blk-cgroup: factor out blkcg_iostat_update()

To reduce some duplicated code, factor out blkcg_iostat_update(). No
functional change.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220629070917.3113016-2-yanaijie@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 6906981563f8e24da103b970f8aeaae769fd6601..34a9452f93a7f1f9d82b8716ebdf3c988b300a8a 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -846,6 +846,21 @@ static void blkg_iostat_sub(struct blkg_iostat *dst, struct blkg_iostat *src)
        }
 }
 
+static void blkcg_iostat_update(struct blkcg_gq *blkg, struct blkg_iostat *cur,
+                               struct blkg_iostat *last)
+{
+       struct blkg_iostat delta;
+       unsigned long flags;
+
+       /* propagate percpu delta to global */
+       flags = u64_stats_update_begin_irqsave(&blkg->iostat.sync);
+       blkg_iostat_set(&delta, cur);
+       blkg_iostat_sub(&delta, last);
+       blkg_iostat_add(&blkg->iostat.cur, &delta);
+       blkg_iostat_add(last, &delta);
+       u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags);
+}
+
 static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
 {
        struct blkcg *blkcg = css_to_blkcg(css);
@@ -860,8 +875,7 @@ static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
        hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
                struct blkcg_gq *parent = blkg->parent;
                struct blkg_iostat_set *bisc = per_cpu_ptr(blkg->iostat_cpu, cpu);
-               struct blkg_iostat cur, delta;
-               unsigned long flags;
+               struct blkg_iostat cur;
                unsigned int seq;
 
                /* fetch the current per-cpu values */
@@ -870,23 +884,12 @@ static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
                        blkg_iostat_set(&cur, &bisc->cur);
                } while (u64_stats_fetch_retry(&bisc->sync, seq));
 
-               /* propagate percpu delta to global */
-               flags = u64_stats_update_begin_irqsave(&blkg->iostat.sync);
-               blkg_iostat_set(&delta, &cur);
-               blkg_iostat_sub(&delta, &bisc->last);
-               blkg_iostat_add(&blkg->iostat.cur, &delta);
-               blkg_iostat_add(&bisc->last, &delta);
-               u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags);
+               blkcg_iostat_update(blkg, &cur, &bisc->last);
 
                /* propagate global delta to parent (unless that's root) */
-               if (parent && parent->parent) {
-                       flags = u64_stats_update_begin_irqsave(&parent->iostat.sync);
-                       blkg_iostat_set(&delta, &blkg->iostat.cur);
-                       blkg_iostat_sub(&delta, &blkg->iostat.last);
-                       blkg_iostat_add(&parent->iostat.cur, &delta);
-                       blkg_iostat_add(&blkg->iostat.last, &delta);
-                       u64_stats_update_end_irqrestore(&parent->iostat.sync, flags);
-               }
+               if (parent && parent->parent)
+                       blkcg_iostat_update(parent, &blkg->iostat.cur,
+                                           &blkg->iostat.last);
        }
 
        rcu_read_unlock();