Patchwork [v2,8/9] dm thin: use generic helper to set max_discard_sectors

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Submitter NamJae Jeon
Date April 19, 2013, 4:42 p.m.
Message ID <>
Download mbox | patch
Permalink /patch/238079/
State New, archived
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NamJae Jeon - April 19, 2013, 4:42 p.m.
From: Namjae Jeon <>

It is better to use blk_queue_max_discard_sectors helper
function to set max_discard_sectors as it checks
max_discard_sectors upper limit UINT_MAX >> 9

similar issue was reported for mmc in below link

If multiple discard requests get merged, merged discard request's
size exceeds 4GB, there is possibility that merged discard request's
__data_len field may overflow.

This patch fixes this issue.

Signed-off-by: Namjae Jeon <>
Signed-off-by: Vivek Trivedi <>
 drivers/md/dm-thin.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)


diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 905b75f..237295a 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2513,7 +2513,8 @@  static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
 	struct pool *pool = pt->pool;
 	struct queue_limits *data_limits;
-	limits->max_discard_sectors = pool->sectors_per_block;
+	blk_queue_max_discard_sectors(bdev_get_queue(pt->data_dev->bdev),
+					pool->sectors_per_block);
 	 * discard_granularity is just a hint, and not enforced.