linux-kernel - [PATCH] [v2] media: i2c: fix an uninitialized error code

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Date:   Fri,  4 Dec 2020 09:20:14 +0100
From:   Arnd Bergmann <arnd@...nel.org>
To:     Dongchun Zhu <dongchun.zhu@...iatek.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Nathan Chancellor <natechancellor@...il.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc:     Arnd Bergmann <arnd@...db.de>, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        clang-built-linux@...glegroups.com
Subject: [PATCH] [v2] media: i2c: fix an uninitialized error code

From: Arnd Bergmann <arnd@...db.de>

Clang points out that the error handling in ov02a10_s_stream() is
broken, and just returns a random error code:

drivers/media/i2c/ov02a10.c:537:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
        if (ov02a10->streaming == on)
            ^~~~~~~~~~~~~~~~~~~~~~~~
drivers/media/i2c/ov02a10.c:568:9: note: uninitialized use occurs here
        return ret;
               ^~~
drivers/media/i2c/ov02a10.c:537:2: note: remove the 'if' if its condition is always false
        if (ov02a10->streaming == on)
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If streaming is already on, leave it that way and return success.

Suggested-by: Dongchun Zhu <dongchun.zhu@...iatek.com>
Fixes: 91807efbe8ec ("media: i2c: add OV02A10 image sensor driver")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
v2:
- return success instead of -EBUSY, according to feedback from Dongchun Zhu
- remove incorrect advice from warning message citation
---
 drivers/media/i2c/ov02a10.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/ov02a10.c b/drivers/media/i2c/ov02a10.c
index 391718136ade..8683ffd3287a 100644
--- a/drivers/media/i2c/ov02a10.c
+++ b/drivers/media/i2c/ov02a10.c
@@ -534,8 +534,10 @@ static int ov02a10_s_stream(struct v4l2_subdev *sd, int on)
 
 	mutex_lock(&ov02a10->mutex);
 
-	if (ov02a10->streaming == on)
+	if (ov02a10->streaming == on) {
+		ret = 0;
 		goto unlock_and_return;
+	}
 
 	if (on) {
 		ret = pm_runtime_get_sync(&client->dev);
-- 
2.27.0