path: root/include/linux
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authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>2015-02-12 15:00:36 -0800
committerAlex Shi <alex.shi@linaro.org>2015-05-11 21:38:22 +0800
commit043787104c5b1386a96c317f2e82ecff257dd9c5 (patch)
treefa67236a309b7e0f92849211e6c9d2a0bc1687cf /include/linux
parent837e91c8966924792bf5ba5ef9a62eaa55489ff7 (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>
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