commit 0d8359620d ("zram: support page writeback") introduced two
problems. It overwrites writeback_store's return value as kstrtol's
return value, which makes return value zero so user could see zero as
return value of write syscall even though it wrote data successfully.
It also breaks index value in the loop in that it doesn't increase the
index any longer. It means it can write only first starting block index
so user couldn't write all idle pages in the zram so lose memory saving
chance.
This patch fixes those issues.
Link: https://lkml.kernel.org/r/20210312173949.2197662-2-minchan@kernel.org
Fixes: 0d8359620d9b("zram: support page writeback")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: Amos Bianchi <amosbianchi@google.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.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>
(cherry picked from commit 2766f18216)
Bug: 182850185
Signed-off-by: Amos Bianchi <amosbianchi@google.com>
Change-Id: I9836b6350727dc4fffc1cc939647235781f0a4ee
e4636b47ef