Commit f6ff53d3 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Jens Axboe
Browse files

block: reorganize rounding of max_discard_sectors 



Mostly a preparation for the next patch.

In principle this fixes an infinite loop if max_discard_sectors < granularity,
but that really shouldn't happen.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Tested-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1a9b4993

block/blk-lib.c

+5 −4
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, 
	struct request_queue *q = bdev_get_queue(bdev);

	int type = REQ_WRITE | REQ_DISCARD;

	unsigned int max_discard_sectors;

	unsigned int granularity;

	struct bio_batch bb;

	struct bio *bio;

	int ret = 0;
@@ -54,18 +55,18 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, 
	if (!blk_queue_discard(q))

		return -EOPNOTSUPP;



	/* Zero-sector (unknown) and one-sector granularities are the same.  */

	granularity = max(q->limits.discard_granularity >> 9, 1U);



	/*

	 * Ensure that max_discard_sectors is of the proper

	 * granularity

	 */

	max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);

	max_discard_sectors = round_down(max_discard_sectors, granularity);

	if (unlikely(!max_discard_sectors)) {

		/* Avoid infinite loop below. Being cautious never hurts. */

		return -EOPNOTSUPP;

	} else if (q->limits.discard_granularity) {

		unsigned int disc_sects = q->limits.discard_granularity >> 9;



		max_discard_sectors &= ~(disc_sects - 1);

	}



	if (flags & BLKDEV_DISCARD_SECURE) {