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Subject[PATCH] staging: atomisp: move null check to earlier point
Date
`find_gmin_subdev` function that returns a pointer to `struct
gmin_subdev` can return NULL.

In `gmin_v2p8_ctrl` there's a call to this function but the possibility
of a NULL was not checked before its being dereferenced. ie:

```
/* Acquired here --------v */
struct gmin_subdev *gs = find_gmin_subdev(subdev);
int ret;
int value;

/* v------Dereferenced here */
if (gs->v2p8_gpio >= 0) {
pr_info("atomisp_gmin_platform: 2.8v power on GPIO %d\n",
gs->v2p8_gpio);
ret = gpio_request(gs->v2p8_gpio, "camera_v2p8");
if (!ret)
ret = gpio_direction_output(gs->v2p8_gpio, 0);
if (ret)
pr_err("V2P8 GPIO initialization failed\n");
}
```

I have moved the NULL check before deref point.

Caught-by: Coverity Static Analyzer CID 1465536
Signed-off-by: Cengiz Can <cengiz@kernel.wtf>
---
drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
index 0df46a1af5f0..8e9c5016f299 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
@@ -871,6 +871,11 @@ static int gmin_v2p8_ctrl(struct v4l2_subdev *subdev, int on)
int ret;
int value;

+ if (!gs) {
+ pr_err("Unable to find gmin subdevice\n");
+ return -EINVAL;
+ }
+
if (gs->v2p8_gpio >= 0) {
pr_info("atomisp_gmin_platform: 2.8v power on GPIO %d\n",
gs->v2p8_gpio);
@@ -881,7 +886,7 @@ static int gmin_v2p8_ctrl(struct v4l2_subdev *subdev, int on)
pr_err("V2P8 GPIO initialization failed\n");
}

- if (!gs || gs->v2p8_on == on)
+ if (gs->v2p8_on == on)
return 0;
gs->v2p8_on = on;

--
2.27.0
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