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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>,
        Liang He <windhl@126.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>
Subject: [PATCH 4.9 003/101] scsi: ufs: host: Hold reference returned by of_parse_phandle()
Date:   Tue, 23 Aug 2022 10:02:36 +0200
Message-Id: <20220823080034.726420269@linuxfoundation.org>
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From: Liang He <windhl@126.com>

commit a3435afba87dc6cd83f5595e7607f3c40f93ef01 upstream.

In ufshcd_populate_vreg(), we should hold the reference returned by
of_parse_phandle() and then use it to call of_node_put() for refcount
balance.

Link: https://lore.kernel.org/r/20220719071529.1081166-1-windhl@126.com
Fixes: aa4976130934 ("ufs: Add regulator enable support")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Liang He <windhl@126.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/scsi/ufs/ufshcd-pltfrm.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -126,9 +126,20 @@ out:
 	return ret;
 }
 
+static bool phandle_exists(const struct device_node *np,
+			   const char *phandle_name, int index)
+{
+	struct device_node *parse_np = of_parse_phandle(np, phandle_name, index);
+
+	if (parse_np)
+		of_node_put(parse_np);
+
+	return parse_np != NULL;
+}
+
 #define MAX_PROP_SIZE 32
 static int ufshcd_populate_vreg(struct device *dev, const char *name,
-		struct ufs_vreg **out_vreg)
+				struct ufs_vreg **out_vreg)
 {
 	int ret = 0;
 	char prop_name[MAX_PROP_SIZE];
@@ -141,7 +152,7 @@ static int ufshcd_populate_vreg(struct d
 	}
 
 	snprintf(prop_name, MAX_PROP_SIZE, "%s-supply", name);
-	if (!of_parse_phandle(np, prop_name, 0)) {
+	if (!phandle_exists(np, prop_name, 0)) {
 		dev_info(dev, "%s: Unable to find %s regulator, assuming enabled\n",
 				__func__, prop_name);
 		goto out;