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block: assert that we're not holding open_mutex over blk_report_disk_dead

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blk_report_disk_dead() has the following major callers:

(1) del_gendisk()
(2) blk_mark_disk_dead()

Since del_gendisk() acquires disk->open_mutex it's clear that all
callers are assumed to be called without disk->open_mutex held.
In turn, blk_report_disk_dead() is called without disk->open_mutex held
in del_gendisk().

All callers of blk_mark_disk_dead() call it without disk->open_mutex as
well.

Ensure that it is clear that blk_report_disk_dead() is called without
disk->open_mutex on purpose by asserting it and a comment in the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231017184823.1383356-5-hch@lst.de
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2023-10-17 20:48:22 +02:00
parent 6e57236ed6
commit f61033390b
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1 changed files with 7 additions and 0 deletions
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7
block/genhd.c
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@ -559,6 +559,13 @@ static void blk_report_disk_dead(struct gendisk *disk, bool surprise)
struct block_device *bdev; struct block_device *bdev;
unsigned long idx; unsigned long idx;
/*
* On surprise disk removal, bdev_mark_dead() may call into file
* systems below. Make it clear that we're expecting to not hold
* disk->open_mutex.
*/
lockdep_assert_not_held(&disk->open_mutex);
rcu_read_lock(); rcu_read_lock();
xa_for_each(&disk->part_tbl, idx, bdev) { xa_for_each(&disk->part_tbl, idx, bdev) {
if (!kobject_get_unless_zero(&bdev->bd_device.kobj)) if (!kobject_get_unless_zero(&bdev->bd_device.kobj))