diff options
| -rw-r--r-- | include/linux/refcount.h | 4 | ||||
| -rw-r--r-- | lib/refcount.c | 28 |
2 files changed, 31 insertions, 1 deletions
diff --git a/include/linux/refcount.h b/include/linux/refcount.h index 4193c41e383a..a685da2c4522 100644 --- a/include/linux/refcount.h +++ b/include/linux/refcount.h @@ -98,5 +98,7 @@ extern __must_check bool refcount_dec_if_one(refcount_t *r); extern __must_check bool refcount_dec_not_one(refcount_t *r); extern __must_check bool refcount_dec_and_mutex_lock(refcount_t *r, struct mutex *lock); extern __must_check bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock); - +extern __must_check bool refcount_dec_and_lock_irqsave(refcount_t *r, + spinlock_t *lock, + unsigned long *flags); #endif /* _LINUX_REFCOUNT_H */ diff --git a/lib/refcount.c b/lib/refcount.c index 0eb48353abe3..d3b81cefce91 100644 --- a/lib/refcount.c +++ b/lib/refcount.c @@ -350,3 +350,31 @@ bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock) } EXPORT_SYMBOL(refcount_dec_and_lock); +/** + * refcount_dec_and_lock_irqsave - return holding spinlock with disabled + * interrupts if able to decrement refcount to 0 + * @r: the refcount + * @lock: the spinlock to be locked + * @flags: saved IRQ-flags if the is acquired + * + * Same as refcount_dec_and_lock() above except that the spinlock is acquired + * with disabled interupts. + * + * Return: true and hold spinlock if able to decrement refcount to 0, false + * otherwise + */ +bool refcount_dec_and_lock_irqsave(refcount_t *r, spinlock_t *lock, + unsigned long *flags) +{ + if (refcount_dec_not_one(r)) + return false; + + spin_lock_irqsave(lock, *flags); + if (!refcount_dec_and_test(r)) { + spin_unlock_irqrestore(lock, *flags); + return false; + } + + return true; +} +EXPORT_SYMBOL(refcount_dec_and_lock_irqsave); |