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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Sahitya Tummala <stummala@codeaurora.org>,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Sasha Levin <sashal@kernel.org>,
        linux-f2fs-devel@lists.sourceforge.net
Subject: [PATCH AUTOSEL 4.9 15/87] f2fs: do not use mutex lock in atomic context
Date:   Wed, 27 Mar 2019 14:19:28 -0400
Message-Id: <20190327182040.17444-15-sashal@kernel.org>
In-Reply-To: <20190327182040.17444-1-sashal@kernel.org>
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From: Sahitya Tummala <stummala@codeaurora.org>

[ Upstream commit 9083977dabf3833298ddcd40dee28687f1e6b483 ]

Fix below warning coming because of using mutex lock in atomic context.

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:98
in_atomic(): 1, irqs_disabled(): 0, pid: 585, name: sh
Preemption disabled at: __radix_tree_preload+0x28/0x130
Call trace:
 dump_backtrace+0x0/0x2b4
 show_stack+0x20/0x28
 dump_stack+0xa8/0xe0
 ___might_sleep+0x144/0x194
 __might_sleep+0x58/0x8c
 mutex_lock+0x2c/0x48
 f2fs_trace_pid+0x88/0x14c
 f2fs_set_node_page_dirty+0xd0/0x184

Do not use f2fs_radix_tree_insert() to avoid doing cond_resched() with
spin_lock() acquired.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/trace.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/trace.c b/fs/f2fs/trace.c
index 73b4e1d1912a..501c283761d2 100644
--- a/fs/f2fs/trace.c
+++ b/fs/f2fs/trace.c
@@ -61,6 +61,7 @@ void f2fs_trace_pid(struct page *page)
 
 	page->private = pid;
 
+retry:
 	if (radix_tree_preload(GFP_NOFS))
 		return;
 
@@ -71,7 +72,12 @@ void f2fs_trace_pid(struct page *page)
 	if (p)
 		radix_tree_delete(&pids, pid);
 
-	f2fs_radix_tree_insert(&pids, pid, current);
+	if (radix_tree_insert(&pids, pid, current)) {
+		spin_unlock(&pids_lock);
+		radix_tree_preload_end();
+		cond_resched();
+		goto retry;
+	}
 
 	trace_printk("%3x:%3x %4x %-16s\n",
 			MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
-- 
2.19.1