block: Fix incorrect reporting of partition alignment

commit 81744ee44ab2845c16ffd7d6f762f7b4a49a4750 upstream

queue_sector_alignment_offset returned the wrong value which caused
partitions to report an incorrect alignment_offset. Since offset
calculation is needed several places it has been split into a separate
helper function.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 221cecd86bd3bf031e583ac37139be43355fbfec..adf99c617cd3e54d7725a3e1d7c54cdddb30db4d 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1114,11 +1114,18 @@ static inline int queue_alignment_offset(struct request_queue *q)
        return q->limits.alignment_offset;
 }
 
+static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t offset)
+{
+       unsigned int granularity = max(lim->physical_block_size, lim->io_min);
+
+       offset &= granularity - 1;
+       return (granularity + lim->alignment_offset - offset) & (granularity - 1);
+}
+
 static inline int queue_sector_alignment_offset(struct request_queue *q,
                                                sector_t sector)
 {
-       return ((sector << 9) - q->limits.alignment_offset)
-               & (q->limits.io_min - 1);
+       return queue_limit_alignment_offset(&q->limits, sector << 9);
 }
 
 static inline int bdev_alignment_offset(struct block_device *bdev)