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

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
...@@ -44,6 +44,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, ...@@ -44,6 +44,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
struct request_queue *q = bdev_get_queue(bdev); struct request_queue *q = bdev_get_queue(bdev);
int type = REQ_WRITE | REQ_DISCARD; int type = REQ_WRITE | REQ_DISCARD;
unsigned int max_discard_sectors; unsigned int max_discard_sectors;
unsigned int granularity;
struct bio_batch bb; struct bio_batch bb;
struct bio *bio; struct bio *bio;
int ret = 0; int ret = 0;
...@@ -54,18 +55,18 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, ...@@ -54,18 +55,18 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
if (!blk_queue_discard(q)) if (!blk_queue_discard(q))
return -EOPNOTSUPP; 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 * Ensure that max_discard_sectors is of the proper
* granularity * granularity
*/ */
max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); 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)) { if (unlikely(!max_discard_sectors)) {
/* Avoid infinite loop below. Being cautious never hurts. */ /* Avoid infinite loop below. Being cautious never hurts. */
return -EOPNOTSUPP; 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) { if (flags & BLKDEV_DISCARD_SECURE) {
......
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