From: Song Liu <songliubraving@fb.com>
Date: Thu, 24 Aug 2017 09:53:59 -0700
Subject: [PATCH] md/raid5: release/flush io in raid5_do_work()
References: bnc#1060662
Patch-mainline: v4.12.14
Git-commit: 9c72a18e46ebe0f09484cce8ebf847abdab58498

commit 9c72a18e46ebe0f09484cce8ebf847abdab58498 upstream.

In raid5, there are scenarios where some ios are deferred to a later
time, and some IO need a flush to complete. To make sure we make
progress with these IOs, we need to call the following functions:

    flush_deferred_bios(conf);
    r5l_flush_stripe_to_raid(conf->log);

Both of these functions are called in raid5d(), but missing in
raid5_do_work(). As a result, these functions are not called
when multi-threading (group_thread_cnt > 0) is enabled. This patch
adds calls to these function to raid5_do_work().

Note for stable branches:

  r5l_flush_stripe_to_raid(conf->log) is need for 4.4+
  flush_deferred_bios(conf) is only needed for 4.11+

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/md/raid5.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e92dd2dc4b5a..2280bae40189 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6238,6 +6238,10 @@ static void raid5_do_work(struct work_struct *work)
 
 	spin_unlock_irq(&conf->device_lock);
 
+	flush_deferred_bios(conf);
+
+	r5l_flush_stripe_to_raid(conf->log);
+
 	async_tx_issue_pending_all();
 	blk_finish_plug(&plug);
 
-- 
2.14.2