linux-kernel - [PATCH] mm/cma_debug: Check for null tmp in cma_debugfs_add

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Date:   Thu, 21 Feb 2019 12:01:30 +0800
From:   Yue Hu <zbestahu@...il.com>
To:     akpm@...ux-foundation.org, mhocko@...e.com, rientjes@...gle.com,
        joe@...ches.com
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org, huyue2@...ong.com
Subject: [PATCH] mm/cma_debug: Check for null tmp in cma_debugfs_add_one()

From: Yue Hu <huyue2@...ong.com>

If debugfs_create_dir() failed, the following debugfs_create_file()
will be meanless since it depends on non-NULL tmp dentry and it will
only waste CPU resource.

Signed-off-by: Yue Hu <huyue2@...ong.com>
---
 mm/cma_debug.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/cma_debug.c b/mm/cma_debug.c
index 2c2c869..3e9d984 100644
--- a/mm/cma_debug.c
+++ b/mm/cma_debug.c
@@ -169,6 +169,8 @@ static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry)
 	scnprintf(name, sizeof(name), "cma-%s", cma->name);
 
 	tmp = debugfs_create_dir(name, root_dentry);
+	if (!tmp)
+		return;
 
 	debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops);
 	debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops);
-- 
1.9.1