From c2e25c107b74a9e2ac43fb93a077a7ec98e6a4a5 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sat, 28 Dec 2019 14:13:02 +0300 Subject: [PATCH] pcpu_ref: add percpu_ref_tryget_many() Add percpu_ref_tryget_many(), which works the same way as percpu_ref_tryget(), but grabs specified number of refs. Signed-off-by: Pavel Begunkov Acked-by: Tejun Heo Acked-by: Dennis Zhou Cc: Christoph Lameter Signed-off-by: Jens Axboe --- include/linux/percpu-refcount.h | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 390031e816dcd..22d9d183950dc 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -210,15 +210,17 @@ static inline void percpu_ref_get(struct percpu_ref *ref) } /** - * percpu_ref_tryget - try to increment a percpu refcount + * percpu_ref_tryget_many - try to increment a percpu refcount * @ref: percpu_ref to try-get + * @nr: number of references to get * - * Increment a percpu refcount unless its count already reached zero. + * Increment a percpu refcount by @nr unless its count already reached zero. * Returns %true on success; %false on failure. * * This function is safe to call as long as @ref is between init and exit. */ -static inline bool percpu_ref_tryget(struct percpu_ref *ref) +static inline bool percpu_ref_tryget_many(struct percpu_ref *ref, + unsigned long nr) { unsigned long __percpu *percpu_count; bool ret; @@ -226,10 +228,10 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref) rcu_read_lock(); if (__ref_is_percpu(ref, &percpu_count)) { - this_cpu_inc(*percpu_count); + this_cpu_add(*percpu_count, nr); ret = true; } else { - ret = atomic_long_inc_not_zero(&ref->count); + ret = atomic_long_add_unless(&ref->count, nr, 0); } rcu_read_unlock(); @@ -237,6 +239,20 @@ static inline bool percpu_ref_tryget(struct percpu_ref *ref) return ret; } +/** + * percpu_ref_tryget - try to increment a percpu refcount + * @ref: percpu_ref to try-get + * + * Increment a percpu refcount unless its count already reached zero. + * Returns %true on success; %false on failure. + * + * This function is safe to call as long as @ref is between init and exit. + */ +static inline bool percpu_ref_tryget(struct percpu_ref *ref) +{ + return percpu_ref_tryget_many(ref, 1); +} + /** * percpu_ref_tryget_live - try to increment a live percpu refcount * @ref: percpu_ref to try-get -- 2.39.5