diff options
| -rw-r--r-- | include/linux/wait_bit.h | 17 | ||||
| -rw-r--r-- | mm/backing-dev.c | 2 |
2 files changed, 18 insertions, 1 deletions
diff --git a/include/linux/wait_bit.h b/include/linux/wait_bit.h index 9318b2166439..2b0072fa5e92 100644 --- a/include/linux/wait_bit.h +++ b/include/linux/wait_bit.h @@ -305,4 +305,21 @@ do { \ __ret; \ }) +/** + * clear_and_wake_up_bit - clear a bit and wake up anyone waiting on that bit + * + * @bit: the bit of the word being waited on + * @word: the word being waited on, a kernel virtual address + * + * You can use this helper if bitflags are manipulated atomically rather than + * non-atomically under a lock. + */ +static inline void clear_and_wake_up_bit(int bit, void *word) +{ + clear_bit_unlock(bit, word); + /* See wake_up_bit() for which memory barrier you need to use. */ + smp_mb__after_atomic(); + wake_up_bit(word, bit); +} + #endif /* _LINUX_WAIT_BIT_H */ diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 023190c69dce..fa5e6d7406d1 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -383,7 +383,7 @@ static void wb_shutdown(struct bdi_writeback *wb) * the barrier provided by test_and_clear_bit() above. */ smp_wmb(); - clear_bit(WB_shutting_down, &wb->state); + clear_and_wake_up_bit(WB_shutting_down, &wb->state); } static void wb_exit(struct bdi_writeback *wb) |