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ataflop: remove ataflop_probe_lock mutex
[ Upstream commit 4ddb85d ] Commit bf9c053 ("ataflop: use a separate gendisk for each media format") introduced ataflop_probe_lock mutex, but forgot to unlock the mutex when atari_floppy_init() (i.e. module loading) succeeded. This will result in double lock deadlock if ataflop_probe() is called. Also, unregister_blkdev() must not be called from atari_floppy_init() with ataflop_probe_lock held when atari_floppy_init() failed, for ataflop_probe() waits for ataflop_probe_lock with major_names_lock held (i.e. AB-BA deadlock). __register_blkdev() needs to be called last in order to avoid calling ataflop_probe() when atari_floppy_init() is about to fail, for memory for completing already-started ataflop_probe() safely will be released as soon as atari_floppy_init() released ataflop_probe_lock mutex. As with commit 8b52d8b ("loop: reorder loop_exit"), unregister_blkdev() needs to be called first in order to avoid calling ataflop_alloc_disk() from ataflop_probe() after del_gendisk() from atari_floppy_exit(). By relocating __register_blkdev() / unregister_blkdev() as explained above, we can remove ataflop_probe_lock mutex, for probe function and __exit function are serialized by major_names_lock mutex. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Fixes: bf9c053 ("ataflop: use a separate gendisk for each media format") Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Tested-by: Michael Schmitz <schmitzmic@gmail.com> Link: https://lore.kernel.org/r/20211103230437.1639990-11-mcgrof@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
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