linux-kernel - [PATCH] writeback: clear auto

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Date:   Tue, 18 Aug 2020 07:13:30 -0700
From:   trix@...hat.com
To:     viro@...iv.linux.org.uk
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Tom Rix <trix@...hat.com>
Subject: [PATCH] writeback: clear auto_free in initializaiton

From: Tom Rix <trix@...hat.com>

Review fs/fs-writeback.c bdi_split_work_to_wbs
The CONFIG_CGROUP_WRITEBACK version contains this line
	base_work->auto_free = 0;
Which seems like a strange place to set auto_free as
it is not where the rest of base_work is initialized.

In the default version of bdi_split_work_to_wbs, if a
successful malloc happens, base_work is copied and
auto_free is set to 1, else the base_work is
copied to another local valarible and its auto_free
is set to 0.

So move the clearing of auto_free to the
initialization of the local base_work structures.

Signed-off-by: Tom Rix <trix@...hat.com>
---
 fs/fs-writeback.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index a605c3dddabc..fa1106de2ab0 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -881,7 +881,6 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
 		work = &fallback_work;
 		*work = *base_work;
 		work->nr_pages = nr_pages;
-		work->auto_free = 0;
 		work->done = &fallback_work_done;
 
 		wb_queue_work(wb, work);
@@ -1055,10 +1054,8 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
 {
 	might_sleep();
 
-	if (!skip_if_busy || !writeback_in_progress(&bdi->wb)) {
-		base_work->auto_free = 0;
+	if (!skip_if_busy || !writeback_in_progress(&bdi->wb))
 		wb_queue_work(&bdi->wb, base_work);
-	}
 }
 
 #endif	/* CONFIG_CGROUP_WRITEBACK */
@@ -2459,6 +2456,7 @@ static void __writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr,
 		.done			= &done,
 		.nr_pages		= nr,
 		.reason			= reason,
+		.auto_free		= 0,
 	};
 
 	if (!bdi_has_dirty_io(bdi) || bdi == &noop_backing_dev_info)
@@ -2538,6 +2536,7 @@ void sync_inodes_sb(struct super_block *sb)
 		.done		= &done,
 		.reason		= WB_REASON_SYNC,
 		.for_sync	= 1,
+		.auto_free	= 0,
 	};
 
 	/*
-- 
2.18.1