include/linux/backing-dev.h: simplify wb_stat_sum

wb_stat_sum() disables interrupts and calls __wb_stat_sum() which
eventually calls __percpu_counter_sum().  However, the percpu routine is
already irq-safe.  Simplify the code a bit by making wb_stat_sum()
directly call percpu_counter_sum_positive() and not disable interrupts.

Also remove the now-uneeded __wb_stat_sum() which was just a wrapper
over percpu_counter_sum_positive().

Link: http://lkml.kernel.org/r/1498230681-29103-1-git-send-email-nborisov@suse.com
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 14 deletions

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index ace73f96eb1e..334165c911f0 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -104,22 +104,9 @@ static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item)
         return percpu_counter_read_positive(&wb->stat[item]);
 }
 
-static inline s64 __wb_stat_sum(struct bdi_writeback *wb,
-                                enum wb_stat_item item)
-{
-        return percpu_counter_sum_positive(&wb->stat[item]);
-}
-
 static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item)
 {
-        s64 sum;
-        unsigned long flags;
-
-        local_irq_save(flags);
-        sum = __wb_stat_sum(wb, item);
-        local_irq_restore(flags);
-
-        return sum;
+        return percpu_counter_sum_positive(&wb->stat[item]);
 }
 
 extern void wb_writeout_inc(struct bdi_writeback *wb);