[PATCH 4.19 019/361] block: make sure discard bio is aligned with logical block size

Greg Kroah-Hartman
2018-11-12T00:19:57Z

From: Ming Lei <ming.lei@redhat.com>

commit 1adfc5e4136f5967d591c399aff95b3b035f16b7 upstream.

Obviously the created discard bio has to be aligned with logical block size.

This patch introduces the helper of bio_allowed_max_sectors() for
this purpose.

Cc: stable@vger.kernel.org
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Xiao Ni <xni@redhat.com>
Cc: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Fixes: 744889b7cbb56a6 ("block: don't deal with discard limit in blkdev_issue_discard()")
Fixes: a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks")
Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
Tested-by: Rui Salvaterra <rsalvaterra@gmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
block/blk-lib.c | 3 +--
block/blk-merge.c | 3 ++-
block/blk.h | 10 ++++++++++
3 files changed, 13 insertions(+), 3 deletions(-)

--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -58,8 +58,7 @@ int __blkdev_issue_discard(struct block_

if (!req_sects)
goto fail;
- if (req_sects > UINT_MAX >> 9)
- req_sects = UINT_MAX >> 9;
+ req_sects = min(req_sects, bio_allowed_max_sectors(q));

end_sect = sector + req_sects;

--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -27,7 +27,8 @@ static struct bio *blk_bio_discard_split
/* Zero-sector (unknown) and one-sector granularities are the same. */
granularity = max(q->limits.discard_granularity >> 9, 1U);

- max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
+ max_discard_sectors = min(q->limits.max_discard_sectors,
+ bio_allowed_max_sectors(q));
max_discard_sectors -= max_discard_sectors % granularity;

if (unlikely(!max_discard_sectors)) {
--- a/block/blk.h
+++ b/block/blk.h
@@ -329,6 +329,16 @@ static inline unsigned long blk_rq_deadl
}

/*
+ * The max size one bio can handle is UINT_MAX becasue bvec_iter.bi_size
+ * is defined as 'unsigned int', meantime it has to aligned to with logical
+ * block size which is the minimum accepted unit by hardware.
+ */
+static inline unsigned int bio_allowed_max_sectors(struct request_queue *q)
+{
+ return round_down(UINT_MAX, queue_logical_block_size(q)) >> 9;
+}
+
+/*
* Internal io_context interface
*/
void get_io_context(struct io_context *ioc);