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authorMartin K. Petersen <martin.petersen@oracle.com>2010-01-11 03:21:48 -0500
committerJens Axboe <jens.axboe@oracle.com>2010-01-11 14:29:19 +0100
commitdd3d145d49c5816b79acc6761ebbd842bc50b0ee (patch)
tree107bdb2f46c6aa6bc482909d7ebdbb1da40b7b4f
parentfe0b393f2c0a0d23a9bc9ed7dc51a1ee511098bd (diff)
block: Fix discard alignment calculation and printing
Discard alignment reporting for partitions was incorrect. Update to match the algorithm used elsewhere. The alignment can be negative (misaligned). Fix format string accordingly. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
-rw-r--r--block/genhd.c2
-rw-r--r--include/linux/blkdev.h7
2 files changed, 6 insertions, 3 deletions
diff --git a/block/genhd.c b/block/genhd.c
index b11a4ad7d57..d13ba76a169 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -867,7 +867,7 @@ static ssize_t disk_discard_alignment_show(struct device *dev,
{
struct gendisk *disk = dev_to_disk(dev);
- return sprintf(buf, "%u\n", queue_discard_alignment(disk->queue));
+ return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
}
static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 9b98173a818..a41bcc8e140 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1148,8 +1148,11 @@ static inline int queue_discard_alignment(struct request_queue *q)
static inline int queue_sector_discard_alignment(struct request_queue *q,
sector_t sector)
{
- return ((sector << 9) - q->limits.discard_alignment)
- & (q->limits.discard_granularity - 1);
+ struct queue_limits *lim = &q->limits;
+ unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
+
+ return (lim->discard_granularity + lim->discard_alignment - alignment)
+ & (lim->discard_granularity - 1);
}
static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)