zram: fix return value on writeback_store

writeback_store's return value is overwritten by submit_bio_wait's return
value.  Thus, writeback_store will return zero since there was no IO
error.  In the end, write syscall from userspace will see the zero as
return value, which could make the process stall to keep trying the write
until it will succeed.

Link: https://lkml.kernel.org/r/20210312173949.2197662-1-minchan@kernel.org
Fixes: 3b82a051c101("drivers/block/zram/zram_drv.c: fix error return codes not being returned in writeback_store")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: John Dias <joaodias@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Minchan Kim 2021-03-12 21:08:38 -08:00 committed by Linus Torvalds
parent e1baddf847
commit 57e0076e65

View File

@ -627,7 +627,7 @@ static ssize_t writeback_store(struct device *dev,
struct bio_vec bio_vec;
struct page *page;
ssize_t ret = len;
int mode;
int mode, err;
unsigned long blk_idx = 0;
if (sysfs_streq(buf, "idle"))
@ -728,12 +728,17 @@ static ssize_t writeback_store(struct device *dev,
* XXX: A single page IO would be inefficient for write
* but it would be not bad as starter.
*/
ret = submit_bio_wait(&bio);
if (ret) {
err = submit_bio_wait(&bio);
if (err) {
zram_slot_lock(zram, index);
zram_clear_flag(zram, index, ZRAM_UNDER_WB);
zram_clear_flag(zram, index, ZRAM_IDLE);
zram_slot_unlock(zram, index);
/*
* Return last IO error unless every IO were
* not suceeded.
*/
ret = err;
continue;
}