Commit 5853b4f0 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: only force kblockd unplugging from the schedule() path
  block: cleanup the block plug helper functions
  block, blk-sysfs: Use the variable directly instead of a function call
  block: move queue run on unplug to kblockd
  block: kill queue_sync_plugs()
  block: readd plug trace event
  block: add callback function for unplug notification
  block: add comment on why we save and disable interrupts in flush_plug_list()
  block: fixup block IO unplug trace call
  block: remove block_unplug_timer() trace point
  block: splice plug list to local context
parents a970f5d5 f6603783

block/blk-core.c

+46 −40
Original line number Diff line number Diff line
@@ -198,19 +198,6 @@ void blk_dump_rq_flags(struct request *rq, char *msg) 
}

EXPORT_SYMBOL(blk_dump_rq_flags);



/*

 * Make sure that plugs that were pending when this function was entered,

 * are now complete and requests pushed to the queue.

*/

static inline void queue_sync_plugs(struct request_queue *q)

{

	/*

	 * If the current process is plugged and has barriers submitted,

	 * we will livelock if we don't unplug first.

	 */

	blk_flush_plug(current);

}



static void blk_delay_work(struct work_struct *work)

{

	struct request_queue *q;
@@ -298,7 +285,6 @@ void blk_sync_queue(struct request_queue *q) 
{

	del_timer_sync(&q->timeout);

	cancel_delayed_work_sync(&q->delay_work);

	queue_sync_plugs(q);

}

EXPORT_SYMBOL(blk_sync_queue);
@@ -1311,7 +1297,15 @@ get_rq: 


	plug = current->plug;

	if (plug) {

		if (!plug->should_sort && !list_empty(&plug->list)) {

		/*

		 * If this is the first request added after a plug, fire

		 * of a plug trace. If others have been added before, check

		 * if we have multiple devices in this plug. If so, make a

		 * note to sort the list before dispatch.

		 */

		if (list_empty(&plug->list))

			trace_block_plug(q);

		else if (!plug->should_sort) {

			struct request *__rq;



			__rq = list_entry_rq(plug->list.prev);
@@ -2668,33 +2662,56 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) 
	return !(rqa->q <= rqb->q);

}



static void flush_plug_list(struct blk_plug *plug)

static void queue_unplugged(struct request_queue *q, unsigned int depth,

			    bool force_kblockd)

{

	trace_block_unplug_io(q, depth);

	__blk_run_queue(q, force_kblockd);



	if (q->unplugged_fn)

		q->unplugged_fn(q);

}



void blk_flush_plug_list(struct blk_plug *plug, bool force_kblockd)

{

	struct request_queue *q;

	unsigned long flags;

	struct request *rq;

	LIST_HEAD(list);

	unsigned int depth;



	BUG_ON(plug->magic != PLUG_MAGIC);



	if (list_empty(&plug->list))

		return;



	if (plug->should_sort)

		list_sort(NULL, &plug->list, plug_rq_cmp);

	list_splice_init(&plug->list, &list);



	if (plug->should_sort) {

		list_sort(NULL, &list, plug_rq_cmp);

		plug->should_sort = 0;

	}



	q = NULL;

	depth = 0;



	/*

	 * Save and disable interrupts here, to avoid doing it for every

	 * queue lock we have to take.

	 */

	local_irq_save(flags);

	while (!list_empty(&plug->list)) {

		rq = list_entry_rq(plug->list.next);

	while (!list_empty(&list)) {

		rq = list_entry_rq(list.next);

		list_del_init(&rq->queuelist);

		BUG_ON(!(rq->cmd_flags & REQ_ON_PLUG));

		BUG_ON(!rq->q);

		if (rq->q != q) {

			if (q) {

				__blk_run_queue(q, false);

				queue_unplugged(q, depth, force_kblockd);

				spin_unlock(q->queue_lock);

			}

			q = rq->q;

			depth = 0;

			spin_lock(q->queue_lock);

		}

		rq->cmd_flags &= ~REQ_ON_PLUG;
@@ -2706,38 +2723,27 @@ static void flush_plug_list(struct blk_plug *plug) 
			__elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH);

		else

			__elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE);



		depth++;

	}



	if (q) {

		__blk_run_queue(q, false);

		queue_unplugged(q, depth, force_kblockd);

		spin_unlock(q->queue_lock);

	}



	BUG_ON(!list_empty(&plug->list));

	local_irq_restore(flags);

}



static void __blk_finish_plug(struct task_struct *tsk, struct blk_plug *plug)

{

	flush_plug_list(plug);



	if (plug == tsk->plug)

		tsk->plug = NULL;

}

EXPORT_SYMBOL(blk_flush_plug_list);



void blk_finish_plug(struct blk_plug *plug)

{

	if (plug)

		__blk_finish_plug(current, plug);

}

EXPORT_SYMBOL(blk_finish_plug);

	blk_flush_plug_list(plug, false);



void __blk_flush_plug(struct task_struct *tsk, struct blk_plug *plug)

{

	__blk_finish_plug(tsk, plug);

	tsk->plug = plug;

	if (plug == current->plug)

		current->plug = NULL;

}

EXPORT_SYMBOL(__blk_flush_plug);

EXPORT_SYMBOL(blk_finish_plug);



int __init blk_dev_init(void)

{

block/blk-settings.c

+16 −0
Original line number Diff line number Diff line
@@ -790,6 +790,22 @@ void blk_queue_flush(struct request_queue *q, unsigned int flush) 
}

EXPORT_SYMBOL_GPL(blk_queue_flush);



/**

 * blk_queue_unplugged - register a callback for an unplug event

 * @q:		the request queue for the device

 * @fn:		the function to call

 *

 * Some stacked drivers may need to know when IO is dispatched on an

 * unplug event. By registrering a callback here, they will be notified

 * when someone flushes their on-stack queue plug. The function will be

 * called with the queue lock held.

 */

void blk_queue_unplugged(struct request_queue *q, unplugged_fn *fn)

{

	q->unplugged_fn = fn;

}

EXPORT_SYMBOL(blk_queue_unplugged);



static int __init blk_settings_init(void)

{

	blk_max_low_pfn = max_low_pfn - 1;

block/blk-sysfs.c

+1 −2
Original line number Diff line number Diff line
@@ -498,7 +498,6 @@ int blk_register_queue(struct gendisk *disk) 
{

	int ret;

	struct device *dev = disk_to_dev(disk);



	struct request_queue *q = disk->queue;



	if (WARN_ON(!q))
@@ -521,7 +520,7 @@ int blk_register_queue(struct gendisk *disk) 
	if (ret) {

		kobject_uevent(&q->kobj, KOBJ_REMOVE);

		kobject_del(&q->kobj);

		blk_trace_remove_sysfs(disk_to_dev(disk));

		blk_trace_remove_sysfs(dev);

		kobject_put(&dev->kobj);

		return ret;

	}

include/linux/blkdev.h

+6 −3
Original line number Diff line number Diff line
@@ -196,6 +196,7 @@ typedef void (request_fn_proc) (struct request_queue *q); 
typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);

typedef int (prep_rq_fn) (struct request_queue *, struct request *);

typedef void (unprep_rq_fn) (struct request_queue *, struct request *);

typedef void (unplugged_fn) (struct request_queue *);



struct bio_vec;

struct bvec_merge_data {
@@ -283,6 +284,7 @@ struct request_queue 
	rq_timed_out_fn		*rq_timed_out_fn;

	dma_drain_needed_fn	*dma_drain_needed;

	lld_busy_fn		*lld_busy_fn;

	unplugged_fn		*unplugged_fn;



	/*

	 * Dispatch queue sorting
@@ -841,6 +843,7 @@ extern void blk_queue_dma_alignment(struct request_queue *, int); 
extern void blk_queue_update_dma_alignment(struct request_queue *, int);

extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);

extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);

extern void blk_queue_unplugged(struct request_queue *, unplugged_fn *);

extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);

extern void blk_queue_flush(struct request_queue *q, unsigned int flush);

extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
@@ -862,14 +865,14 @@ struct blk_plug { 


extern void blk_start_plug(struct blk_plug *);

extern void blk_finish_plug(struct blk_plug *);

extern void __blk_flush_plug(struct task_struct *, struct blk_plug *);

extern void blk_flush_plug_list(struct blk_plug *, bool);



static inline void blk_flush_plug(struct task_struct *tsk)

{

	struct blk_plug *plug = tsk->plug;



	if (unlikely(plug))

		__blk_flush_plug(tsk, plug);

	if (plug)

		blk_flush_plug_list(plug, true);

}



static inline bool blk_needs_flush_plug(struct task_struct *tsk)

include/trace/events/block.h

+6 −19
Original line number Diff line number Diff line
@@ -401,9 +401,9 @@ TRACE_EVENT(block_plug, 


DECLARE_EVENT_CLASS(block_unplug,



	TP_PROTO(struct request_queue *q),

	TP_PROTO(struct request_queue *q, unsigned int depth),



	TP_ARGS(q),

	TP_ARGS(q, depth),



	TP_STRUCT__entry(

		__field( int,		nr_rq			)
@@ -411,39 +411,26 @@ DECLARE_EVENT_CLASS(block_unplug, 
	),



	TP_fast_assign(

		__entry->nr_rq	= q->rq.count[READ] + q->rq.count[WRITE];

		__entry->nr_rq = depth;

		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);

	),



	TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)

);



/**

 * block_unplug_timer - timed release of operations requests in queue to device driver

 * @q: request queue to unplug

 *

 * Unplug the request queue @q because a timer expired and allow block

 * operation requests to be sent to the device driver.

 */

DEFINE_EVENT(block_unplug, block_unplug_timer,



	TP_PROTO(struct request_queue *q),



	TP_ARGS(q)

);



/**

 * block_unplug_io - release of operations requests in request queue

 * @q: request queue to unplug

 * @depth: number of requests just added to the queue

 *

 * Unplug request queue @q because device driver is scheduled to work

 * on elements in the request queue.

 */

DEFINE_EVENT(block_unplug, block_unplug_io,



	TP_PROTO(struct request_queue *q),

	TP_PROTO(struct request_queue *q, unsigned int depth),



	TP_ARGS(q)

	TP_ARGS(q, depth)

);



/**

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