From: Kent Overstreet <kmo@daterainc.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, axboe@kernel.dk, hch@infradead.org,
hannes@cmpxchg.org
Subject: Re: [PATCH 1/9] percpu_ref: relocate percpu_ref_reinit()
Date: Tue, 23 Sep 2014 14:07:53 -0700 [thread overview]
Message-ID: <20140923210753.GB15142@kmo-pixel> (raw)
In-Reply-To: <1411451718-17807-2-git-send-email-tj@kernel.org>
On Tue, Sep 23, 2014 at 01:55:10AM -0400, Tejun Heo wrote:
> percpu_ref is gonna go through restructuring. Move
> percpu_ref_reinit() after percpu_ref_kill_and_confirm(). This will
> make later changes easier to follow and result in cleaner
> organization.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Kent Overstreet <kmo@daterainc.com>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
> ---
> include/linux/percpu-refcount.h | 2 +-
> lib/percpu-refcount.c | 70 ++++++++++++++++++++---------------------
> 2 files changed, 36 insertions(+), 36 deletions(-)
>
> diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
> index 5df6784..f015f13 100644
> --- a/include/linux/percpu-refcount.h
> +++ b/include/linux/percpu-refcount.h
> @@ -68,10 +68,10 @@ struct percpu_ref {
>
> int __must_check percpu_ref_init(struct percpu_ref *ref,
> percpu_ref_func_t *release, gfp_t gfp);
> -void percpu_ref_reinit(struct percpu_ref *ref);
> void percpu_ref_exit(struct percpu_ref *ref);
> void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
> percpu_ref_func_t *confirm_kill);
> +void percpu_ref_reinit(struct percpu_ref *ref);
>
> /**
> * percpu_ref_kill - drop the initial ref
> diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
> index 559ee0b..070dab5 100644
> --- a/lib/percpu-refcount.c
> +++ b/lib/percpu-refcount.c
> @@ -63,41 +63,6 @@ int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release,
> EXPORT_SYMBOL_GPL(percpu_ref_init);
>
> /**
> - * percpu_ref_reinit - re-initialize a percpu refcount
> - * @ref: perpcu_ref to re-initialize
> - *
> - * Re-initialize @ref so that it's in the same state as when it finished
> - * percpu_ref_init(). @ref must have been initialized successfully, killed
> - * and reached 0 but not exited.
> - *
> - * Note that percpu_ref_tryget[_live]() are safe to perform on @ref while
> - * this function is in progress.
> - */
> -void percpu_ref_reinit(struct percpu_ref *ref)
> -{
> - unsigned long __percpu *pcpu_count = pcpu_count_ptr(ref);
> - int cpu;
> -
> - BUG_ON(!pcpu_count);
> - WARN_ON(!percpu_ref_is_zero(ref));
> -
> - atomic_long_set(&ref->count, 1 + PCPU_COUNT_BIAS);
> -
> - /*
> - * Restore per-cpu operation. smp_store_release() is paired with
> - * smp_read_barrier_depends() in __pcpu_ref_alive() and guarantees
> - * that the zeroing is visible to all percpu accesses which can see
> - * the following PCPU_REF_DEAD clearing.
> - */
> - for_each_possible_cpu(cpu)
> - *per_cpu_ptr(pcpu_count, cpu) = 0;
> -
> - smp_store_release(&ref->pcpu_count_ptr,
> - ref->pcpu_count_ptr & ~PCPU_REF_DEAD);
> -}
> -EXPORT_SYMBOL_GPL(percpu_ref_reinit);
> -
> -/**
> * percpu_ref_exit - undo percpu_ref_init()
> * @ref: percpu_ref to exit
> *
> @@ -189,3 +154,38 @@ void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
> call_rcu_sched(&ref->rcu, percpu_ref_kill_rcu);
> }
> EXPORT_SYMBOL_GPL(percpu_ref_kill_and_confirm);
> +
> +/**
> + * percpu_ref_reinit - re-initialize a percpu refcount
> + * @ref: perpcu_ref to re-initialize
> + *
> + * Re-initialize @ref so that it's in the same state as when it finished
> + * percpu_ref_init(). @ref must have been initialized successfully, killed
> + * and reached 0 but not exited.
> + *
> + * Note that percpu_ref_tryget[_live]() are safe to perform on @ref while
> + * this function is in progress.
> + */
> +void percpu_ref_reinit(struct percpu_ref *ref)
> +{
> + unsigned long __percpu *pcpu_count = pcpu_count_ptr(ref);
> + int cpu;
> +
> + BUG_ON(!pcpu_count);
> + WARN_ON(!percpu_ref_is_zero(ref));
> +
> + atomic_long_set(&ref->count, 1 + PCPU_COUNT_BIAS);
> +
> + /*
> + * Restore per-cpu operation. smp_store_release() is paired with
> + * smp_read_barrier_depends() in __pcpu_ref_alive() and guarantees
> + * that the zeroing is visible to all percpu accesses which can see
> + * the following PCPU_REF_DEAD clearing.
> + */
> + for_each_possible_cpu(cpu)
> + *per_cpu_ptr(pcpu_count, cpu) = 0;
> +
> + smp_store_release(&ref->pcpu_count_ptr,
> + ref->pcpu_count_ptr & ~PCPU_REF_DEAD);
> +}
> +EXPORT_SYMBOL_GPL(percpu_ref_reinit);
> --
> 1.9.3
>
next prev parent reply other threads:[~2014-09-23 21:06 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-23 5:55 [PATCHSET percpu/for-3.18] percpu_ref: implement switch_to_atomic/percpu() Tejun Heo
2014-09-23 5:55 ` [PATCH 1/9] percpu_ref: relocate percpu_ref_reinit() Tejun Heo
2014-09-23 21:01 ` Kent Overstreet
2014-09-23 21:07 ` Kent Overstreet [this message]
2014-09-23 5:55 ` [PATCH 2/9] percpu_ref: minor code and comment updates Tejun Heo
2014-09-23 21:09 ` Kent Overstreet
2014-09-23 5:55 ` [PATCH 3/9] percpu_ref: replace pcpu_ prefix with percpu_ Tejun Heo
2014-09-23 21:10 ` Kent Overstreet
2014-09-23 5:55 ` [PATCH 4/9] percpu_ref: rename things to prepare for decoupling percpu/atomic mode switch Tejun Heo
2014-09-23 21:11 ` Kent Overstreet
2014-09-23 5:55 ` [PATCH 5/9] percpu_ref: add PCPU_REF_DEAD Tejun Heo
2014-09-23 13:48 ` [PATCH v2 " Tejun Heo
2014-09-23 21:14 ` Kent Overstreet
2014-09-23 5:55 ` [PATCH 6/9] percpu_ref: decouple switching to atomic mode and killing Tejun Heo
2014-09-23 21:13 ` Kent Overstreet
2014-09-23 5:55 ` [PATCH 7/9] percpu_ref: decouple switching to percpu mode and reinit Tejun Heo
2014-09-23 13:49 ` [PATCH v2 " Tejun Heo
2014-09-23 21:15 ` Kent Overstreet
2014-09-23 5:55 ` [PATCH 8/9] percpu_ref: add PERCPU_REF_INIT_* flags Tejun Heo
2014-09-23 21:16 ` Kent Overstreet
2014-09-23 5:55 ` [PATCH 9/9] percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky Tejun Heo
2014-09-23 21:17 ` Kent Overstreet
2014-09-24 17:32 ` [PATCHSET percpu/for-3.18] percpu_ref: implement switch_to_atomic/percpu() Tejun Heo
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