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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 <asml.silence@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Dennis Zhou <dennis@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2019-12-28 14:13:02 +03:00 committed by Jens Axboe
parent c1ca757bd6
commit 4e5ef02317
1 changed files with 31 additions and 15 deletions
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46
include/linux/percpu-refcount.h
View File

@ -209,6 +209,36 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
percpu_ref_get_many(ref, 1);
}
/**
* 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 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_many(struct percpu_ref *ref,
unsigned long nr)
{
unsigned long __percpu *percpu_count;
bool ret;
rcu_read_lock();
if (__ref_is_percpu(ref, &percpu_count)) {
this_cpu_add(*percpu_count, nr);
ret = true;
} else {
ret = atomic_long_add_unless(&ref->count, nr, 0);
}
rcu_read_unlock();
return ret;
}
/**
* percpu_ref_tryget - try to increment a percpu refcount
* @ref: percpu_ref to try-get
@ -220,21 +250,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref)
*/
static inline bool percpu_ref_tryget(struct percpu_ref *ref)
{
unsigned long __percpu *percpu_count;
bool ret;
rcu_read_lock();
if (__ref_is_percpu(ref, &percpu_count)) {
this_cpu_inc(*percpu_count);
ret = true;
} else {
ret = atomic_long_inc_not_zero(&ref->count);
}
rcu_read_unlock();
return ret;
return percpu_ref_tryget_many(ref, 1);
}
/**