| Message ID | 20240410-enable-streams-impro-v3-4-e5e7a5da7420@ideasonboard.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | media: subdev: Improve stream enable/disable machinery | expand |
Hi Tomi, Thank you for the patch On 10/04/24 6:05 pm, Tomi Valkeinen wrote: > call_s_stream() uses sd->enabled_streams to track whether streaming has > already been enabled. However, > v4l2_subdev_enable/disable_streams_fallback(), which was the original > user of this field, already uses it, and > v4l2_subdev_enable/disable_streams_fallback() will call call_s_stream(). > > This leads to a conflict as both functions set the field. Afaics, both > functions set the field to the same value, so it won't cause a runtime > bug, but it's still wrong and if we, e.g., change how > v4l2_subdev_enable/disable_streams_fallback() operates we might easily > cause bugs. > > Fix this by adding a new field, 'streaming_enabled', for > call_s_stream(). Just a suggestion, as this is only used in call_s_stream(), maybe naming this field 's_stream_enabled' ? Rest looks good to me, Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> > > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> > --- > drivers/media/v4l2-core/v4l2-subdev.c | 8 ++------ > include/media/v4l2-subdev.h | 3 +++ > 2 files changed, 5 insertions(+), 6 deletions(-) > > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c > index 606a909cd778..6cd353d83dfc 100644 > --- a/drivers/media/v4l2-core/v4l2-subdev.c > +++ b/drivers/media/v4l2-core/v4l2-subdev.c > @@ -421,12 +421,8 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable) > * The .s_stream() operation must never be called to start or stop an > * already started or stopped subdev. Catch offenders but don't return > * an error yet to avoid regressions. > - * > - * As .s_stream() is mutually exclusive with the .enable_streams() and > - * .disable_streams() operation, we can use the enabled_streams field > - * to store the subdev streaming state. > */ > - if (WARN_ON(!!sd->enabled_streams == !!enable)) > + if (WARN_ON(sd->streaming_enabled == !!enable)) > return 0; > > ret = sd->ops->video->s_stream(sd, enable); > @@ -437,7 +433,7 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable) > } > > if (!ret) { > - sd->enabled_streams = enable ? BIT(0) : 0; > + sd->streaming_enabled = enable; > > if (enable) > v4l2_subdev_enable_privacy_led(sd); > diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h > index a9e6b8146279..f55d03e0acc1 100644 > --- a/include/media/v4l2-subdev.h > +++ b/include/media/v4l2-subdev.h > @@ -1043,6 +1043,8 @@ struct v4l2_subdev_platform_data { > * v4l2_subdev_enable_streams() and > * v4l2_subdev_disable_streams() helper functions for fallback > * cases. > + * @streaming_enabled: Tracks whether streaming has been enabled with s_stream. > + * This is only for call_s_stream() internal use. > * > * Each instance of a subdev driver should create this struct, either > * stand-alone or embedded in a larger struct. > @@ -1091,6 +1093,7 @@ struct v4l2_subdev { > */ > struct v4l2_subdev_state *active_state; > u64 enabled_streams; > + bool streaming_enabled; > }; > > >
On 11/04/2024 08:16, Umang Jain wrote: > Hi Tomi, > > Thank you for the patch > > On 10/04/24 6:05 pm, Tomi Valkeinen wrote: >> call_s_stream() uses sd->enabled_streams to track whether streaming has >> already been enabled. However, >> v4l2_subdev_enable/disable_streams_fallback(), which was the original >> user of this field, already uses it, and >> v4l2_subdev_enable/disable_streams_fallback() will call call_s_stream(). >> >> This leads to a conflict as both functions set the field. Afaics, both >> functions set the field to the same value, so it won't cause a runtime >> bug, but it's still wrong and if we, e.g., change how >> v4l2_subdev_enable/disable_streams_fallback() operates we might easily >> cause bugs. >> >> Fix this by adding a new field, 'streaming_enabled', for >> call_s_stream(). > > Just a suggestion, as this is only used in call_s_stream(), maybe naming > this field 's_stream_enabled' ? Yes, I think that's a good idea. Tomi > Rest looks good to me, > > Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> > >> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> >> --- >> drivers/media/v4l2-core/v4l2-subdev.c | 8 ++------ >> include/media/v4l2-subdev.h | 3 +++ >> 2 files changed, 5 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c >> b/drivers/media/v4l2-core/v4l2-subdev.c >> index 606a909cd778..6cd353d83dfc 100644 >> --- a/drivers/media/v4l2-core/v4l2-subdev.c >> +++ b/drivers/media/v4l2-core/v4l2-subdev.c >> @@ -421,12 +421,8 @@ static int call_s_stream(struct v4l2_subdev *sd, >> int enable) >> * The .s_stream() operation must never be called to start or >> stop an >> * already started or stopped subdev. Catch offenders but don't >> return >> * an error yet to avoid regressions. >> - * >> - * As .s_stream() is mutually exclusive with the >> .enable_streams() and >> - * .disable_streams() operation, we can use the enabled_streams >> field >> - * to store the subdev streaming state. >> */ >> - if (WARN_ON(!!sd->enabled_streams == !!enable)) >> + if (WARN_ON(sd->streaming_enabled == !!enable)) >> return 0; >> ret = sd->ops->video->s_stream(sd, enable); >> @@ -437,7 +433,7 @@ static int call_s_stream(struct v4l2_subdev *sd, >> int enable) >> } >> if (!ret) { >> - sd->enabled_streams = enable ? BIT(0) : 0; >> + sd->streaming_enabled = enable; >> if (enable) >> v4l2_subdev_enable_privacy_led(sd); >> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h >> index a9e6b8146279..f55d03e0acc1 100644 >> --- a/include/media/v4l2-subdev.h >> +++ b/include/media/v4l2-subdev.h >> @@ -1043,6 +1043,8 @@ struct v4l2_subdev_platform_data { >> * v4l2_subdev_enable_streams() and >> * v4l2_subdev_disable_streams() helper functions for >> fallback >> * cases. >> + * @streaming_enabled: Tracks whether streaming has been enabled with >> s_stream. >> + * This is only for call_s_stream() internal use. >> * >> * Each instance of a subdev driver should create this struct, either >> * stand-alone or embedded in a larger struct. >> @@ -1091,6 +1093,7 @@ struct v4l2_subdev { >> */ >> struct v4l2_subdev_state *active_state; >> u64 enabled_streams; >> + bool streaming_enabled; >> }; >> >
Hi Tomi, Thank you for the patch. On Wed, Apr 10, 2024 at 03:35:51PM +0300, Tomi Valkeinen wrote: > call_s_stream() uses sd->enabled_streams to track whether streaming has > already been enabled. However, > v4l2_subdev_enable/disable_streams_fallback(), which was the original > user of this field, already uses it, and > v4l2_subdev_enable/disable_streams_fallback() will call call_s_stream(). > > This leads to a conflict as both functions set the field. Afaics, both > functions set the field to the same value, so it won't cause a runtime > bug, but it's still wrong and if we, e.g., change how > v4l2_subdev_enable/disable_streams_fallback() operates we might easily > cause bugs. > > Fix this by adding a new field, 'streaming_enabled', for > call_s_stream(). > > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > --- > drivers/media/v4l2-core/v4l2-subdev.c | 8 ++------ > include/media/v4l2-subdev.h | 3 +++ > 2 files changed, 5 insertions(+), 6 deletions(-) > > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c > index 606a909cd778..6cd353d83dfc 100644 > --- a/drivers/media/v4l2-core/v4l2-subdev.c > +++ b/drivers/media/v4l2-core/v4l2-subdev.c > @@ -421,12 +421,8 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable) > * The .s_stream() operation must never be called to start or stop an > * already started or stopped subdev. Catch offenders but don't return > * an error yet to avoid regressions. > - * > - * As .s_stream() is mutually exclusive with the .enable_streams() and > - * .disable_streams() operation, we can use the enabled_streams field > - * to store the subdev streaming state. > */ > - if (WARN_ON(!!sd->enabled_streams == !!enable)) > + if (WARN_ON(sd->streaming_enabled == !!enable)) > return 0; > > ret = sd->ops->video->s_stream(sd, enable); > @@ -437,7 +433,7 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable) > } > > if (!ret) { > - sd->enabled_streams = enable ? BIT(0) : 0; > + sd->streaming_enabled = enable; > > if (enable) > v4l2_subdev_enable_privacy_led(sd); > diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h > index a9e6b8146279..f55d03e0acc1 100644 > --- a/include/media/v4l2-subdev.h > +++ b/include/media/v4l2-subdev.h > @@ -1043,6 +1043,8 @@ struct v4l2_subdev_platform_data { > * v4l2_subdev_enable_streams() and > * v4l2_subdev_disable_streams() helper functions for fallback > * cases. > + * @streaming_enabled: Tracks whether streaming has been enabled with s_stream. > + * This is only for call_s_stream() internal use. > * > * Each instance of a subdev driver should create this struct, either > * stand-alone or embedded in a larger struct. > @@ -1091,6 +1093,7 @@ struct v4l2_subdev { > */ > struct v4l2_subdev_state *active_state; > u64 enabled_streams; > + bool streaming_enabled; > }; > >
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 606a909cd778..6cd353d83dfc 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -421,12 +421,8 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable) * The .s_stream() operation must never be called to start or stop an * already started or stopped subdev. Catch offenders but don't return * an error yet to avoid regressions. - * - * As .s_stream() is mutually exclusive with the .enable_streams() and - * .disable_streams() operation, we can use the enabled_streams field - * to store the subdev streaming state. */ - if (WARN_ON(!!sd->enabled_streams == !!enable)) + if (WARN_ON(sd->streaming_enabled == !!enable)) return 0; ret = sd->ops->video->s_stream(sd, enable); @@ -437,7 +433,7 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable) } if (!ret) { - sd->enabled_streams = enable ? BIT(0) : 0; + sd->streaming_enabled = enable; if (enable) v4l2_subdev_enable_privacy_led(sd); diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index a9e6b8146279..f55d03e0acc1 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -1043,6 +1043,8 @@ struct v4l2_subdev_platform_data { * v4l2_subdev_enable_streams() and * v4l2_subdev_disable_streams() helper functions for fallback * cases. + * @streaming_enabled: Tracks whether streaming has been enabled with s_stream. + * This is only for call_s_stream() internal use. * * Each instance of a subdev driver should create this struct, either * stand-alone or embedded in a larger struct. @@ -1091,6 +1093,7 @@ struct v4l2_subdev { */ struct v4l2_subdev_state *active_state; u64 enabled_streams; + bool streaming_enabled; };
call_s_stream() uses sd->enabled_streams to track whether streaming has already been enabled. However, v4l2_subdev_enable/disable_streams_fallback(), which was the original user of this field, already uses it, and v4l2_subdev_enable/disable_streams_fallback() will call call_s_stream(). This leads to a conflict as both functions set the field. Afaics, both functions set the field to the same value, so it won't cause a runtime bug, but it's still wrong and if we, e.g., change how v4l2_subdev_enable/disable_streams_fallback() operates we might easily cause bugs. Fix this by adding a new field, 'streaming_enabled', for call_s_stream(). Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> --- drivers/media/v4l2-core/v4l2-subdev.c | 8 ++------ include/media/v4l2-subdev.h | 3 +++ 2 files changed, 5 insertions(+), 6 deletions(-)