[PATCH] ath9k: do not return invalid pointers as a *dentry

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

When calling debugfs functions, they can now return error values if
something went wrong.  If that happens, return a NULL as a *dentry to
the relay core instead of passing it an illegal pointer.

The relay core should be able to handle an illegal pointer, but add this
check to be safe.

Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: QCA ath9k Development <ath9k-devel@qca.qualcomm.com>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/wireless/ath/ath9k/common-spectral.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/common-spectral.c b/drivers/net/wireless/ath/ath9k/common-spectral.c
index 6aa3ec024ffa..21191955a7c1 100644
--- a/drivers/net/wireless/ath/ath9k/common-spectral.c
+++ b/drivers/net/wireless/ath/ath9k/common-spectral.c
@@ -1039,6 +1039,9 @@ static struct dentry *create_buf_file_handler(const char *filename,
 
 	buf_file = debugfs_create_file(filename, mode, parent, buf,
 				       &relay_file_operations);
+	if (IS_ERR(buf_file))
+		return NULL;
+
 	*is_global = 1;
 	return buf_file;
 }
-- 
2.20.1