Commit e692cb66 authored by Martin K. Petersen's avatar Martin K. Petersen Committed by Jens Axboe
Browse files

block: Deprecate QUEUE_FLAG_CLUSTER and use queue_limits instead 



When stacking devices, a request_queue is not always available. This
forced us to have a no_cluster flag in the queue_limits that could be
used as a carrier until the request_queue had been set up for a
metadevice.

There were several problems with that approach. First of all it was up
to the stacking device to remember to set queue flag after stacking had
completed. Also, the queue flag and the queue limits had to be kept in
sync at all times. We got that wrong, which could lead to us issuing
commands that went beyond the max scatterlist limit set by the driver.

The proper fix is to avoid having two flags for tracking the same thing.
We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the
block layer merging functions. The queue_limit 'no_cluster' is turned
into 'cluster' to avoid double negatives and to ease stacking.
Clustering defaults to being enabled as before. The queue flag logic is
removed from the stacking function, and explicitly setting the cluster
flag is no longer necessary in DM and MD.

Reported-by: default avatarEd Lin <ed.lin@promise.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: default avatarMike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 04a6b516

block/blk-merge.c

+3 −3
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, 
		return 0;



	fbio = bio;

	cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);

	cluster = blk_queue_cluster(q);

	seg_size = 0;

	nr_phys_segs = 0;

	for_each_bio(bio) {
@@ -87,7 +87,7 @@ EXPORT_SYMBOL(blk_recount_segments); 
static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,

				   struct bio *nxt)

{

	if (!test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))

	if (!blk_queue_cluster(q))

		return 0;



	if (bio->bi_seg_back_size + nxt->bi_seg_front_size >
@@ -123,7 +123,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, 
	int nsegs, cluster;



	nsegs = 0;

	cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);

	cluster = blk_queue_cluster(q);



	/*

	 * for each bio in rq

block/blk-settings.c

+2 −23
Original line number Diff line number Diff line
@@ -126,7 +126,7 @@ void blk_set_default_limits(struct queue_limits *lim) 
	lim->alignment_offset = 0;

	lim->io_opt = 0;

	lim->misaligned = 0;

	lim->no_cluster = 0;

	lim->cluster = 1;

}

EXPORT_SYMBOL(blk_set_default_limits);
@@ -464,15 +464,6 @@ EXPORT_SYMBOL(blk_queue_io_opt); 
void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)

{

	blk_stack_limits(&t->limits, &b->limits, 0);



	if (!t->queue_lock)

		WARN_ON_ONCE(1);

	else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) {

		unsigned long flags;

		spin_lock_irqsave(t->queue_lock, flags);

		queue_flag_clear(QUEUE_FLAG_CLUSTER, t);

		spin_unlock_irqrestore(t->queue_lock, flags);

	}

}

EXPORT_SYMBOL(blk_queue_stack_limits);
@@ -545,7 +536,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, 
	t->io_min = max(t->io_min, b->io_min);

	t->io_opt = lcm(t->io_opt, b->io_opt);



	t->no_cluster |= b->no_cluster;

	t->cluster &= b->cluster;

	t->discard_zeroes_data &= b->discard_zeroes_data;



	/* Physical block size a multiple of the logical block size? */
@@ -641,7 +632,6 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, 
		       sector_t offset)

{

	struct request_queue *t = disk->queue;

	struct request_queue *b = bdev_get_queue(bdev);



	if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {

		char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
@@ -652,17 +642,6 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, 
		printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",

		       top, bottom);

	}



	if (!t->queue_lock)

		WARN_ON_ONCE(1);

	else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) {

		unsigned long flags;



		spin_lock_irqsave(t->queue_lock, flags);

		if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))

			queue_flag_clear(QUEUE_FLAG_CLUSTER, t);

		spin_unlock_irqrestore(t->queue_lock, flags);

	}

}

EXPORT_SYMBOL(disk_stack_limits);

block/blk-sysfs.c

+1 −1
Original line number Diff line number Diff line
@@ -119,7 +119,7 @@ static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char * 


static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)

{

	if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))

	if (blk_queue_cluster(q))

		return queue_var_show(queue_max_segment_size(q), (page));



	return queue_var_show(PAGE_CACHE_SIZE, (page));

drivers/md/dm-table.c

+0 −5
Original line number Diff line number Diff line
@@ -1131,11 +1131,6 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, 
	 */

	q->limits = *limits;



	if (limits->no_cluster)

		queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);

	else

		queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, q);



	if (!dm_table_supports_discards(t))

		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);

	else

drivers/md/md.c

+0 −3
Original line number Diff line number Diff line
@@ -4296,9 +4296,6 @@ static int md_alloc(dev_t dev, char *name) 
		goto abort;

	mddev->queue->queuedata = mddev;



	/* Can be unlocked because the queue is new: no concurrency */

	queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, mddev->queue);



	blk_queue_make_request(mddev->queue, md_make_request);



	disk = alloc_disk(1 << shift);

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