At Thu, 11 Jul 2013 22:13:35 +0800, Ming Lei wrote: > > On Thu, Jul 11, 2013 at 9:50 PM, Takashi Iwai <tiwai@xxxxxxx> wrote: > > At Thu, 11 Jul 2013 17:08:30 +0400, > > Sergei Shtylyov wrote: > >> > >> On 11-07-2013 13:06, Ming Lei wrote: > >> > >> > Complete() will be run with interrupt enabled, so change to > >> > spin_lock_irqsave(). > >> > >> Changelog doesn't match the patch. > > > > Yep, but moreover... > > > >> > Cc: Jaroslav Kysela <perex@xxxxxxxx> > >> > Cc: Takashi Iwai <tiwai@xxxxxxx> > >> > Cc: alsa-devel@xxxxxxxxxxxxxxxx > >> > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx> > >> > --- > >> > sound/usb/usx2y/usbusx2yaudio.c | 4 ++++ > >> > 1 file changed, 4 insertions(+) > >> > >> > diff --git a/sound/usb/usx2y/usbusx2yaudio.c b/sound/usb/usx2y/usbusx2yaudio.c > >> > index 4967fe9..e2ee893 100644 > >> > --- a/sound/usb/usx2y/usbusx2yaudio.c > >> > +++ b/sound/usb/usx2y/usbusx2yaudio.c > >> > @@ -273,7 +273,11 @@ static void usX2Y_clients_stop(struct usX2Ydev *usX2Y) > >> > struct snd_usX2Y_substream *subs = usX2Y->subs[s]; > >> > if (subs) { > >> > if (atomic_read(&subs->state) >= state_PRERUNNING) { > >> > + unsigned long flags; > >> > + > >> > + local_irq_save(flags); > >> > snd_pcm_stop(subs->pcm_substream, SNDRV_PCM_STATE_XRUN); > >> > + local_irq_restore(flags); > >> > } > > > > ... actually this snd_pcm_stop() call should have been covered by > > snd_pcm_stream_lock(). Maybe it'd be enough to have a single patch > > together with the change, i.e. wrapping with > > snd_pcm_stream_lock_irqsave(). > > Please use snd_pcm_stream_lock_irqsave() so that I can avoid sending > out similar patch later, :-) > > > > > I'll prepare the patch for 3.11 independently from your patch series, > > so please drop this one. > > OK, thanks for dealing with that. > > > > > > > BTW, the word "cleanup" in the subject is inappropriate. This is > > rather a fix together with the core change. > > It is a cleanup since the patchset only addresses lock problem which > is caused by the tasklet conversion. Well, the conversion to irqsave() is needed for the future drop of irq_save() in the caller, right? Then this isn't a cleanup but a preparation for movement ahead. > > And, I wonder whether we can take a safer approach. When the caller > > condition changed, we often introduced either a different ops > > (e.g. ioctl case) or a flag for the new condition, at least during the > > transition period. > > Interrupt is't enabled until all current drivers are cleaned up, so it is really > safe, please see patch [2]. OK. > > Last but not least, is a conversion to tasklet really preferred? > > tasklet is rather an obsoleted infrastructure nowadays, and people > > don't recommend to use it any longer, AFAIK. > > We discussed the problem in the below link previously[1], Steven > and Thomas suggested to use threaded irq handler, but which > may degrade USB mass storage performance, so we have to > take tasklet now until we rewrite transport part of USB mass storage > driver. > > Also the conversion[2] has avoided the tasklet spin lock problem > already. OK, good to know. thanks, Takashi > [1], http://marc.info/?t=137079119200001&r=1&w=2 > [2], http://marc.info/?l=linux-usb&m=137286326726326&w=2 > > Thanks, > -- > Ming Lei > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html