[PATCH 3.16 203/366] block: Fix transfer when chunk sectors exceeds max

[Ben Hutchings]

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Keith Busch <keith.busch@xxxxxxxxx>

commit 15bfd21fbc5d35834b9ea383dc458a1f0c9e3434 upstream.

A device may have boundary restrictions where the number of sectors
between boundaries exceeds its max transfer size. In this case, we need
to cap the max size to the smaller of the two limits.

Reported-by: Jitendra Bhivare <jitendra.bhivare@xxxxxxxxxxxx>
Tested-by: Jitendra Bhivare <jitendra.bhivare@xxxxxxxxxxxx>
Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 include/linux/blkdev.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -929,8 +929,8 @@ static inline unsigned int blk_max_size_
 	if (!q->limits.chunk_sectors)
 		return q->limits.max_sectors;
 
-	return q->limits.chunk_sectors -
-			(offset & (q->limits.chunk_sectors - 1));
+	return min(q->limits.max_sectors, (unsigned int)(q->limits.chunk_sectors -
+			(offset & (q->limits.chunk_sectors - 1))));
 }
 
 static inline unsigned int blk_rq_get_max_sectors(struct request *rq)