[PATCH 4/4] Limit max_discard_sectors to UINT_MAX>>9

From: Gwendal Grignou
Date: Tue Mar 25 2014 - 19:51:17 EST


max_discard_sectors can not be larger than UINT_MAX>>9,
otherwise, there is a risk that discard requests would be merged
into a request larger than 4GB.

Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
---
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 5073cbc..e74090c 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -416,7 +416,7 @@ 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;
+ new->rq->limits.max_discard_sectors = UINT_MAX >> 9;
}

gd->queue = new->rq;
--
1.9.1.423.g4596e3a

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