Commit 65f666c6 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

lib/sbitmap: define swap_lock as raw_spinlock_t 



When called from sbitmap_queue_get(), sbitmap_deferred_clear() may be run
with preempt disabled. In RT kernel, spin_lock() can sleep, then warning
of "BUG: sleeping function called from invalid context" can be triggered.

Fix it by replacing it with raw_spin_lock.

Cc: Yang Yang <yang.yang@vivo.com>
Fixes: 72d04bdc ("sbitmap: fix io hung due to race on sbitmap_word::cleared")
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarYang Yang <yang.yang@vivo.com>
Link: https://lore.kernel.org/r/20240919021709.511329-1-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9ba5dcc7

include/linux/sbitmap.h

+1 −1
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ struct sbitmap_word { 
	/**

	 * @swap_lock: serializes simultaneous updates of ->word and ->cleared

	 */

	spinlock_t swap_lock;

	raw_spinlock_t swap_lock;

} ____cacheline_aligned_in_smp;



/**

lib/sbitmap.c

+2 −2
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ static inline bool sbitmap_deferred_clear(struct sbitmap_word *map, 
{

	unsigned long mask, word_mask;



	guard(spinlock_irqsave)(&map->swap_lock);

	guard(raw_spinlock_irqsave)(&map->swap_lock);



	if (!map->cleared) {

		if (depth == 0)
@@ -136,7 +136,7 @@ int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, 
	}



	for (i = 0; i < sb->map_nr; i++)

		spin_lock_init(&sb->map[i].swap_lock);

		raw_spin_lock_init(&sb->map[i].swap_lock);



	return 0;

}