Commit f2d03d89 authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Jens Axboe
Browse files

lru_cache: use atomic operations when accessing lc->flags, always 



Or, depending on the way locking is implemented at the call sites,
some updates could be lost (has not been observed).

Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: default avatarChristoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://lore.kernel.org/r/20221122134301.69258-2-christoph.boehmwalder@linbit.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d4b2e0d4

lib/lru_cache.c

+2 −2
Original line number Diff line number Diff line
@@ -364,7 +364,7 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, unsig 
	struct lc_element *e;



	PARANOIA_ENTRY();

	if (lc->flags & LC_STARVING) {

	if (test_bit(__LC_STARVING, &lc->flags)) {

		++lc->starving;

		RETURN(NULL);

	}
@@ -417,7 +417,7 @@ static struct lc_element *__lc_get(struct lru_cache *lc, unsigned int enr, unsig 
	 * the LRU element, we have to wait ...

	 */

	if (!lc_unused_element_available(lc)) {

		__set_bit(__LC_STARVING, &lc->flags);

		set_bit(__LC_STARVING, &lc->flags);

		RETURN(NULL);

	}