Em Tue, 19 Dec 2017 10:24:51 +0200
Sakari Ailus <sakari.ailus@xxxxxx> escreveu:
> On Mon, Dec 18, 2017 at 05:27:04PM -0200, Mauro Carvalho Chehab wrote:
> > Em Mon, 9 Oct 2017 23:23:56 +0300
> > Sakari Ailus <sakari.ailus@xxxxxx> escreveu:
> >
> > > Hi Mauro,
> > >
> > > On Mon, Oct 09, 2017 at 07:19:21AM -0300, Mauro Carvalho Chehab wrote:
> > > > The __V4L2_SUBDEV_MK_GET_TRY() macro is used to define
> > > > 3 functions that have the same arguments. The code of those
> > > > functions is simple enough to just declare them, de-obfuscating
> > > > the code.
> > > >
> > > > While here, replace BUG_ON() by WARN_ON() as there's no reason
> > > > why to panic the Kernel if this fails.
> > >
> > > BUG_ON() might actually be a better idea as this will lead to memory
> > > corruption. I presume it's not been hit often.
> >
> > Well, let's then change the code to:
> >
> > if (WARN_ON(pad >= sd->entity.num_pads))
> > return -EINVAL;
> >
> > This way, it won't try to use an invalid value. As those are default
> > handlers for ioctls, userspace should be able to handle it.
>
> Another approach would be to return the entry for a valid pad. Few if any
> drivers perform error handling on the value returned for the simple reason
> that they know how many pads their own entities have.
Well, they should check for errors on returned values :-)
Anyway, I guess that using pad=0 as a way to avoid Kernel crashes
is not a bad idea.
Patch enclosed. It replaces patch 6/8.
Thanks,
Mauro
[PATCH] media: v4l2-subdev: get rid of __V4L2_SUBDEV_MK_GET_TRY() macro
The __V4L2_SUBDEV_MK_GET_TRY() macro is used to define
3 functions that have the same arguments. The code of those
functions is simple enough to just declare them, de-obfuscating
the code.
While here, replace BUG_ON() by WARN_ON() as there's no reason
why to panic the Kernel if this fails.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 71b8ff4b2e0e..443e5e019006 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -896,19 +896,35 @@ struct v4l2_subdev_fh {
container_of(fh, struct v4l2_subdev_fh, vfh)
#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
-#define __V4L2_SUBDEV_MK_GET_TRY(rtype, fun_name, field_name) \
- static inline struct rtype * \
- fun_name(struct v4l2_subdev *sd, \
- struct v4l2_subdev_pad_config *cfg, \
- unsigned int pad) \
- { \
- BUG_ON(pad >= sd->entity.num_pads); \
- return &cfg[pad].field_name; \
- }
+static inline struct v4l2_mbus_framefmt
+*v4l2_subdev_get_try_format(struct v4l2_subdev *sd,
+ struct v4l2_subdev_pad_config *cfg,
+ unsigned int pad)
+{
+ if (WARN_ON(pad >= sd->entity.num_pads))
+ pad = 0;
+ return &cfg[pad].try_fmt;
+}
+
+static inline struct v4l2_rect
+*v4l2_subdev_get_try_crop(struct v4l2_subdev *sd,
+ struct v4l2_subdev_pad_config *cfg,
+ unsigned int pad)
+{
+ if (WARN_ON(pad >= sd->entity.num_pads))
+ pad = 0;
+ return &cfg[pad].try_crop;
+}
-__V4L2_SUBDEV_MK_GET_TRY(v4l2_mbus_framefmt, v4l2_subdev_get_try_format, try_fmt)
-__V4L2_SUBDEV_MK_GET_TRY(v4l2_rect, v4l2_subdev_get_try_crop, try_crop)
-__V4L2_SUBDEV_MK_GET_TRY(v4l2_rect, v4l2_subdev_get_try_compose, try_compose)
+static inline struct v4l2_rect
+*v4l2_subdev_get_try_compose(struct v4l2_subdev *sd,
+ struct v4l2_subdev_pad_config *cfg,
+ unsigned int pad)
+{
+ if (WARN_ON(pad >= sd->entity.num_pads))
+ pad = 0;
+ return &cfg[pad].try_compose;
+}
#endif
extern const struct v4l2_file_operations v4l2_subdev_fops;
