ALSA: pcm: Use guard() for PCM stream locks

Define guard() usage for PCM stream locking and use it in appropriate
places.

The pair of snd_pcm_stream_lock() and snd_pcm_stream_unlock() can be
presented with guard(pcm_stream_lock) now.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240227085306.9764-23-tiwai@suse.de

include/sound/pcm.h

@@ -659,6 +659,18 @@ void snd_pcm_stream_unlock_irqrestore(struct snd_pcm_substream *substream,
 		flags = _snd_pcm_stream_lock_irqsave_nested(substream); \
 	} while (0)
 
+/* definitions for guard(); use like guard(pcm_stream_lock) */
+DEFINE_LOCK_GUARD_1(pcm_stream_lock, struct snd_pcm_substream,
+		    snd_pcm_stream_lock(_T->lock),
+		    snd_pcm_stream_unlock(_T->lock))
+DEFINE_LOCK_GUARD_1(pcm_stream_lock_irq, struct snd_pcm_substream,
+		    snd_pcm_stream_lock_irq(_T->lock),
+		    snd_pcm_stream_unlock_irq(_T->lock))
+DEFINE_LOCK_GUARD_1(pcm_stream_lock_irqsave, struct snd_pcm_substream,
+		    snd_pcm_stream_lock_irqsave(_T->lock, _T->flags),
+		    snd_pcm_stream_unlock_irqrestore(_T->lock, _T->flags),
+		    unsigned long flags)
+
 /**
  * snd_pcm_group_for_each_entry - iterate over the linked substreams
  * @s: the iterator

sound/core/oss/pcm_oss.c

@@ -1623,9 +1623,8 @@ static int snd_pcm_oss_sync1(struct snd_pcm_substream *substream, size_t size)
 			break;
 		result = 0;
 		set_current_state(TASK_INTERRUPTIBLE);
-		snd_pcm_stream_lock_irq(substream);
-		state = runtime->state;
-		snd_pcm_stream_unlock_irq(substream);
+		scoped_guard(pcm_stream_lock_irq, substream)
+			state = runtime->state;
 		if (state != SNDRV_PCM_STATE_RUNNING) {
 			set_current_state(TASK_RUNNING);
 			break;
@@ -2840,23 +2839,23 @@ static __poll_t snd_pcm_oss_poll(struct file *file, poll_table * wait)
 	if (psubstream != NULL) {
 		struct snd_pcm_runtime *runtime = psubstream->runtime;
 		poll_wait(file, &runtime->sleep, wait);
-		snd_pcm_stream_lock_irq(psubstream);
-		if (runtime->state != SNDRV_PCM_STATE_DRAINING &&
-		    (runtime->state != SNDRV_PCM_STATE_RUNNING ||
-		     snd_pcm_oss_playback_ready(psubstream)))
-			mask |= EPOLLOUT | EPOLLWRNORM;
-		snd_pcm_stream_unlock_irq(psubstream);
+		scoped_guard(pcm_stream_lock_irq, psubstream) {
+			if (runtime->state != SNDRV_PCM_STATE_DRAINING &&
+			    (runtime->state != SNDRV_PCM_STATE_RUNNING ||
+			     snd_pcm_oss_playback_ready(psubstream)))
+				mask |= EPOLLOUT | EPOLLWRNORM;
+		}
 	}
 	if (csubstream != NULL) {
 		struct snd_pcm_runtime *runtime = csubstream->runtime;
 		snd_pcm_state_t ostate;
 		poll_wait(file, &runtime->sleep, wait);
-		snd_pcm_stream_lock_irq(csubstream);
-		ostate = runtime->state;
-		if (ostate != SNDRV_PCM_STATE_RUNNING ||
-		    snd_pcm_oss_capture_ready(csubstream))
-			mask |= EPOLLIN | EPOLLRDNORM;
-		snd_pcm_stream_unlock_irq(csubstream);
+		scoped_guard(pcm_stream_lock_irq, csubstream) {
+			ostate = runtime->state;
+			if (ostate != SNDRV_PCM_STATE_RUNNING ||
+			    snd_pcm_oss_capture_ready(csubstream))
+				mask |= EPOLLIN | EPOLLRDNORM;
+		}
 		if (ostate != SNDRV_PCM_STATE_RUNNING && runtime->oss.trigger) {
 			struct snd_pcm_oss_file ofile;
 			memset(&ofile, 0, sizeof(ofile));

sound/core/pcm_compat.c

@@ -432,22 +432,22 @@ static int snd_pcm_ioctl_sync_ptr_x32(struct snd_pcm_substream *substream,
 	boundary = recalculate_boundary(runtime);
 	if (!boundary)
 		boundary = 0x7fffffff;
-	snd_pcm_stream_lock_irq(substream);
-	/* FIXME: we should consider the boundary for the sync from app */
-	if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
-		control->appl_ptr = scontrol.appl_ptr;
-	else
-		scontrol.appl_ptr = control->appl_ptr % boundary;
-	if (!(sflags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
-		control->avail_min = scontrol.avail_min;
-	else
-		scontrol.avail_min = control->avail_min;
-	sstatus.state = status->state;
-	sstatus.hw_ptr = status->hw_ptr % boundary;
-	sstatus.tstamp = status->tstamp;
-	sstatus.suspended_state = status->suspended_state;
-	sstatus.audio_tstamp = status->audio_tstamp;
-	snd_pcm_stream_unlock_irq(substream);
+	scoped_guard(pcm_stream_lock_irq, substream) {
+		/* FIXME: we should consider the boundary for the sync from app */
+		if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
+			control->appl_ptr = scontrol.appl_ptr;
+		else
+			scontrol.appl_ptr = control->appl_ptr % boundary;
+		if (!(sflags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
+			control->avail_min = scontrol.avail_min;
+		else
+			scontrol.avail_min = control->avail_min;
+		sstatus.state = status->state;
+		sstatus.hw_ptr = status->hw_ptr % boundary;
+		sstatus.tstamp = status->tstamp;
+		sstatus.suspended_state = status->suspended_state;
+		sstatus.audio_tstamp = status->audio_tstamp;
+	}
 	if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
 		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 	if (put_user(sstatus.state, &src->s.status.state) ||
@@ -510,26 +510,24 @@ static int snd_pcm_ioctl_sync_ptr_buggy(struct snd_pcm_substream *substream,
 		if (err < 0)
 			return err;
 	}
-	snd_pcm_stream_lock_irq(substream);
-	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) {
-		err = pcm_lib_apply_appl_ptr(substream, sync_cp->appl_ptr);
-		if (err < 0) {
-			snd_pcm_stream_unlock_irq(substream);
-			return err;
+	scoped_guard(pcm_stream_lock_irq, substream) {
+		if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) {
+			err = pcm_lib_apply_appl_ptr(substream, sync_cp->appl_ptr);
+			if (err < 0)
+				return err;
+		} else {
+			sync_cp->appl_ptr = control->appl_ptr;
 		}
-	} else {
-		sync_cp->appl_ptr = control->appl_ptr;
+		if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
+			control->avail_min = sync_cp->avail_min;
+		else
+			sync_cp->avail_min = control->avail_min;
+		sync_ptr.s.status.state = status->state;
+		sync_ptr.s.status.hw_ptr = status->hw_ptr;
+		sync_ptr.s.status.tstamp = status->tstamp;
+		sync_ptr.s.status.suspended_state = status->suspended_state;
+		sync_ptr.s.status.audio_tstamp = status->audio_tstamp;
 	}
-	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
-		control->avail_min = sync_cp->avail_min;
-	else
-		sync_cp->avail_min = control->avail_min;
-	sync_ptr.s.status.state = status->state;
-	sync_ptr.s.status.hw_ptr = status->hw_ptr;
-	sync_ptr.s.status.tstamp = status->tstamp;
-	sync_ptr.s.status.suspended_state = status->suspended_state;
-	sync_ptr.s.status.audio_tstamp = status->audio_tstamp;
-	snd_pcm_stream_unlock_irq(substream);
 	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL))
 		snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 	if (copy_to_user(_sync_ptr, &sync_ptr, sizeof(sync_ptr)))

sound/core/pcm_lib.c

@@ -1744,8 +1744,8 @@ static int snd_pcm_lib_ioctl_reset(struct snd_pcm_substream *substream,
 				   void *arg)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
-	unsigned long flags;
-	snd_pcm_stream_lock_irqsave(substream, flags);
+
+	guard(pcm_stream_lock_irqsave)(substream);
 	if (snd_pcm_running(substream) &&
 	    snd_pcm_update_hw_ptr(substream) >= 0)
 		runtime->status->hw_ptr %= runtime->buffer_size;
@@ -1753,7 +1753,6 @@ static int snd_pcm_lib_ioctl_reset(struct snd_pcm_substream *substream,
 		runtime->status->hw_ptr = 0;
 		runtime->hw_ptr_wrap = 0;
 	}
-	snd_pcm_stream_unlock_irqrestore(substream, flags);
 	return 0;
 }
 
@@ -1899,14 +1898,11 @@ EXPORT_SYMBOL(snd_pcm_period_elapsed_under_stream_lock);
  */
 void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
 {
-	unsigned long flags;
-
 	if (snd_BUG_ON(!substream))
 		return;
 
-	snd_pcm_stream_lock_irqsave(substream, flags);
+	guard(pcm_stream_lock_irqsave)(substream);
 	snd_pcm_period_elapsed_under_stream_lock(substream);
-	snd_pcm_stream_unlock_irqrestore(substream, flags);
 }
 EXPORT_SYMBOL(snd_pcm_period_elapsed);