| Message ID | 20221223233200.26089-11-quic_wcheng@quicinc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Introduce QC USB SND audio offloading support | expand |
On Fri, Dec 23, 2022 at 03:31:56PM -0800, Wesley Cheng wrote: > Allow for checks on a specific USB audio device to see if a requested PCM > format is supported. This is needed for support for when playback is > initiated by the ASoC USB backend path. > > Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> > --- > sound/usb/card.c | 19 +++++++++++++++++++ > sound/usb/card.h | 3 +++ > 2 files changed, 22 insertions(+) > > diff --git a/sound/usb/card.c b/sound/usb/card.c > index 396e5a34e23b..9b8d2ed308c8 100644 > --- a/sound/usb/card.c > +++ b/sound/usb/card.c > @@ -133,6 +133,25 @@ int snd_usb_unregister_vendor_ops(void) > } > EXPORT_SYMBOL_GPL(snd_usb_unregister_vendor_ops); > > +struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, > + struct snd_pcm_hw_params *params, int direction) > +{ > + struct snd_usb_stream *as; > + struct snd_usb_substream *subs = NULL; > + const struct audioformat *fmt; > + > + if (usb_chip[card_idx] && enable[card_idx]) { > + list_for_each_entry(as, &usb_chip[card_idx]->pcm_list, list) { > + subs = &as->substream[direction]; > + fmt = find_substream_format(subs, params); > + if (fmt) > + return as; > + } > + } Where is the locking here? How can you walk a list that can be changed as you walk it? And what about reference counting? You are returning a pointer to a structure, who now "owns" it? What happens if it is removed from the system after you return it? > + return 0; Didn't sparse complain about this? You can't return "0" as a pointer, it should be NULL. Always run basic tools like sparse on code before submitting it so that we don't have to find errors like this. thanks, greg k-h
Hi Greg, On 12/24/2022 12:59 AM, Greg KH wrote: > On Fri, Dec 23, 2022 at 03:31:56PM -0800, Wesley Cheng wrote: >> Allow for checks on a specific USB audio device to see if a requested PCM >> format is supported. This is needed for support for when playback is >> initiated by the ASoC USB backend path. >> >> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> >> --- >> sound/usb/card.c | 19 +++++++++++++++++++ >> sound/usb/card.h | 3 +++ >> 2 files changed, 22 insertions(+) >> >> diff --git a/sound/usb/card.c b/sound/usb/card.c >> index 396e5a34e23b..9b8d2ed308c8 100644 >> --- a/sound/usb/card.c >> +++ b/sound/usb/card.c >> @@ -133,6 +133,25 @@ int snd_usb_unregister_vendor_ops(void) >> } >> EXPORT_SYMBOL_GPL(snd_usb_unregister_vendor_ops); >> >> +struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, >> + struct snd_pcm_hw_params *params, int direction) >> +{ >> + struct snd_usb_stream *as; >> + struct snd_usb_substream *subs = NULL; >> + const struct audioformat *fmt; >> + >> + if (usb_chip[card_idx] && enable[card_idx]) { >> + list_for_each_entry(as, &usb_chip[card_idx]->pcm_list, list) { >> + subs = &as->substream[direction]; >> + fmt = find_substream_format(subs, params); >> + if (fmt) >> + return as; >> + } >> + } > > Where is the locking here? How can you walk a list that can be changed > as you walk it? > > And what about reference counting? You are returning a pointer to a > structure, who now "owns" it? What happens if it is removed from the > system after you return it? > >> + return 0; > > Didn't sparse complain about this? You can't return "0" as a pointer, > it should be NULL. > > Always run basic tools like sparse on code before submitting it so that > we don't have to find errors like this. > Got it...I didn't get a chance to run that, but will do it on future submissions. Will also address the locking and pointer reference you mentioned. Thanks Wesley Cheng
diff --git a/sound/usb/card.c b/sound/usb/card.c index 396e5a34e23b..9b8d2ed308c8 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -133,6 +133,25 @@ int snd_usb_unregister_vendor_ops(void) } EXPORT_SYMBOL_GPL(snd_usb_unregister_vendor_ops); +struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, + struct snd_pcm_hw_params *params, int direction) +{ + struct snd_usb_stream *as; + struct snd_usb_substream *subs = NULL; + const struct audioformat *fmt; + + if (usb_chip[card_idx] && enable[card_idx]) { + list_for_each_entry(as, &usb_chip[card_idx]->pcm_list, list) { + subs = &as->substream[direction]; + fmt = find_substream_format(subs, params); + if (fmt) + return as; + } + } + + return 0; +} + /* * disconnect streams * called from usb_audio_disconnect() diff --git a/sound/usb/card.h b/sound/usb/card.h index a785bb256b0d..d4936b6054fc 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -213,4 +213,7 @@ struct snd_usb_vendor_ops { int snd_usb_register_vendor_ops(struct snd_usb_vendor_ops *ops); int snd_usb_unregister_vendor_ops(void); + +struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, + struct snd_pcm_hw_params *params, int direction); #endif /* __USBAUDIO_CARD_H */
Allow for checks on a specific USB audio device to see if a requested PCM format is supported. This is needed for support for when playback is initiated by the ASoC USB backend path. Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com> --- sound/usb/card.c | 19 +++++++++++++++++++ sound/usb/card.h | 3 +++ 2 files changed, 22 insertions(+)