linux-kernel - [PATCH 4.4 026/114] btrfs: cleaner_kthread() doesnt need explicit freeze

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Message-Id: <20181108215101.483013816@linuxfoundation.org>
Date:   Thu,  8 Nov 2018 13:50:41 -0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jiri Kosina <jkosina@...e.cz>,
        David Sterba <dsterba@...e.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.4 026/114] btrfs: cleaner_kthread() doesnt need explicit freeze

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 838fe1887765f4cc679febea60d87d2a06bd300e ]

cleaner_kthread() is not marked freezable, and therefore calling
try_to_freeze() in its context is a pointless no-op.

In addition to that, as has been clearly demonstrated by 80ad623edd2d
("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"), it's perfectly
valid / legal for cleaner_kthread() to stay scheduled out in an arbitrary
place during suspend (in that particular example that was waiting for
reading of extent pages), so there is no need to leave any traces of
freezer in this kthread.

Fixes: 80ad623edd2d ("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()")
Fixes: 696249132158 ("btrfs: clear PF_NOFREEZE in cleaner_kthread()")
Signed-off-by: Jiri Kosina <jkosina@...e.cz>
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/btrfs/disk-io.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ae6e3a30e61e..a2001abbe379 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1820,7 +1820,7 @@ static int cleaner_kthread(void *arg)
 		 */
 		btrfs_delete_unused_bgs(root->fs_info);
 sleep:
-		if (!try_to_freeze() && !again) {
+		if (!again) {
 			set_current_state(TASK_INTERRUPTIBLE);
 			if (!kthread_should_stop())
 				schedule();
-- 
2.17.1