[PATCH 4/4] pcpcntr: remove percpu_counter_sum_all()

Dave Chinner
2023-03-15T08:49:58Z

From: Dave Chinner <dchinner@redhat.com>

percpu_counter_sum_all() is now redundant as the race condition it
was invented to handle is now dealt with by percpu_counter_sum()
directly and all users of percpu_counter_sum_all() have been
removed.

Remove it.

This effectively reverts the changes made in f689054aace2
("percpu_counter: add percpu_counter_sum_all interface") except for
the cpumask iteration that fixes percpu_counter_sum() made earlier
in this series.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
include/linux/percpu_counter.h | 6 -----
lib/percpu_counter.c | 40 ++++++++++------------------------
2 files changed, 11 insertions(+), 35 deletions(-)

diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 521a733e21a9..75b73c83bc9d 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -45,7 +45,6 @@ void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
void percpu_counter_add_batch(struct percpu_counter *fbc, s64 amount,
s32 batch);
s64 __percpu_counter_sum(struct percpu_counter *fbc);
-s64 percpu_counter_sum_all(struct percpu_counter *fbc);
int __percpu_counter_compare(struct percpu_counter *fbc, s64 rhs, s32 batch);
void percpu_counter_sync(struct percpu_counter *fbc);

@@ -196,11 +195,6 @@ static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
return percpu_counter_read(fbc);
}

-static inline s64 percpu_counter_sum_all(struct percpu_counter *fbc)
-{
- return percpu_counter_read(fbc);
-}
-
static inline bool percpu_counter_initialized(struct percpu_counter *fbc)
{
return true;
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 0e096311e0c0..5004463c4f9f 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -122,23 +122,6 @@ void percpu_counter_sync(struct percpu_counter *fbc)
}
EXPORT_SYMBOL(percpu_counter_sync);

-static s64 __percpu_counter_sum_mask(struct percpu_counter *fbc,
- const struct cpumask *cpu_mask)
-{
- s64 ret;
- int cpu;
- unsigned long flags;
-
- raw_spin_lock_irqsave(&fbc->lock, flags);
- ret = fbc->count;
- for_each_cpu_or(cpu, cpu_online_mask, cpu_mask) {
- s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
- ret += *pcount;
- }
- raw_spin_unlock_irqrestore(&fbc->lock, flags);
- return ret;
-}
-
/*
* Add up all the per-cpu counts, return the result. This is a more accurate
* but much slower version of percpu_counter_read_positive().
@@ -153,22 +136,21 @@ static s64 __percpu_counter_sum_mask(struct percpu_counter *fbc,
*/
s64 __percpu_counter_sum(struct percpu_counter *fbc)
{
+ s64 ret;
+ int cpu;
+ unsigned long flags;

- return __percpu_counter_sum_mask(fbc, cpu_dying_mask);
+ raw_spin_lock_irqsave(&fbc->lock, flags);
+ ret = fbc->count;
+ for_each_cpu_or(cpu, cpu_online_mask, cpu_dying_mask) {
+ s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
+ ret += *pcount;
+ }
+ raw_spin_unlock_irqrestore(&fbc->lock, flags);
+ return ret;
}
EXPORT_SYMBOL(__percpu_counter_sum);

-/*
- * This is slower version of percpu_counter_sum as it traverses all possible
- * cpus. Use this only in the cases where accurate data is needed in the
- * presense of CPUs getting offlined.
- */
-s64 percpu_counter_sum_all(struct percpu_counter *fbc)
-{
- return __percpu_counter_sum_mask(fbc, cpu_possible_mask);
-}
-EXPORT_SYMBOL(percpu_counter_sum_all);
-
int __percpu_counter_init(struct percpu_counter *fbc, s64 amount, gfp_t gfp,
struct lock_class_key *key)
{
--
2.39.2