FSCACHE_OP_ST_CANCELLED);
952efe7b	71
5753c441 DH	72	fscache_stat(&fscache_n_op_enqueue);
5753c441 DH	73	switch (op->flags & FSCACHE_OP_TYPE) {
8af7c124	74	case FSCACHE_OP_ASYNC:
08c2e3d0	75	trace_fscache_op(cookie, op, fscache_op_enqueue_async);
8af7c124	76	_debug("queue async");
5753c441	77	atomic_inc(&op->usage);
8af7c124	78	if (!queue_work(fscache_op_wq, &op->work))
5753c441 DH	79	fscache_put_operation(op);
5753c441 DH	80	break;
5753c441	81	case FSCACHE_OP_MYTHREAD:
08c2e3d0	82	trace_fscache_op(cookie, op, fscache_op_enqueue_mythread);
5753c441 DH	83	_debug("queue for caller's attention");
	84	break;
	85	default:
36dfd116	86	pr_err("Unexpected op type %lx", op->flags);
5753c441 DH	87	BUG();
5753c441 DH	88	break;
952efe7b DH	89	}
	90	}
	91	EXPORT_SYMBOL(fscache_enqueue_operation);
	92
	93	/*
	94	* start an op running
	95	*/
	96	static void fscache_run_op(struct fscache_object *object,
	97	struct fscache_operation *op)
	98	{
9f10523f DH	99	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
	100
	101	op->state = FSCACHE_OP_ST_IN_PROGRESS;
952efe7b DH	102	object->n_in_progress++;
	103	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
	104	wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
	105	if (op->processor)
	106	fscache_enqueue_operation(op);
08c2e3d0 DH	107	else
08c2e3d0 DH	108	trace_fscache_op(object->cookie, op, fscache_op_run);
952efe7b DH	109	fscache_stat(&fscache_n_op_run);
	110	}
	111
3c305984 DH	112	/*
	113	* report an unexpected submission
	114	*/
	115	static void fscache_report_unexpected_submission(struct fscache_object *object,
	116	struct fscache_operation *op,
	117	const struct fscache_state *ostate)
	118	{
	119	static bool once_only;
	120	struct fscache_operation *p;
	121	unsigned n;
	122
	123	if (once_only)
	124	return;
	125	once_only = true;
	126
	127	kdebug("unexpected submission OP%x [OBJ%x %s]",
	128	op->debug_id, object->debug_id, object->state->name);
	129	kdebug("objstate=%s [%s]", object->state->name, ostate->name);
	130	kdebug("objflags=%lx", object->flags);
	131	kdebug("objevent=%lx [%lx]", object->events, object->event_mask);
	132	kdebug("ops=%u inp=%u exc=%u",
	133	object->n_ops, object->n_in_progress, object->n_exclusive);
	134
	135	if (!list_empty(&object->pending_ops)) {
	136	n = 0;
	137	list_for_each_entry(p, &object->pending_ops, pend_link) {
	138	ASSERTCMP(p->object, ==, object);
	139	kdebug("%p %p", op->processor, op->release);
	140	n++;
	141	}
	142
	143	kdebug("n=%u", n);
	144	}
	145
	146	dump_stack();
	147	}
	148
952efe7b DH	149	/*
	150	* submit an exclusive operation for an object
	151	* - other ops are excluded from running simultaneously with this one
	152	* - this gets any extra refs it needs on an op
	153	*/
	154	int fscache_submit_exclusive_op(struct fscache_object *object,
	155	struct fscache_operation *op)
	156	{
30ceec62 DH	157	const struct fscache_state *ostate;
30ceec62 DH	158	unsigned long flags;
8d76349d DH	159	int ret;
8d76349d DH	160
952efe7b DH	161	_enter("{OBJ%x OP%x},", object->debug_id, op->debug_id);
952efe7b DH	162
08c2e3d0 DH	163	trace_fscache_op(object->cookie, op, fscache_op_submit_ex);
08c2e3d0 DH	164
9f10523f DH	165	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
	166	ASSERTCMP(atomic_read(&op->usage), >, 0);
	167
952efe7b DH	168	spin_lock(&object->lock);
	169	ASSERTCMP(object->n_ops, >=, object->n_in_progress);
	170	ASSERTCMP(object->n_ops, >=, object->n_exclusive);
5753c441	171	ASSERT(list_empty(&op->pend_link));
952efe7b	172
30ceec62 DH	173	ostate = object->state;
	174	smp_rmb();
	175
9f10523f	176	op->state = FSCACHE_OP_ST_PENDING;
30ceec62 DH	177	flags = READ_ONCE(object->flags);
	178	if (unlikely(!(flags & BIT(FSCACHE_OBJECT_IS_LIVE)))) {
	179	fscache_stat(&fscache_n_op_rejected);
d3b97ca4	180	op->cancel(op);
30ceec62 DH	181	op->state = FSCACHE_OP_ST_CANCELLED;
	182	ret = -ENOBUFS;
	183	} else if (unlikely(fscache_cache_is_broken(object))) {
d3b97ca4	184	op->cancel(op);
30ceec62 DH	185	op->state = FSCACHE_OP_ST_CANCELLED;
	186	ret = -EIO;
	187	} else if (flags & BIT(FSCACHE_OBJECT_IS_AVAILABLE)) {
952efe7b DH	188	op->object = object;
	189	object->n_ops++;
	190	object->n_exclusive++; /* reads and writes must wait */
	191
9f10523f	192	if (object->n_in_progress > 0) {
952efe7b DH	193	atomic_inc(&op->usage);
	194	list_add_tail(&op->pend_link, &object->pending_ops);
	195	fscache_stat(&fscache_n_op_pend);
	196	} else if (!list_empty(&object->pending_ops)) {
	197	atomic_inc(&op->usage);
	198	list_add_tail(&op->pend_link, &object->pending_ops);
	199	fscache_stat(&fscache_n_op_pend);
	200	fscache_start_operations(object);
	201	} else {
	202	ASSERTCMP(object->n_in_progress, ==, 0);
	203	fscache_run_op(object, op);
	204	}
	205
	206	/* need to issue a new write op after this */
	207	clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
8d76349d	208	ret = 0;
30ceec62	209	} else if (flags & BIT(FSCACHE_OBJECT_IS_LOOKED_UP)) {
952efe7b DH	210	op->object = object;
	211	object->n_ops++;
	212	object->n_exclusive++; /* reads and writes must wait */
	213	atomic_inc(&op->usage);
	214	list_add_tail(&op->pend_link, &object->pending_ops);
	215	fscache_stat(&fscache_n_op_pend);
8d76349d	216	ret = 0;
6515d1db	217	} else if (flags & BIT(FSCACHE_OBJECT_KILLED_BY_CACHE)) {
d3b97ca4	218	op->cancel(op);
6515d1db DH	219	op->state = FSCACHE_OP_ST_CANCELLED;
6515d1db DH	220	ret = -ENOBUFS;
952efe7b	221	} else {
30ceec62	222	fscache_report_unexpected_submission(object, op, ostate);
d3b97ca4	223	op->cancel(op);
30ceec62 DH	224	op->state = FSCACHE_OP_ST_CANCELLED;
30ceec62 DH	225	ret = -ENOBUFS;
952efe7b DH	226	}
	227
	228	spin_unlock(&object->lock);
8d76349d	229	return ret;
952efe7b DH	230	}
952efe7b DH	231
952efe7b DH	232	/*
	233	* submit an operation for an object
	234	* - objects may be submitted only in the following states:
	235	* - during object creation (write ops may be submitted)
	236	* - whilst the object is active
	237	* - after an I/O error incurred in one of the two above states (op rejected)
	238	* - this gets any extra refs it needs on an op
	239	*/
	240	int fscache_submit_op(struct fscache_object *object,
	241	struct fscache_operation *op)
	242	{
caaef690	243	const struct fscache_state *ostate;
30ceec62	244	unsigned long flags;
952efe7b DH	245	int ret;
	246
	247	_enter("{OBJ%x OP%x},{%u}",
	248	object->debug_id, op->debug_id, atomic_read(&op->usage));
	249
08c2e3d0 DH	250	trace_fscache_op(object->cookie, op, fscache_op_submit);
08c2e3d0 DH	251
9f10523f	252	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_INITIALISED);
952efe7b DH	253	ASSERTCMP(atomic_read(&op->usage), >, 0);
	254
	255	spin_lock(&object->lock);
	256	ASSERTCMP(object->n_ops, >=, object->n_in_progress);
	257	ASSERTCMP(object->n_ops, >=, object->n_exclusive);
5753c441	258	ASSERT(list_empty(&op->pend_link));
952efe7b DH	259
	260	ostate = object->state;
	261	smp_rmb();
	262
9f10523f	263	op->state = FSCACHE_OP_ST_PENDING;
30ceec62 DH	264	flags = READ_ONCE(object->flags);
	265	if (unlikely(!(flags & BIT(FSCACHE_OBJECT_IS_LIVE)))) {
	266	fscache_stat(&fscache_n_op_rejected);
d3b97ca4	267	op->cancel(op);
30ceec62 DH	268	op->state = FSCACHE_OP_ST_CANCELLED;
	269	ret = -ENOBUFS;
	270	} else if (unlikely(fscache_cache_is_broken(object))) {
d3b97ca4	271	op->cancel(op);
30ceec62 DH	272	op->state = FSCACHE_OP_ST_CANCELLED;
	273	ret = -EIO;
	274	} else if (flags & BIT(FSCACHE_OBJECT_IS_AVAILABLE)) {
952efe7b DH	275	op->object = object;
	276	object->n_ops++;
	277
	278	if (object->n_exclusive > 0) {
	279	atomic_inc(&op->usage);
	280	list_add_tail(&op->pend_link, &object->pending_ops);
	281	fscache_stat(&fscache_n_op_pend);
	282	} else if (!list_empty(&object->pending_ops)) {
	283	atomic_inc(&op->usage);
	284	list_add_tail(&op->pend_link, &object->pending_ops);
	285	fscache_stat(&fscache_n_op_pend);
	286	fscache_start_operations(object);
	287	} else {
	288	ASSERTCMP(object->n_exclusive, ==, 0);
	289	fscache_run_op(object, op);
	290	}
	291	ret = 0;
30ceec62	292	} else if (flags & BIT(FSCACHE_OBJECT_IS_LOOKED_UP)) {
952efe7b DH	293	op->object = object;
	294	object->n_ops++;
	295	atomic_inc(&op->usage);
	296	list_add_tail(&op->pend_link, &object->pending_ops);
	297	fscache_stat(&fscache_n_op_pend);
	298	ret = 0;
6515d1db	299	} else if (flags & BIT(FSCACHE_OBJECT_KILLED_BY_CACHE)) {
d3b97ca4	300	op->cancel(op);
6515d1db DH	301	op->state = FSCACHE_OP_ST_CANCELLED;
6515d1db DH	302	ret = -ENOBUFS;
30ceec62	303	} else {
952efe7b DH	304	fscache_report_unexpected_submission(object, op, ostate);
952efe7b DH	305	ASSERT(!fscache_object_is_active(object));
d3b97ca4	306	op->cancel(op);
9f10523f	307	op->state = FSCACHE_OP_ST_CANCELLED;
952efe7b	308	ret = -ENOBUFS;
952efe7b DH	309	}
	310
	311	spin_unlock(&object->lock);
	312	return ret;
	313	}
	314
	315	/*
	316	* queue an object for withdrawal on error, aborting all following asynchronous
	317	* operations
	318	*/
	319	void fscache_abort_object(struct fscache_object *object)
	320	{
	321	_enter("{OBJ%x}", object->debug_id);
	322
	323	fscache_raise_event(object, FSCACHE_OBJECT_EV_ERROR);
	324	}
	325
	326	/*
dcfae32f DH	327	* Jump start the operation processing on an object. The caller must hold
dcfae32f DH	328	* object->lock.
952efe7b DH	329	*/
	330	void fscache_start_operations(struct fscache_object *object)
	331	{
	332	struct fscache_operation *op;
	333	bool stop = false;
	334
	335	while (!list_empty(&object->pending_ops) && !stop) {
	336	op = list_entry(object->pending_ops.next,
	337	struct fscache_operation, pend_link);
	338
	339	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags)) {
	340	if (object->n_in_progress > 0)
	341	break;
	342	stop = true;
	343	}
	344	list_del_init(&op->pend_link);
5753c441	345	fscache_run_op(object, op);
952efe7b DH	346
	347	/* the pending queue was holding a ref on the object */
	348	fscache_put_operation(op);
	349	}
	350
	351	ASSERTCMP(object->n_in_progress, <=, object->n_ops);
	352
	353	_debug("woke %d ops on OBJ%x",
	354	object->n_in_progress, object->debug_id);
	355	}
	356
5753c441 DH	357	/*
	358	* cancel an operation that's pending on an object
	359	*/
91c7fbbf	360	int fscache_cancel_op(struct fscache_operation *op,
418b7eb9	361	bool cancel_in_progress_op)
5753c441 DH	362	{
5753c441 DH	363	struct fscache_object *object = op->object;
418b7eb9	364	bool put = false;
5753c441 DH	365	int ret;
	366
	367	_enter("OBJ%x OP%x}", op->object->debug_id, op->debug_id);
	368
08c2e3d0 DH	369	trace_fscache_op(object->cookie, op, fscache_op_cancel);
08c2e3d0 DH	370
9f10523f DH	371	ASSERTCMP(op->state, >=, FSCACHE_OP_ST_PENDING);
	372	ASSERTCMP(op->state, !=, FSCACHE_OP_ST_CANCELLED);
	373	ASSERTCMP(atomic_read(&op->usage), >, 0);
	374
5753c441 DH	375	spin_lock(&object->lock);
	376
	377	ret = -EBUSY;
9f10523f DH	378	if (op->state == FSCACHE_OP_ST_PENDING) {
9f10523f DH	379	ASSERT(!list_empty(&op->pend_link));
5753c441	380	list_del_init(&op->pend_link);
418b7eb9	381	put = true;
d3b97ca4	382
418b7eb9	383	fscache_stat(&fscache_n_op_cancelled);
d3b97ca4	384	op->cancel(op);
418b7eb9 DH	385	op->state = FSCACHE_OP_ST_CANCELLED;
	386	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
	387	object->n_exclusive--;
	388	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
	389	wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
	390	ret = 0;
	391	} else if (op->state == FSCACHE_OP_ST_IN_PROGRESS && cancel_in_progress_op) {
73c04a47 DH	392	ASSERTCMP(object->n_in_progress, >, 0);
	393	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
	394	object->n_exclusive--;
	395	object->n_in_progress--;
	396	if (object->n_in_progress == 0)
	397	fscache_start_operations(object);
	398
418b7eb9	399	fscache_stat(&fscache_n_op_cancelled);
d3b97ca4	400	op->cancel(op);
9f10523f	401	op->state = FSCACHE_OP_ST_CANCELLED;
5753c441 DH	402	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
	403	object->n_exclusive--;
	404	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
	405	wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
5753c441 DH	406	ret = 0;
	407	}
	408
418b7eb9 DH	409	if (put)
418b7eb9 DH	410	fscache_put_operation(op);
5753c441 DH	411	spin_unlock(&object->lock);
	412	_leave(" = %d", ret);
	413	return ret;
	414	}
	415
ef778e7a DH	416	/*
	417	* Cancel all pending operations on an object
	418	*/
	419	void fscache_cancel_all_ops(struct fscache_object *object)
	420	{
	421	struct fscache_operation *op;
	422
	423	_enter("OBJ%x", object->debug_id);
	424
	425	spin_lock(&object->lock);
	426
	427	while (!list_empty(&object->pending_ops)) {
	428	op = list_entry(object->pending_ops.next,
	429	struct fscache_operation, pend_link);
	430	fscache_stat(&fscache_n_op_cancelled);
	431	list_del_init(&op->pend_link);
	432
08c2e3d0 DH	433	trace_fscache_op(object->cookie, op, fscache_op_cancel_all);
08c2e3d0 DH	434
ef778e7a	435	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_PENDING);
d3b97ca4	436	op->cancel(op);
ef778e7a DH	437	op->state = FSCACHE_OP_ST_CANCELLED;
	438
	439	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
	440	object->n_exclusive--;
	441	if (test_and_clear_bit(FSCACHE_OP_WAITING, &op->flags))
	442	wake_up_bit(&op->flags, FSCACHE_OP_WAITING);
	443	fscache_put_operation(op);
	444	cond_resched_lock(&object->lock);
	445	}
	446
	447	spin_unlock(&object->lock);
	448	_leave("");
	449	}
	450
9f10523f	451	/*
1f372dff	452	* Record the completion or cancellation of an in-progress operation.
9f10523f	453	*/
1f372dff	454	void fscache_op_complete(struct fscache_operation *op, bool cancelled)
9f10523f DH	455	{
	456	struct fscache_object *object = op->object;
	457
	458	_enter("OBJ%x", object->debug_id);
	459
	460	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_IN_PROGRESS);
	461	ASSERTCMP(object->n_in_progress, >, 0);
	462	ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
	463	object->n_exclusive, >, 0);
	464	ASSERTIFCMP(test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags),
	465	object->n_in_progress, ==, 1);
	466
	467	spin_lock(&object->lock);
	468
d3b97ca4	469	if (!cancelled) {
08c2e3d0	470	trace_fscache_op(object->cookie, op, fscache_op_completed);
d3b97ca4 DH	471	op->state = FSCACHE_OP_ST_COMPLETE;
	472	} else {
	473	op->cancel(op);
08c2e3d0	474	trace_fscache_op(object->cookie, op, fscache_op_cancelled);
d3b97ca4 DH	475	op->state = FSCACHE_OP_ST_CANCELLED;
d3b97ca4 DH	476	}
9f10523f DH	477
	478	if (test_bit(FSCACHE_OP_EXCLUSIVE, &op->flags))
	479	object->n_exclusive--;
	480	object->n_in_progress--;
	481	if (object->n_in_progress == 0)
	482	fscache_start_operations(object);
	483
	484	spin_unlock(&object->lock);
	485	_leave("");
	486	}
	487	EXPORT_SYMBOL(fscache_op_complete);
	488
952efe7b DH	489	/*
	490	* release an operation
	491	* - queues pending ops if this is the last in-progress op
	492	*/
	493	void fscache_put_operation(struct fscache_operation *op)
	494	{
	495	struct fscache_object *object;
	496	struct fscache_cache *cache;
	497
	498	_enter("{OBJ%x OP%x,%d}",
d0eb06af KKM	499	op->object ? op->object->debug_id : 0,
d0eb06af KKM	500	op->debug_id, atomic_read(&op->usage));
952efe7b DH	501
	502	ASSERTCMP(atomic_read(&op->usage), >, 0);
	503
	504	if (!atomic_dec_and_test(&op->usage))
	505	return;
	506
402cb8dd	507	trace_fscache_op(op->object ? op->object->cookie : NULL, op, fscache_op_put);
08c2e3d0	508
952efe7b	509	_debug("PUT OP");
a39caadf DH	510	ASSERTIFCMP(op->state != FSCACHE_OP_ST_INITIALISED &&
a39caadf DH	511	op->state != FSCACHE_OP_ST_COMPLETE,
9f10523f	512	op->state, ==, FSCACHE_OP_ST_CANCELLED);
952efe7b DH	513
	514	fscache_stat(&fscache_n_op_release);
	515
	516	if (op->release) {
	517	op->release(op);
	518	op->release = NULL;
	519	}
4a47132f	520	op->state = FSCACHE_OP_ST_DEAD;
952efe7b DH	521
952efe7b DH	522	object = op->object;
a39caadf DH	523	if (likely(object)) {
	524	if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags))
	525	atomic_dec(&object->n_reads);
	526	if (test_bit(FSCACHE_OP_UNUSE_COOKIE, &op->flags))
	527	fscache_unuse_cookie(object);
	528
	529	/* now... we may get called with the object spinlock held, so we
	530	* complete the cleanup here only if we can immediately acquire the
	531	* lock, and defer it otherwise */
	532	if (!spin_trylock(&object->lock)) {
	533	_debug("defer put");
	534	fscache_stat(&fscache_n_op_deferred_release);
	535
	536	cache = object->cache;
	537	spin_lock(&cache->op_gc_list_lock);
	538	list_add_tail(&op->pend_link, &cache->op_gc_list);
	539	spin_unlock(&cache->op_gc_list_lock);
	540	schedule_work(&cache->op_gc);
	541	_leave(" [defer]");
	542	return;
	543	}
952efe7b	544
a39caadf DH	545	ASSERTCMP(object->n_ops, >, 0);
	546	object->n_ops--;
	547	if (object->n_ops == 0)
	548	fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
952efe7b	549
a39caadf	550	spin_unlock(&object->lock);
952efe7b DH	551	}
952efe7b DH	552
952efe7b DH	553	kfree(op);
	554	_leave(" [done]");
	555	}
	556	EXPORT_SYMBOL(fscache_put_operation);
	557
	558	/*
	559	* garbage collect operations that have had their release deferred
	560	*/
	561	void fscache_operation_gc(struct work_struct *work)
	562	{
	563	struct fscache_operation *op;
	564	struct fscache_object *object;
	565	struct fscache_cache *cache =
	566	container_of(work, struct fscache_cache, op_gc);
	567	int count = 0;
	568
	569	_enter("");
	570
	571	do {
	572	spin_lock(&cache->op_gc_list_lock);
	573	if (list_empty(&cache->op_gc_list)) {
	574	spin_unlock(&cache->op_gc_list_lock);
	575	break;
	576	}
	577
	578	op = list_entry(cache->op_gc_list.next,
	579	struct fscache_operation, pend_link);
	580	list_del(&op->pend_link);
	581	spin_unlock(&cache->op_gc_list_lock);
	582
	583	object = op->object;
08c2e3d0 DH	584	trace_fscache_op(object->cookie, op, fscache_op_gc);
08c2e3d0 DH	585
9f10523f	586	spin_lock(&object->lock);
952efe7b DH	587
	588	_debug("GC DEFERRED REL OBJ%x OP%x",
	589	object->debug_id, op->debug_id);
	590	fscache_stat(&fscache_n_op_gc);
	591
	592	ASSERTCMP(atomic_read(&op->usage), ==, 0);
9f10523f	593	ASSERTCMP(op->state, ==, FSCACHE_OP_ST_DEAD);
952efe7b DH	594
	595	ASSERTCMP(object->n_ops, >, 0);
	596	object->n_ops--;
	597	if (object->n_ops == 0)
	598	fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
	599
	600	spin_unlock(&object->lock);
9f10523f	601	kfree(op);
952efe7b DH	602
	603	} while (count++ < 20);
	604
	605	if (!list_empty(&cache->op_gc_list))
	606	schedule_work(&cache->op_gc);
	607
	608	_leave("");
	609	}
	610
	611	/*
8af7c124 TH	612	* execute an operation using fs_op_wq to provide processing context -
8af7c124 TH	613	* the caller holds a ref to this object, so we don't need to hold one
952efe7b	614	*/
8af7c124	615	void fscache_op_work_func(struct work_struct *work)
952efe7b DH	616	{
952efe7b DH	617	struct fscache_operation *op =
8af7c124	618	container_of(work, struct fscache_operation, work);
952efe7b DH	619	unsigned long start;
	620
	621	_enter("{OBJ%x OP%x,%d}",
	622	op->object->debug_id, op->debug_id, atomic_read(&op->usage));
	623
08c2e3d0 DH	624	trace_fscache_op(op->object->cookie, op, fscache_op_work);
08c2e3d0 DH	625
952efe7b DH	626	ASSERT(op->processor != NULL);
	627	start = jiffies;
	628	op->processor(op);
	629	fscache_hist(fscache_ops_histogram, start);
8af7c124	630	fscache_put_operation(op);
952efe7b DH	631
	632	_leave("");
	633	}