block: make sure discard bio is aligned with logical block size

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>

3 files changed, 13 insertions, 3 deletions

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 76f867ea9a9b..d56fd159d2e8 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -57,8 +57,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 
                 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;
 
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 208658a901c6..e7696c47489a 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -90,7 +90,8 @@ static struct bio *blk_bio_discard_split(struct request_queue *q,
         /* 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)) {
diff --git a/block/blk.h b/block/blk.h
index c85e53f21cdd..0089fefdf771 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -396,6 +396,16 @@ static inline unsigned long blk_rq_deadline(struct request *rq)
 }
 
 /*
+ * 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);