[PATCH] zram: correct offset usage in zram_bio_discard

[Weijie Yang]

we want to skip the logical block which is partially covered by
the discard bio, so check the remaining size and subtract it if
there is a need to goto the next logical block.

This patch corrects the offset usage in zram_bio_discard.

Signed-off-by: Weijie Yang <weijie.yang@xxxxxxxxxxx>
---
 drivers/block/zram/zram_drv.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9849b52..48eccb3 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -572,10 +572,10 @@ static void zram_bio_discard(struct zram *zram, u32 index,
 	 * skipping this logical block is appropriate here.
 	 */
 	if (offset) {
-		if (n < offset)
+		if (n <= (PAGE_SIZE - offset))
 			return;
 
-		n -= offset;
+		n -= (PAGE_SIZE - offset);
 		index++;
 	}
 
-- 
1.7.10.4


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