[PATCH] power: supply: cpcap-battery: Fix missing nvmem_device_put() causing reference leak

[PATCH] power: supply: cpcap-battery: Fix missing nvmem_device_put() causing reference leak

[Ma Ke]

In cpcap_battery_detect_battery_type(), the reference to an nvmem
device obtained via nvmem_device_find() is not released with
nvmem_device_put() on the success or read-failure paths, causing a
permanent reference leak. The driver’s retry logic on subsequent
battery property reads can compound this leak, preventing the nvmem
device from ever being freed.

Found by code review.

Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Cc: stable@vger.kernel.org
Fixes: fd46821e85de ("power: supply: cpcap-battery: Add battery type auto detection for mapphone devices")
---
 drivers/power/supply/cpcap-battery.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/power/supply/cpcap-battery.c b/drivers/power/supply/cpcap-battery.c
index 7b7bdce3162f..59c741993ef8 100644
--- a/drivers/power/supply/cpcap-battery.c
+++ b/drivers/power/supply/cpcap-battery.c
@@ -439,10 +439,13 @@ static void cpcap_battery_detect_battery_type(struct cpcap_battery_ddata *ddata)
 	if (IS_ERR_OR_NULL(nvmem)) {
 		ddata->check_nvmem = true;
 		dev_info_once(ddata->dev, "Can not find battery nvmem device. Assuming generic lipo battery\n");
-	} else if (nvmem_device_read(nvmem, 2, 1, &battery_id) < 0) {
-		battery_id = 0;
-		ddata->check_nvmem = true;
-		dev_warn(ddata->dev, "Can not read battery nvmem device. Assuming generic lipo battery\n");
+	} else {
+		if (nvmem_device_read(nvmem, 2, 1, &battery_id) < 0) {
+			battery_id = 0;
+			ddata->check_nvmem = true;
+			dev_warn(ddata->dev, "Can not read battery nvmem device. Assuming generic lipo battery\n");
+		}
+		nvmem_device_put(nvmem);
 	}
 
 	switch (battery_id) {
-- 
2.43.0