diff options
author | Sergey Senozhatsky <sergey.senozhatsky@gmail.com> | 2015-02-12 15:00:36 -0800 |
---|---|---|
committer | Alex Shi <alex.shi@linaro.org> | 2015-05-11 21:38:22 +0800 |
commit | 043787104c5b1386a96c317f2e82ecff257dd9c5 (patch) | |
tree | fa67236a309b7e0f92849211e6c9d2a0bc1687cf /lib/bcd.c | |
parent | 837e91c8966924792bf5ba5ef9a62eaa55489ff7 (diff) |
zram: fix umount-reset_store-mount race conditionv3.10/topic/zram
Ganesh Mahendran was the first one who proposed to use bdev->bd_mutex to
avoid ->bd_holders race condition:
CPU0 CPU1
umount /* zram->init_done is true */
reset_store()
bdev->bd_holders == 0 mount
... zram_make_request()
zram_reset_device()
However, his solution required some considerable amount of code movement,
which we can avoid.
Apart from using bdev->bd_mutex in reset_store(), this patch also
simplifies zram_reset_device().
zram_reset_device() has a bool parameter reset_capacity which tells it
whether disk capacity and itself disk should be reset. There are two
zram_reset_device() callers:
-- zram_exit() passes reset_capacity=false
-- reset_store() passes reset_capacity=true
So we can move reset_capacity-sensitive work out of zram_reset_device()
and perform it unconditionally in reset_store(). This also lets us drop
reset_capacity parameter from zram_reset_device() and pass zram pointer
only.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit ba6b17d68c8e3aa8d55d0474299cb931965c5ea5)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
Diffstat (limited to 'lib/bcd.c')
0 files changed, 0 insertions, 0 deletions