On Tue, Sep 23, 2014 at 01:55:13AM -0400, Tejun Heo wrote: > percpu_ref will be restructured so that percpu/atomic mode switching > and reference killing are dedoupled. In preparation, do the following > renames. > > * percpu_ref->confirm_kill -> percpu_ref->confirm_switch > * __PERCPU_REF_DEAD -> __PERCPU_REF_ATOMIC > * __percpu_ref_alive() -> __ref_is_percpu() > > This patch is pure rename and doesn't introduce any functional > changes. > > Signed-off-by: Tejun Heo <t...@kernel.org> > Cc: Kent Overstreet <k...@daterainc.com>
Reviewed-by: Kent Overstreet <k...@daterainc.com> > --- > include/linux/percpu-refcount.h | 25 ++++++++++++++----------- > lib/percpu-refcount.c | 22 +++++++++++----------- > 2 files changed, 25 insertions(+), 22 deletions(-) > > diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h > index 3d463a3..910e5f7 100644 > --- a/include/linux/percpu-refcount.h > +++ b/include/linux/percpu-refcount.h > @@ -54,6 +54,11 @@ > struct percpu_ref; > typedef void (percpu_ref_func_t)(struct percpu_ref *); > > +/* flags set in the lower bits of percpu_ref->percpu_count_ptr */ > +enum { > + __PERCPU_REF_ATOMIC = 1LU << 0, /* operating in atomic mode */ > +}; > + > struct percpu_ref { > atomic_long_t count; > /* > @@ -62,7 +67,7 @@ struct percpu_ref { > */ > unsigned long percpu_count_ptr; > percpu_ref_func_t *release; > - percpu_ref_func_t *confirm_kill; > + percpu_ref_func_t *confirm_switch; > struct rcu_head rcu; > }; > > @@ -88,23 +93,21 @@ static inline void percpu_ref_kill(struct percpu_ref *ref) > return percpu_ref_kill_and_confirm(ref, NULL); > } > > -#define __PERCPU_REF_DEAD 1 > - > /* > * Internal helper. Don't use outside percpu-refcount proper. The > * function doesn't return the pointer and let the caller test it for NULL > * because doing so forces the compiler to generate two conditional > * branches as it can't assume that @ref->percpu_count is not NULL. > */ > -static inline bool __percpu_ref_alive(struct percpu_ref *ref, > - unsigned long __percpu **percpu_countp) > +static inline bool __ref_is_percpu(struct percpu_ref *ref, > + unsigned long __percpu > **percpu_countp) > { > unsigned long percpu_ptr = ACCESS_ONCE(ref->percpu_count_ptr); > > /* paired with smp_store_release() in percpu_ref_reinit() */ > smp_read_barrier_depends(); > > - if (unlikely(percpu_ptr & __PERCPU_REF_DEAD)) > + if (unlikely(percpu_ptr & __PERCPU_REF_ATOMIC)) > return false; > > *percpu_countp = (unsigned long __percpu *)percpu_ptr; > @@ -125,7 +128,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref) > > rcu_read_lock_sched(); > > - if (__percpu_ref_alive(ref, &percpu_count)) > + if (__ref_is_percpu(ref, &percpu_count)) > this_cpu_inc(*percpu_count); > else > atomic_long_inc(&ref->count); > @@ -149,7 +152,7 @@ static inline bool percpu_ref_tryget(struct percpu_ref > *ref) > > rcu_read_lock_sched(); > > - if (__percpu_ref_alive(ref, &percpu_count)) { > + if (__ref_is_percpu(ref, &percpu_count)) { > this_cpu_inc(*percpu_count); > ret = true; > } else { > @@ -183,7 +186,7 @@ static inline bool percpu_ref_tryget_live(struct > percpu_ref *ref) > > rcu_read_lock_sched(); > > - if (__percpu_ref_alive(ref, &percpu_count)) { > + if (__ref_is_percpu(ref, &percpu_count)) { > this_cpu_inc(*percpu_count); > ret = true; > } > @@ -208,7 +211,7 @@ static inline void percpu_ref_put(struct percpu_ref *ref) > > rcu_read_lock_sched(); > > - if (__percpu_ref_alive(ref, &percpu_count)) > + if (__ref_is_percpu(ref, &percpu_count)) > this_cpu_dec(*percpu_count); > else if (unlikely(atomic_long_dec_and_test(&ref->count))) > ref->release(ref); > @@ -228,7 +231,7 @@ static inline bool percpu_ref_is_zero(struct percpu_ref > *ref) > { > unsigned long __percpu *percpu_count; > > - if (__percpu_ref_alive(ref, &percpu_count)) > + if (__ref_is_percpu(ref, &percpu_count)) > return false; > return !atomic_long_read(&ref->count); > } > diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c > index 5aea6b7..7aef590 100644 > --- a/lib/percpu-refcount.c > +++ b/lib/percpu-refcount.c > @@ -34,7 +34,7 @@ > static unsigned long __percpu *percpu_count_ptr(struct percpu_ref *ref) > { > return (unsigned long __percpu *) > - (ref->percpu_count_ptr & ~__PERCPU_REF_DEAD); > + (ref->percpu_count_ptr & ~__PERCPU_REF_ATOMIC); > } > > /** > @@ -80,7 +80,7 @@ void percpu_ref_exit(struct percpu_ref *ref) > > if (percpu_count) { > free_percpu(percpu_count); > - ref->percpu_count_ptr = __PERCPU_REF_DEAD; > + ref->percpu_count_ptr = __PERCPU_REF_ATOMIC; > } > } > EXPORT_SYMBOL_GPL(percpu_ref_exit); > @@ -117,8 +117,8 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu) > ref->release, atomic_long_read(&ref->count)); > > /* @ref is viewed as dead on all CPUs, send out kill confirmation */ > - if (ref->confirm_kill) > - ref->confirm_kill(ref); > + if (ref->confirm_switch) > + ref->confirm_switch(ref); > > /* > * Now we're in single atomic_long_t mode with a consistent > @@ -145,11 +145,11 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu) > void percpu_ref_kill_and_confirm(struct percpu_ref *ref, > percpu_ref_func_t *confirm_kill) > { > - WARN_ONCE(ref->percpu_count_ptr & __PERCPU_REF_DEAD, > + WARN_ONCE(ref->percpu_count_ptr & __PERCPU_REF_ATOMIC, > "%s called more than once on %pf!", __func__, ref->release); > > - ref->percpu_count_ptr |= __PERCPU_REF_DEAD; > - ref->confirm_kill = confirm_kill; > + ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC; > + ref->confirm_switch = confirm_kill; > > call_rcu_sched(&ref->rcu, percpu_ref_kill_rcu); > } > @@ -178,14 +178,14 @@ void percpu_ref_reinit(struct percpu_ref *ref) > > /* > * Restore per-cpu operation. smp_store_release() is paired with > - * smp_read_barrier_depends() in __percpu_ref_alive() and > - * guarantees that the zeroing is visible to all percpu accesses > - * which can see the following __PERCPU_REF_DEAD clearing. > + * smp_read_barrier_depends() in __ref_is_percpu() and guarantees > + * that the zeroing is visible to all percpu accesses which can see > + * the following __PERCPU_REF_ATOMIC clearing. > */ > for_each_possible_cpu(cpu) > *per_cpu_ptr(percpu_count, cpu) = 0; > > smp_store_release(&ref->percpu_count_ptr, > - ref->percpu_count_ptr & ~__PERCPU_REF_DEAD); > + ref->percpu_count_ptr & ~__PERCPU_REF_ATOMIC); > } > EXPORT_SYMBOL_GPL(percpu_ref_reinit); > -- > 1.9.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/