diff mbox series

[RFC,v3,04/13] ASoC: soc-pcm: introduce snd_soc_dpcm_fe_lock_irq/unlock_irq()

Message ID 20211013143050.244444-5-pierre-louis.bossart@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series ASoC : soc-pcm: fix trigger race conditions with shared BE | expand

Commit Message

Pierre-Louis Bossart Oct. 13, 2021, 2:30 p.m. UTC 
In preparation for more changes, add two new helpers to gradually
modify the DPCM locks.

Since DPCM functions are not used from interrupt handlers, we can only
use the lock_irq case.

While most of the uses of DPCM are internal to soc-pcm.c, some drivers
in soc/fsl and soc/sh do make use of DPCM-related loops that will
require protection, adding EXPORT_SYMBOL_GPL() is needed for those
drivers.

The stream argument is unused in this patch but will be enabled in
follow-up patches.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 include/sound/soc-dpcm.h |  3 +++
 sound/soc/soc-pcm.c      | 42 +++++++++++++++++++++++-----------------
 2 files changed, 27 insertions(+), 18 deletions(-)

Comments

Sameer Pujar Oct. 15, 2021, 6:24 a.m. UTC | #1 
On 10/13/2021 8:00 PM, Pierre-Louis Bossart wrote:
> In preparation for more changes, add two new helpers to gradually
> modify the DPCM locks.
>
> Since DPCM functions are not used from interrupt handlers, we can only
> use the lock_irq case.
>
> While most of the uses of DPCM are internal to soc-pcm.c, some drivers
> in soc/fsl and soc/sh do make use of DPCM-related loops that will
> require protection, adding EXPORT_SYMBOL_GPL() is needed for those
> drivers.
>
> The stream argument is unused in this patch but will be enabled in
> follow-up patches.
>
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> ---
>   include/sound/soc-dpcm.h |  3 +++
>   sound/soc/soc-pcm.c      | 42 +++++++++++++++++++++++-----------------
>   2 files changed, 27 insertions(+), 18 deletions(-)

1. Till this patch and with DEBUG_LOCKDEP config enabled, I see 
following warning:
    "WARNING: CPU: 0 PID: 0 at kernel/locking/irqflag-debug.c:10 
warn_bogus_irq_restore+0x30/0x40"

    However test passed though. Interestingly it was seen only for the 
first time I ran a 2x1 mixer test.

2. Also after I load sound modules and card gets registered, I see some 
hw_param() calls for FE and BE. This seems harmless at this point, but 
is getting problematic with subsequent patches. This was not happening 
earier.
Pierre-Louis Bossart Oct. 15, 2021, 12:24 p.m. UTC | #2 
On 10/15/21 1:24 AM, Sameer Pujar wrote:
> 
> 
> On 10/13/2021 8:00 PM, Pierre-Louis Bossart wrote:
>> In preparation for more changes, add two new helpers to gradually
>> modify the DPCM locks.
>>
>> Since DPCM functions are not used from interrupt handlers, we can only
>> use the lock_irq case.
>>
>> While most of the uses of DPCM are internal to soc-pcm.c, some drivers
>> in soc/fsl and soc/sh do make use of DPCM-related loops that will
>> require protection, adding EXPORT_SYMBOL_GPL() is needed for those
>> drivers.
>>
>> The stream argument is unused in this patch but will be enabled in
>> follow-up patches.
>>
>> Signed-off-by: Pierre-Louis Bossart
>> <pierre-louis.bossart@linux.intel.com>
>> ---
>>   include/sound/soc-dpcm.h |  3 +++
>>   sound/soc/soc-pcm.c      | 42 +++++++++++++++++++++++-----------------
>>   2 files changed, 27 insertions(+), 18 deletions(-)
> 
> 1. Till this patch and with DEBUG_LOCKDEP config enabled, I see

Did you mean "with this patch included", yes?

> following warning:
>    "WARNING: CPU: 0 PID: 0 at kernel/locking/irqflag-debug.c:10
> warn_bogus_irq_restore+0x30/0x40"
> 
>    However test passed though. Interestingly it was seen only for the
> first time I ran a 2x1 mixer test.
> 
> 2. Also after I load sound modules and card gets registered, I see some
> hw_param() calls for FE and BE. This seems harmless at this point, but
> is getting problematic with subsequent patches. This was not happening
> earier.

This patch doesn't change any of the flow, it just adds a wrapper in
preparation for the transition to the FE pcm lock.

The only change is that we use spin_lock_irq instead of the
irqsave/restore version, but that was also Takashi's recommendation.

the test results would suggest that on Tegra DPCM functions are used
from an interrupt context?
diff mbox series

Patch

diff --git a/include/sound/soc-dpcm.h b/include/sound/soc-dpcm.h
index 9c00118603e7..8ed40b8f3da8 100644
--- a/include/sound/soc-dpcm.h
+++ b/include/sound/soc-dpcm.h
@@ -151,4 +151,7 @@  bool dpcm_end_walk_at_be(struct snd_soc_dapm_widget *widget, enum snd_soc_dapm_d
 #define dpcm_be_dai_startup_unwind(fe, stream)	dpcm_be_dai_stop(fe, stream, 0, NULL)
 #define dpcm_be_dai_shutdown(fe, stream)	dpcm_be_dai_stop(fe, stream, 1, NULL)
 
+void snd_soc_dpcm_fe_lock_irq(struct snd_soc_pcm_runtime *fe, int stream);
+void snd_soc_dpcm_fe_unlock_irq(struct snd_soc_pcm_runtime *fe, int stream);
+
 #endif
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 19539300d94d..52851827d53f 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -29,6 +29,18 @@ 
 
 #define DPCM_MAX_BE_USERS	8
 
+void snd_soc_dpcm_fe_lock_irq(struct snd_soc_pcm_runtime *fe, int stream)
+{
+	spin_lock_irq(&fe->card->dpcm_lock);
+}
+EXPORT_SYMBOL_GPL(snd_soc_dpcm_fe_lock_irq);
+
+void snd_soc_dpcm_fe_unlock_irq(struct snd_soc_pcm_runtime *fe, int stream)
+{
+	spin_unlock_irq(&fe->card->dpcm_lock);
+}
+EXPORT_SYMBOL_GPL(snd_soc_dpcm_fe_unlock_irq);
+
 /* can this BE stop and free */
 static int snd_soc_dpcm_can_be_free_stop(struct snd_soc_pcm_runtime *fe,
 					 struct snd_soc_pcm_runtime *be, int stream);
@@ -85,7 +97,6 @@  static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 	struct snd_pcm_hw_params *params = &fe->dpcm[stream].hw_params;
 	struct snd_soc_dpcm *dpcm;
 	ssize_t offset = 0;
-	unsigned long flags;
 
 	/* FE state */
 	offset += scnprintf(buf + offset, size - offset,
@@ -113,7 +124,7 @@  static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 		goto out;
 	}
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	for_each_dpcm_be(fe, stream, dpcm) {
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 		params = &dpcm->hw_params;
@@ -134,7 +145,7 @@  static ssize_t dpcm_show_state(struct snd_soc_pcm_runtime *fe,
 					   params_channels(params),
 					   params_rate(params));
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 out:
 	return offset;
 }
@@ -1141,7 +1152,6 @@  static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 		struct snd_soc_pcm_runtime *be, int stream)
 {
 	struct snd_soc_dpcm *dpcm;
-	unsigned long flags;
 
 	/* only add new dpcms */
 	for_each_dpcm_be(fe, stream, dpcm) {
@@ -1157,10 +1167,10 @@  static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 	dpcm->fe = fe;
 	be->dpcm[stream].runtime = fe->dpcm[stream].runtime;
 	dpcm->state = SND_SOC_DPCM_LINK_STATE_NEW;
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	list_add(&dpcm->list_be, &fe->dpcm[stream].be_clients);
 	list_add(&dpcm->list_fe, &be->dpcm[stream].fe_clients);
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 
 	dev_dbg(fe->dev, "connected new DPCM %s path %s %s %s\n",
 			stream ? "capture" : "playback",  fe->dai_link->name,
@@ -1203,7 +1213,6 @@  static void dpcm_be_reparent(struct snd_soc_pcm_runtime *fe,
 void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
 {
 	struct snd_soc_dpcm *dpcm, *d;
-	unsigned long flags;
 
 	for_each_dpcm_be_safe(fe, stream, dpcm, d) {
 		dev_dbg(fe->dev, "ASoC: BE %s disconnect check for %s\n",
@@ -1222,10 +1231,10 @@  void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream)
 
 		dpcm_remove_debugfs_state(dpcm);
 
-		spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+		snd_soc_dpcm_fe_lock_irq(fe, stream);
 		list_del(&dpcm->list_be);
 		list_del(&dpcm->list_fe);
-		spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+		snd_soc_dpcm_fe_unlock_irq(fe, stream);
 		kfree(dpcm);
 	}
 }
@@ -1451,12 +1460,11 @@  int dpcm_process_paths(struct snd_soc_pcm_runtime *fe,
 void dpcm_clear_pending_state(struct snd_soc_pcm_runtime *fe, int stream)
 {
 	struct snd_soc_dpcm *dpcm;
-	unsigned long flags;
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	for_each_dpcm_be(fe, stream, dpcm)
 		dpcm_set_be_update_state(dpcm->be, stream, SND_SOC_DPCM_UPDATE_NO);
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 }
 
 void dpcm_be_dai_stop(struct snd_soc_pcm_runtime *fe, int stream,
@@ -2374,7 +2382,6 @@  static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 	struct snd_soc_dpcm *dpcm;
 	enum snd_soc_dpcm_trigger trigger = fe->dai_link->trigger[stream];
 	int ret = 0;
-	unsigned long flags;
 
 	dev_dbg(fe->dev, "ASoC: runtime %s open on FE %s\n",
 			stream ? "capture" : "playback", fe->dai_link->name);
@@ -2443,7 +2450,7 @@  static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 	dpcm_be_dai_shutdown(fe, stream);
 disconnect:
 	/* disconnect any pending BEs */
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	for_each_dpcm_be(fe, stream, dpcm) {
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 
@@ -2455,7 +2462,7 @@  static int dpcm_run_update_startup(struct snd_soc_pcm_runtime *fe, int stream)
 			be->dpcm[stream].state == SND_SOC_DPCM_STATE_NEW)
 				dpcm->state = SND_SOC_DPCM_LINK_STATE_FREE;
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 
 	if (ret < 0)
 		dev_err(fe->dev, "ASoC: %s() failed (%d)\n", __func__, ret);
@@ -2855,10 +2862,9 @@  static int snd_soc_dpcm_check_state(struct snd_soc_pcm_runtime *fe,
 	struct snd_soc_dpcm *dpcm;
 	int state;
 	int ret = 1;
-	unsigned long flags;
 	int i;
 
-	spin_lock_irqsave(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_lock_irq(fe, stream);
 	for_each_dpcm_fe(be, stream, dpcm) {
 
 		if (dpcm->fe == fe)
@@ -2872,7 +2878,7 @@  static int snd_soc_dpcm_check_state(struct snd_soc_pcm_runtime *fe,
 			}
 		}
 	}
-	spin_unlock_irqrestore(&fe->card->dpcm_lock, flags);
+	snd_soc_dpcm_fe_unlock_irq(fe, stream);
 
 	/* it's safe to do this BE DAI */
 	return ret;