linux/drivers/block/loop.c, branch v5.14

loop: reintroduce global lock for safe loop_validate_file() traversal

2021-07-23T16:18:25Z

Commit 6cc8e7430801fa23 ("loop: scale loop device by introducing per device lock") re-opened a race window for NULL pointer dereference at loop_validate_file() where commit 310ca162d779efee ("block/loop: Use global lock for ioctl() operation.") has closed. Although we need to guarantee that other loop devices will not change during traversal, we can't take remote "struct loop_device"->lo_mutex inside loop_validate_file() in order to avoid AB-BA deadlock. Therefore, introduce a global lock dedicated for loop_validate_file() which is conditionally taken before local "struct loop_device"->lo_mutex is taken. Signed-off-by: Tetsuo Handa Fixes: 6cc8e7430801fa23 ("loop: scale loop device by introducing per device lock") Signed-off-by: Jens Axboe

loop: remove unused variable in loop_set_status()

2021-07-02T15:28:42Z

Commit 0384264ea8a39bd9 ("block: pass a gendisk to bdev_disk_changed") changed to pass lo->lo_disk instead of lo->lo_device. Fixes: 0384264ea8a3 ("block: pass a gendisk to bdev_disk_changed") Signed-off-by: Tetsuo Handa Link: https://lore.kernel.org/r/20210702152714.7978-1-penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Jens Axboe

loop: rewrite loop_exit using idr_for_each_entry

2021-06-30T21:34:13Z

Use idr_for_each_entry to simplify removing all devices. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20210623145908.92973-10-hch@lst.de Signed-off-by: Jens Axboe

loop: split loop_lookup

2021-06-30T21:34:13Z

loop_lookup has two callers - one wants to do the a find by index and the other wants any unbound loop device. Open code the respective functionality in each caller. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210623145908.92973-9-hch@lst.de Signed-off-by: Jens Axboe

loop: don't allow deleting an unspecified loop device

2021-06-30T21:34:13Z

Passing a negative index to loop_lookup while return any unbound device. Doing that for a delete does not make much sense, so add check to explicitly reject that case. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210623145908.92973-8-hch@lst.de Signed-off-by: Jens Axboe

loop: move loop_ctl_mutex locking into loop_add

2021-06-30T21:34:13Z

Move acquiring and releasing loop_ctl_mutex from the callers into loop_add. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20210623145908.92973-7-hch@lst.de Signed-off-by: Jens Axboe

loop: split loop_control_ioctl

2021-06-30T21:34:13Z

Split loop_control_ioctl into a helper for each command. This keeps the code nicely separated for the upcoming locking changes. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20210623145908.92973-6-hch@lst.de Signed-off-by: Jens Axboe

loop: don't call loop_lookup before adding a loop device

2021-06-30T21:34:13Z

loop_add returns the right error if the slot wasn't available. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210623145908.92973-5-hch@lst.de Signed-off-by: Jens Axboe

loop: remove the l argument to loop_add

2021-06-30T21:34:13Z

None of the callers cares about the allocated struct loop_device. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20210623145908.92973-4-hch@lst.de Signed-off-by: Jens Axboe

loop: reduce loop_ctl_mutex coverage in loop_exit

2021-06-30T21:34:13Z

loop_ctl_mutex is only needed to iterate the IDR for removing the loop devices, so reduce the coverage. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20210623145908.92973-3-hch@lst.de Signed-off-by: Jens Axboe