diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2021-10-21 14:30:51 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-10-21 08:37:26 -0600 |
| commit | 3b13c168186c115501ee7d194460ba2f8c825155 (patch) | |
| tree | 1ab6f6dda7d1b04e41c3bb4adbbc0338ff350693 /include/linux/percpu-refcount.h | |
| parent | 6549a874fb65e7ad4885d066ec314191cc137b52 (diff) | |
percpu_ref: percpu_ref_tryget_live() version holding RCU
Add percpu_ref_tryget_live_rcu(), which is a version of
percpu_ref_tryget_live() but the user is responsible for enclosing it in
a RCU read lock section.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Acked-by: Dennis Zhou <dennis@kernel.org>
Link: https://lore.kernel.org/r/3066500d7a6eb3e03f10adf98b87fdb3b1c49db8.1634822969.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/percpu-refcount.h')
| -rw-r--r-- | include/linux/percpu-refcount.h | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index ae16a9856305..b31d3f3312ce 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -267,6 +267,28 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref) } /** + * percpu_ref_tryget_live_rcu - same as percpu_ref_tryget_live() but the + * caller is responsible for taking RCU. + * + * This function is safe to call as long as @ref is between init and exit. + */ +static inline bool percpu_ref_tryget_live_rcu(struct percpu_ref *ref) +{ + unsigned long __percpu *percpu_count; + bool ret = false; + + WARN_ON_ONCE(!rcu_read_lock_held()); + + if (likely(__ref_is_percpu(ref, &percpu_count))) { + this_cpu_inc(*percpu_count); + ret = true; + } else if (!(ref->percpu_count_ptr & __PERCPU_REF_DEAD)) { + ret = atomic_long_inc_not_zero(&ref->data->count); + } + return ret; +} + +/** * percpu_ref_tryget_live - try to increment a live percpu refcount * @ref: percpu_ref to try-get * @@ -283,20 +305,11 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref) */ static inline bool percpu_ref_tryget_live(struct percpu_ref *ref) { - unsigned long __percpu *percpu_count; bool ret = false; rcu_read_lock(); - - if (__ref_is_percpu(ref, &percpu_count)) { - this_cpu_inc(*percpu_count); - ret = true; - } else if (!(ref->percpu_count_ptr & __PERCPU_REF_DEAD)) { - ret = atomic_long_inc_not_zero(&ref->data->count); - } - + ret = percpu_ref_tryget_live_rcu(ref); rcu_read_unlock(); - return ret; } |