Re: [PATCH] media: stkwebcam: move stk_camera_read_reg() scratch buffer to struct stk_camera

[Tom Rix]

On 3/12/22 11:58 AM, Pavel Skripkin wrote:
> On 3/12/22 20:30, trix@xxxxxxxxxx wrote:
> > From: Tom Rix <trix@xxxxxxxxxx>
> >
> > In stk_camera_read_reg() a single byte buffer is alloc-ed and
> > freed on every function call.  Since the size is known,
> > move the buffer to the struct stk_camera where it will be alloc-ed
> > and freed once.
> >
> > Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
> > ---
> >   drivers/media/usb/stkwebcam/stk-webcam.c | 11 ++---------
> >   drivers/media/usb/stkwebcam/stk-webcam.h |  2 ++
> >   2 files changed, 4 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/media/usb/stkwebcam/stk-webcam.c 
> > b/drivers/media/usb/stkwebcam/stk-webcam.c
> > index 5b822214ccc5c..787edb3d47c23 100644
> > --- a/drivers/media/usb/stkwebcam/stk-webcam.c
> > +++ b/drivers/media/usb/stkwebcam/stk-webcam.c
> > @@ -150,25 +150,18 @@ int stk_camera_write_reg(struct stk_camera 
> > *dev, u16 index, u8 value)
> >   int stk_camera_read_reg(struct stk_camera *dev, u16 index, u8 *value)
>
> And just random note: there are 4 possible uninit value bugs.
>
> stk_start_stream() calls stk_camera_read_reg 4 times, but ignores 
> return values.
>
> stk_camera_read_reg() should have __must_check annotation and return 
> value should be checked on each call.
>
>
> If you have time you can take care of it :) Or I will fix it one day...

These do show up in my usual static analysis and it why I was looking at 
this file.

And was sidetracked by the short malloc.

Unfortunately I looked and there are many other similar instances 
treewide ~100

These aren't caught in checkpatch, so working on that..

Tom

> With regards,
> Pavel Skripkin