drivers/block/zram/zram_drv.c: fix error return codes not being returned in writeback...

Currently when an error code -EIO or -ENOSPC in the for-loop of
writeback_store the error code is being overwritten by a ret = len
assignment at the end of the function and the error codes are being
lost.  Fix this by assigning ret = len at the start of the function and
remove the assignment from the end, hence allowing ret to be preserved
when error codes are assigned to it.

Addresses Coverity ("Unused value")

Link: http://lkml.kernel.org/r/20191128122958.178290-1-colin.king@canonical.com
Fixes: 5a7c53a008fb ("zram: support idle/huge page writeback")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 71d594609b78ed49fc3ea9db464dd2eb6243fd78..1bdb5793842bd94a0b1f0e61fbc0f17bd2565779 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -629,7 +629,7 @@ static ssize_t writeback_store(struct device *dev,
        struct bio bio;
        struct bio_vec bio_vec;
        struct page *page;
-       ssize_t ret;
+       ssize_t ret = len;
        int mode;
        unsigned long blk_idx = 0;
 
@@ -765,7 +765,6 @@ next:
 
        if (blk_idx)
                free_block_bdev(zram, blk_idx);
-       ret = len;
        __free_page(page);
 release_init_lock:
        up_read(&zram->init_lock);