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authorChristoph Hellwig <hch@lst.de>2022-04-15 06:52:53 +0200
committerJens Axboe <axboe@kernel.dk>2022-04-17 19:49:59 -0600
commite3cc28ea28b5f8794db2aed24f8a0282ad2e85a2 (patch)
tree725631a2f3bff8b70df2d269576529e5c37c91de /block
parent5c4b4a5c6f11c869a57c6bd977143430bc9dc43d (diff)
block: refactor discard bio size limiting
Move all the logic to limit the discard bio size into a common helper so that it is better documented. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Coly Li <colyli@suse.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20220415045258.199825-23-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-lib.c59
-rw-r--r--block/blk.h14
2 files changed, 29 insertions, 44 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 237d60d8b585..2ae32a722851 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -10,6 +10,32 @@
#include "blk.h"
+static sector_t bio_discard_limit(struct block_device *bdev, sector_t sector)
+{
+ unsigned int discard_granularity =
+ bdev_get_queue(bdev)->limits.discard_granularity;
+ sector_t granularity_aligned_sector;
+
+ if (bdev_is_partition(bdev))
+ sector += bdev->bd_start_sect;
+
+ granularity_aligned_sector =
+ round_up(sector, discard_granularity >> SECTOR_SHIFT);
+
+ /*
+ * Make sure subsequent bios start aligned to the discard granularity if
+ * it needs to be split.
+ */
+ if (granularity_aligned_sector != sector)
+ return granularity_aligned_sector - sector;
+
+ /*
+ * Align the bio size to the discard granularity to make splitting the bio
+ * at discard granularity boundaries easier in the driver if needed.
+ */
+ return round_down(UINT_MAX, discard_granularity) >> SECTOR_SHIFT;
+}
+
int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, int flags,
struct bio **biop)
@@ -17,7 +43,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
struct request_queue *q = bdev_get_queue(bdev);
struct bio *bio = *biop;
unsigned int op;
- sector_t bs_mask, part_offset = 0;
+ sector_t bs_mask;
if (bdev_read_only(bdev))
return -EPERM;
@@ -48,36 +74,9 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
if (!nr_sects)
return -EINVAL;
- /* In case the discard request is in a partition */
- if (bdev_is_partition(bdev))
- part_offset = bdev->bd_start_sect;
-
while (nr_sects) {
- sector_t granularity_aligned_lba, req_sects;
- sector_t sector_mapped = sector + part_offset;
-
- granularity_aligned_lba = round_up(sector_mapped,
- q->limits.discard_granularity >> SECTOR_SHIFT);
-
- /*
- * Check whether the discard bio starts at a discard_granularity
- * aligned LBA,
- * - If no: set (granularity_aligned_lba - sector_mapped) to
- * bi_size of the first split bio, then the second bio will
- * start at a discard_granularity aligned LBA on the device.
- * - If yes: use bio_aligned_discard_max_sectors() as the max
- * possible bi_size of the first split bio. Then when this bio
- * is split in device drive, the split ones are very probably
- * to be aligned to discard_granularity of the device's queue.
- */
- if (granularity_aligned_lba == sector_mapped)
- req_sects = min_t(sector_t, nr_sects,
- bio_aligned_discard_max_sectors(q));
- else
- req_sects = min_t(sector_t, nr_sects,
- granularity_aligned_lba - sector_mapped);
-
- WARN_ON_ONCE((req_sects << 9) > UINT_MAX);
+ sector_t req_sects =
+ min(nr_sects, bio_discard_limit(bdev, sector));
bio = blk_next_bio(bio, bdev, 0, op, gfp_mask);
bio->bi_iter.bi_sector = sector;
diff --git a/block/blk.h b/block/blk.h
index 4ea5167dc339..434017701403 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -347,20 +347,6 @@ static inline unsigned int bio_allowed_max_sectors(struct request_queue *q)
}
/*
- * The max bio size which is aligned to q->limits.discard_granularity. This
- * is a hint to split large discard bio in generic block layer, then if device
- * driver needs to split the discard bio into smaller ones, their bi_size can
- * be very probably and easily aligned to discard_granularity of the device's
- * queue.
- */
-static inline unsigned int bio_aligned_discard_max_sectors(
- struct request_queue *q)
-{
- return round_down(UINT_MAX, q->limits.discard_granularity) >>
- SECTOR_SHIFT;
-}
-
-/*
* Internal io_context interface
*/
struct io_cq *ioc_find_get_icq(struct request_queue *q);