[PATCH 3/8] mtd: use generic helper to set max_discard_sectors

From: Namjae Jeon
Date: Sat Apr 13 2013 - 09:39:01 EST


From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>

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
https://lkml.org/lkml/2013/4/1/292

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 <namjae.jeon@xxxxxxxxxxx>
Signed-off-by: Vivek Trivedi <t.vivek@xxxxxxxxxxx>
---
drivers/mtd/mtd_blkdevs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 5ad39bb..cf35f99 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -417,7 +417,7 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)

if (tr->discard) {
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
- new->rq->limits.max_discard_sectors = UINT_MAX;
+ blk_queue_max_discard_sectors(new->rq, UINT_MAX >> 9);
}

gd->queue = new->rq;
--
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/