From: Greg KH <gregkh@linuxfoundation.org> To: Wesley Cheng <quic_wcheng@quicinc.com> Cc: srinivas.kandagatla@linaro.org, mathias.nyman@intel.com, perex@perex.cz, broonie@kernel.org, lgirdwood@gmail.com, andersson@kernel.org, krzysztof.kozlowski+dt@linaro.org, Thinh.Nguyen@synopsys.com, bgoswami@quicinc.com, tiwai@suse.com, robh+dt@kernel.org, agross@kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-usb@vger.kernel.org, quic_jackp@quicinc.com, quic_plai@quicinc.com Subject: Re: [RFC PATCH 10/14] sound: usb: card: Check for support for requested audio format Date: Sat, 24 Dec 2022 09:59:01 +0100 [thread overview] Message-ID: <Y6a/VWOg4mBMtUOr@kroah.com> (raw) In-Reply-To: <20221223233200.26089-11-quic_wcheng@quicinc.com> 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
WARNING: multiple messages have this Message-ID (diff)
From: Greg KH <gregkh@linuxfoundation.org> To: Wesley Cheng <quic_wcheng@quicinc.com> Cc: devicetree@vger.kernel.org, alsa-devel@alsa-project.org, linux-usb@vger.kernel.org, bgoswami@quicinc.com, mathias.nyman@intel.com, Thinh.Nguyen@synopsys.com, andersson@kernel.org, tiwai@suse.com, lgirdwood@gmail.com, robh+dt@kernel.org, broonie@kernel.org, srinivas.kandagatla@linaro.org, agross@kernel.org, krzysztof.kozlowski+dt@linaro.org, linux-arm-msm@vger.kernel.org, quic_plai@quicinc.com, linux-kernel@vger.kernel.org, quic_jackp@quicinc.com Subject: Re: [RFC PATCH 10/14] sound: usb: card: Check for support for requested audio format Date: Sat, 24 Dec 2022 09:59:01 +0100 [thread overview] Message-ID: <Y6a/VWOg4mBMtUOr@kroah.com> (raw) In-Reply-To: <20221223233200.26089-11-quic_wcheng@quicinc.com> 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
next prev parent reply other threads:[~2022-12-24 8:59 UTC|newest] Thread overview: 171+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-12-23 23:31 [RFC PATCH 00/14] Introduce QC USB SND audio offloading support Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 01/14] ASoC: Add SOC USB APIs for adding an USB backend Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 6:48 ` Greg KH 2022-12-24 6:48 ` Greg KH 2022-12-23 23:31 ` [RFC PATCH 02/14] ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 1:37 ` kernel test robot 2023-01-04 23:33 ` Pierre-Louis Bossart 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 16:09 ` Pierre-Louis Bossart 2023-01-07 0:51 ` Wesley Cheng 2023-01-07 0:51 ` Wesley Cheng 2023-01-05 18:09 ` Krzysztof Kozlowski 2023-01-05 18:09 ` Krzysztof Kozlowski 2023-01-06 1:32 ` Wesley Cheng 2023-01-06 1:32 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 03/14] ASoC: qcom: Add USB backend ASoC driver for Q6 Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 2:17 ` kernel test robot 2022-12-24 2:17 ` kernel test robot 2022-12-24 9:02 ` Greg KH 2022-12-24 9:02 ` Greg KH 2022-12-27 13:04 ` Mark Brown 2022-12-27 13:04 ` Mark Brown 2022-12-27 13:45 ` Greg KH 2022-12-27 13:45 ` Greg KH 2022-12-27 14:02 ` Takashi Iwai 2022-12-27 14:02 ` Takashi Iwai 2022-12-27 14:11 ` Mark Brown 2022-12-27 14:11 ` Mark Brown 2022-12-27 15:11 ` Mark Brown 2022-12-27 15:11 ` Mark Brown 2022-12-27 21:06 ` Wesley Cheng 2022-12-27 21:06 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2023-01-04 23:41 ` Pierre-Louis Bossart 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 16:16 ` Pierre-Louis Bossart 2022-12-23 23:31 ` [RFC PATCH 04/14] sound: usb: card: Introduce USB SND vendor op callbacks Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 11:03 ` Dmitry Baryshkov 2022-12-24 11:03 ` Dmitry Baryshkov 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:33 ` Dmitry Baryshkov 2022-12-27 21:33 ` Dmitry Baryshkov 2022-12-29 13:49 ` Oliver Neukum 2022-12-29 13:49 ` Oliver Neukum 2022-12-29 14:20 ` Takashi Iwai 2022-12-29 14:20 ` Takashi Iwai 2022-12-30 7:10 ` Wesley Cheng 2022-12-30 7:10 ` Wesley Cheng 2023-01-03 12:20 ` Oliver Neukum 2023-01-03 12:20 ` Oliver Neukum 2023-01-03 12:49 ` Takashi Iwai 2023-01-03 12:49 ` Takashi Iwai 2023-01-03 23:45 ` Wesley Cheng 2023-01-03 23:45 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 05/14] sound: usb: Export USB SND APIs for modules Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 6:48 ` Greg KH 2022-12-24 6:48 ` Greg KH 2022-12-23 23:31 ` [RFC PATCH 06/14] usb: core: hcd: Introduce USB HCD APIs for interrupter management Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 8:54 ` Greg KH 2022-12-24 8:54 ` Greg KH 2022-12-27 21:13 ` Wesley Cheng 2022-12-27 21:13 ` Wesley Cheng 2022-12-24 15:29 ` Alan Stern 2022-12-24 15:29 ` Alan Stern 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2022-12-28 8:59 ` Oliver Neukum 2022-12-28 8:59 ` Oliver Neukum 2022-12-28 15:16 ` Alan Stern 2022-12-28 15:16 ` Alan Stern 2022-12-28 20:31 ` Wesley Cheng 2022-12-28 20:31 ` Wesley Cheng 2022-12-29 1:41 ` Alan Stern 2022-12-29 1:41 ` Alan Stern 2022-12-23 23:31 ` [RFC PATCH 07/14] usb: host: xhci: Add XHCI secondary interrupter support Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 5:59 ` kernel test robot 2022-12-24 8:55 ` Greg KH 2022-12-24 8:55 ` Greg KH 2022-12-28 15:47 ` Mathias Nyman 2022-12-28 15:47 ` Mathias Nyman 2022-12-29 21:14 ` Wesley Cheng 2022-12-29 21:14 ` Wesley Cheng 2023-01-02 16:38 ` Mathias Nyman 2023-01-02 16:38 ` Mathias Nyman 2023-01-09 20:24 ` Wesley Cheng 2023-01-09 20:24 ` Wesley Cheng 2023-01-10 19:47 ` Mathias Nyman 2023-01-10 19:47 ` Mathias Nyman 2023-01-10 20:03 ` Wesley Cheng 2023-01-10 20:03 ` Wesley Cheng 2023-01-11 3:11 ` Wesley Cheng 2023-01-11 3:11 ` Wesley Cheng 2023-01-12 9:24 ` Mathias Nyman 2023-01-12 9:24 ` Mathias Nyman 2023-01-13 0:34 ` Wesley Cheng 2023-01-13 0:34 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 08/14] usb: dwc3: Add DT parameter to specify maximum number of interrupters Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 11:13 ` Dmitry Baryshkov 2022-12-24 11:13 ` Dmitry Baryshkov 2022-12-26 12:28 ` Krzysztof Kozlowski 2022-12-26 12:28 ` Krzysztof Kozlowski 2022-12-27 21:06 ` Wesley Cheng 2022-12-27 21:06 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 09/14] sound: usb: Introduce QC USB SND offloading support Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 2:27 ` kernel test robot 2023-01-02 17:28 ` Takashi Iwai 2023-01-02 17:28 ` Takashi Iwai 2023-01-04 22:38 ` Wesley Cheng 2023-01-04 22:38 ` Wesley Cheng 2023-01-04 23:51 ` Pierre-Louis Bossart 2023-01-06 1:06 ` Wesley Cheng 2023-01-06 1:06 ` Wesley Cheng 2022-12-23 23:31 ` [RFC PATCH 10/14] sound: usb: card: Check for support for requested audio format Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 8:59 ` Greg KH [this message] 2022-12-24 8:59 ` Greg KH 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 21:07 ` Wesley Cheng 2022-12-27 20:31 ` kernel test robot 2022-12-23 23:31 ` [RFC PATCH 11/14] sound: soc: soc-usb: Add PCM format check API for USB backend Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 2:17 ` kernel test robot 2022-12-24 2:17 ` kernel test robot 2022-12-23 23:31 ` [RFC PATCH 12/14] sound: soc: qcom: qusb6: Ensure PCM format is supported by USB audio device Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-24 8:19 ` Sergey Shtylyov 2022-12-24 8:19 ` Sergey Shtylyov 2022-12-24 8:50 ` Wesley Cheng 2022-12-24 8:50 ` Wesley Cheng 2023-01-03 17:44 ` Mark Brown 2023-01-03 17:44 ` Mark Brown 2022-12-23 23:31 ` [RFC PATCH 13/14] ASoC: dt-bindings: Add Q6USB backend bindings Wesley Cheng 2022-12-23 23:31 ` Wesley Cheng 2022-12-26 12:25 ` Krzysztof Kozlowski 2022-12-26 12:25 ` Krzysztof Kozlowski 2022-12-23 23:32 ` [RFC PATCH 14/14] ASoC: dt-bindings: Update example for enabling USB offload on SM8250 Wesley Cheng 2022-12-23 23:32 ` Wesley Cheng 2022-12-26 12:27 ` Krzysztof Kozlowski 2022-12-26 12:27 ` Krzysztof Kozlowski 2023-01-03 17:46 ` Mark Brown 2023-01-03 17:46 ` Mark Brown 2023-01-05 18:09 ` Krzysztof Kozlowski 2023-01-05 18:09 ` Krzysztof Kozlowski 2023-01-04 0:46 ` Rob Herring 2023-01-04 0:46 ` Rob Herring 2022-12-24 6:45 ` [RFC PATCH 00/14] Introduce QC USB SND audio offloading support Greg KH 2022-12-24 6:45 ` Greg KH 2022-12-24 8:49 ` Wesley Cheng 2022-12-24 8:49 ` Wesley Cheng 2022-12-27 14:36 ` Mark Brown 2022-12-27 14:36 ` Mark Brown 2023-01-04 23:19 ` Pierre-Louis Bossart 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 1:05 ` Wesley Cheng 2023-01-06 15:57 ` Pierre-Louis Bossart 2023-01-07 0:46 ` Wesley Cheng 2023-01-07 0:46 ` Wesley Cheng
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