diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/percpu-refcount.c | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c index f3ff793691ac..c69938e4b0d5 100644 --- a/lib/percpu-refcount.c +++ b/lib/percpu-refcount.c @@ -33,6 +33,7 @@ #define PERCPU_COUNT_BIAS (1LU << (BITS_PER_LONG - 1)) +static DEFINE_SPINLOCK(percpu_ref_switch_lock); static DECLARE_WAIT_QUEUE_HEAD(percpu_ref_switch_waitq); static unsigned long __percpu *percpu_count_ptr(struct percpu_ref *ref) @@ -208,15 +209,15 @@ static void __percpu_ref_switch_to_percpu(struct percpu_ref *ref) static void __percpu_ref_switch_mode(struct percpu_ref *ref, percpu_ref_func_t *confirm_switch) { + lockdep_assert_held(&percpu_ref_switch_lock); + /* * If the previous ATOMIC switching hasn't finished yet, wait for * its completion. If the caller ensures that ATOMIC switching * isn't in progress, this function can be called from any context. - * Do an extra confirm_switch test to circumvent the unconditional - * might_sleep() in wait_event(). */ - if (ref->confirm_switch) - wait_event(percpu_ref_switch_waitq, !ref->confirm_switch); + wait_event_lock_irq(percpu_ref_switch_waitq, !ref->confirm_switch, + percpu_ref_switch_lock); if (ref->force_atomic || (ref->percpu_count_ptr & __PERCPU_REF_DEAD)) __percpu_ref_switch_to_atomic(ref, confirm_switch); @@ -247,8 +248,14 @@ static void __percpu_ref_switch_mode(struct percpu_ref *ref, void percpu_ref_switch_to_atomic(struct percpu_ref *ref, percpu_ref_func_t *confirm_switch) { + unsigned long flags; + + spin_lock_irqsave(&percpu_ref_switch_lock, flags); + ref->force_atomic = true; __percpu_ref_switch_mode(ref, confirm_switch); + + spin_unlock_irqrestore(&percpu_ref_switch_lock, flags); } /** @@ -271,8 +278,14 @@ void percpu_ref_switch_to_atomic(struct percpu_ref *ref, */ void percpu_ref_switch_to_percpu(struct percpu_ref *ref) { + unsigned long flags; + + spin_lock_irqsave(&percpu_ref_switch_lock, flags); + ref->force_atomic = false; __percpu_ref_switch_mode(ref, NULL); + + spin_unlock_irqrestore(&percpu_ref_switch_lock, flags); } /** @@ -293,12 +306,18 @@ void percpu_ref_switch_to_percpu(struct percpu_ref *ref) void percpu_ref_kill_and_confirm(struct percpu_ref *ref, percpu_ref_func_t *confirm_kill) { + unsigned long flags; + + spin_lock_irqsave(&percpu_ref_switch_lock, flags); + WARN_ONCE(ref->percpu_count_ptr & __PERCPU_REF_DEAD, "%s called more than once on %pf!", __func__, ref->release); ref->percpu_count_ptr |= __PERCPU_REF_DEAD; __percpu_ref_switch_mode(ref, confirm_kill); percpu_ref_put(ref); + + spin_unlock_irqrestore(&percpu_ref_switch_lock, flags); } EXPORT_SYMBOL_GPL(percpu_ref_kill_and_confirm); @@ -315,10 +334,16 @@ EXPORT_SYMBOL_GPL(percpu_ref_kill_and_confirm); */ void percpu_ref_reinit(struct percpu_ref *ref) { + unsigned long flags; + + spin_lock_irqsave(&percpu_ref_switch_lock, flags); + WARN_ON_ONCE(!percpu_ref_is_zero(ref)); ref->percpu_count_ptr &= ~__PERCPU_REF_DEAD; percpu_ref_get(ref); __percpu_ref_switch_mode(ref, NULL); + + spin_unlock_irqrestore(&percpu_ref_switch_lock, flags); } EXPORT_SYMBOL_GPL(percpu_ref_reinit); |