From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Cezary Rojewski <cezary.rojewski@intel.com>
Cc: pierre-louis.bossart@linux.intel.com,
alsa-devel@alsa-project.org, filip.kaczmarski@intel.com,
harshapriya.n@intel.com, marcin.barlik@intel.com,
zwisler@google.com, lgirdwood@gmail.com, tiwai@suse.com,
filip.proborszcz@intel.com, broonie@kernel.org,
amadeuszx.slawinski@linux.intel.com, michal.wasko@intel.com,
cujomalainey@chromium.org, krzysztof.hejmowski@intel.com,
ppapierkowski@habana.ai, vamshi.krishna.gopal@intel.com
Subject: Re: [PATCH v4 02/13] ASoC: Intel: catpt: Define DSP operations
Date: Wed, 19 Aug 2020 17:21:28 +0300 [thread overview]
Message-ID: <20200819142128.GP1891694@smile.fi.intel.com> (raw)
In-Reply-To: <9a733e30-8d44-edf7-1bae-5b6f935628d2@intel.com>
On Wed, Aug 19, 2020 at 03:46:30PM +0200, Cezary Rojewski wrote:
> On 2020-08-18 1:50 PM, Andy Shevchenko wrote:
> > On Mon, Aug 17, 2020 at 01:12:01PM +0200, Cezary Rojewski wrote:
> > > On 2020-08-13 8:51 PM, Andy Shevchenko wrote:
> > > > On Wed, Aug 12, 2020 at 10:57:42PM +0200, Cezary Rojewski wrote:
...
> > > > > + bool lp;
> > > > > +
> > > > > + if (list_empty(&cdev->stream_list))
> > > > > + return catpt_dsp_select_lpclock(cdev, true, true);
> > > > > +
> > > > > + lp = true;
> > > > > + list_for_each_entry(stream, &cdev->stream_list, node) {
> > > > > + if (stream->prepared) {
> > > > > + lp = false;
> > > > > + break;
> > > > > + }
> > > > > + }
> > > > > +
> > > > > + return catpt_dsp_select_lpclock(cdev, lp, true);
> > > >
> > > > Seems too much duplication.
> > > >
> > > > struct catpt_stream_runtime *stream;
> > > >
> > > > list_for_each_entry(stream, &cdev->stream_list, node) {
> > > > if (stream->prepared)
> > > > return catpt_dsp_select_lpclock(cdev, false, true);
> > > > }
> > > >
> > > > return catpt_dsp_select_lpclock(cdev, true, true);
> > > >
> > > >
> > > > Better?
> > >
> > > list_first_entry (part of list_for_each_entry) expects list to be non-empty.
> > > ->streal_list may be empty when invoking catpt_dsp_update_lpclock().
> >
> > I didn't get this. Can you point out where is exactly problematic place?
> >
>
> list_for_each_entry makes use of list_first_entry when initializing 'pos'
> index variable.
Correct.
> Documentation for list_first_entry reads: "Note, that list
> is expected to be not empty"
Correct.
> so I'm validating list's status before moving
> on to the loop as stream_list may be empty when catpt_dsp_update_lpclock()
> gets called.
But here you missed the second part of the for-loop, i.e. exit conditional.
If your assumption (that list_for_each_*() is not empty-safe) is correct,
it would be disaster in global kernel source level.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2020-08-19 14:22 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-12 20:57 [PATCH v4 00/13] ASoC: Intel: Catpt - Lynx and Wildcat point Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 01/13] ASoC: Intel: Add catpt device Cezary Rojewski
2020-08-13 18:29 ` Andy Shevchenko
2020-08-17 10:02 ` Cezary Rojewski
2020-08-18 10:07 ` Andy Shevchenko
2020-08-19 13:26 ` Cezary Rojewski
2020-08-19 13:43 ` Andy Shevchenko
2020-08-25 9:32 ` Cezary Rojewski
2020-08-25 13:18 ` Andy Shevchenko
2020-08-25 13:19 ` Andy Shevchenko
2020-08-25 20:43 ` Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 02/13] ASoC: Intel: catpt: Define DSP operations Cezary Rojewski
2020-08-13 18:51 ` Andy Shevchenko
2020-08-17 11:12 ` Cezary Rojewski
2020-08-18 11:50 ` Andy Shevchenko
2020-08-19 13:46 ` Cezary Rojewski
2020-08-19 14:21 ` Andy Shevchenko [this message]
2020-08-19 14:54 ` Cezary Rojewski
2020-08-20 7:30 ` Cezary Rojewski
2020-08-20 9:00 ` Andy Shevchenko
2020-08-24 16:33 ` Cezary Rojewski
2020-08-25 13:16 ` Andy Shevchenko
2020-08-25 13:23 ` Andy Shevchenko
2020-08-27 10:06 ` Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 03/13] ASoC: Intel: catpt: Firmware loading and context restore Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 04/13] ASoC: Intel: catpt: Implement IPC protocol Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 05/13] ASoC: Intel: catpt: Add IPC messages Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 06/13] ASoC: Intel: catpt: PCM operations Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 07/13] ASoC: Intel: catpt: Event tracing Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 08/13] ASoC: Intel: catpt: Simple sysfs attributes Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 09/13] ASoC: Intel: Select catpt and deprecate haswell Cezary Rojewski
2020-08-12 20:57 ` [PATCH v4 10/13] ASoC: Intel: haswell: Remove haswell-solution specific code Cezary Rojewski
2020-08-13 18:57 ` Andy Shevchenko
2020-08-12 20:57 ` [PATCH v4 11/13] ASoC: Intel: broadwell: " Cezary Rojewski
2020-08-13 18:56 ` Andy Shevchenko
2020-08-12 20:57 ` [PATCH v4 12/13] ASoC: Intel: bdw-5650: " Cezary Rojewski
2020-08-13 18:56 ` Andy Shevchenko
2020-08-12 20:57 ` [PATCH v4 13/13] ASoC: Intel: bdw-5677: " Cezary Rojewski
2020-08-13 18:57 ` Andy Shevchenko
2020-08-13 8:30 ` [PATCH v4 00/13] ASoC: Intel: Catpt - Lynx and Wildcat point Amadeusz Sławiński
2020-08-13 16:00 ` Liam Girdwood
2020-08-13 18:11 ` Cezary Rojewski
2020-08-13 19:03 ` Liam Girdwood
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