[PATCH] block: skip cgroups for passthrough io

[Kanchan Joshi <joshi.k@samsung.com>]

From: Kundan Kumar <kundan.kumar@samsung.com>

Even if BLK_CGROUP is enabled, it does not work for passthrough io.
So skip setting up blkg for passthrough bio.

Reduced processing gives ~5% hike in peak-performance workload.

Signed-off-by: Kundan Kumar <kundan.kumar@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
---
 block/blk-cgroup.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 4b48c2c44098..58b13ef23821 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -2064,6 +2064,9 @@ void bio_associate_blkg(struct bio *bio)
 {
 	struct cgroup_subsys_state *css;
 
+	if (blk_op_is_passthrough(bio->bi_opf))
+		return;
+
 	rcu_read_lock();
 
 	if (bio->bi_blkg)
-- 
2.25.1