Merge branch 'topic/pci-rescan-prep-v2' into for-next

Pull PCI rescan prep work.

Link: https://lore.kernel.org/r/20210523090920.15345-1-tiwai@suse.de

7 files changed, 113 insertions, 45 deletions

diff --git a/include/sound/core.h b/include/sound/core.h
index 1f9aef0adbc9..c4ade121727d 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -128,7 +128,9 @@ struct snd_card {
 
 #ifdef CONFIG_PM
 	unsigned int power_state;	/* power state */
+	atomic_t power_ref;
 	wait_queue_head_t power_sleep;
+	wait_queue_head_t power_ref_sleep;
 #endif
 
 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
@@ -142,21 +144,61 @@ struct snd_card {
 #ifdef CONFIG_PM
 static inline unsigned int snd_power_get_state(struct snd_card *card)
 {
-	return card->power_state;
+	return READ_ONCE(card->power_state);
 }
 
 static inline void snd_power_change_state(struct snd_card *card, unsigned int state)
 {
-	card->power_state = state;
+	WRITE_ONCE(card->power_state, state);
 	wake_up(&card->power_sleep);
 }
 
+/**
+ * snd_power_ref - Take the reference count for power control
+ * @card: sound card object
+ *
+ * The power_ref reference of the card is used for managing to block
+ * the snd_power_sync_ref() operation.  This function increments the reference.
+ * The counterpart snd_power_unref() has to be called appropriately later.
+ */
+static inline void snd_power_ref(struct snd_card *card)
+{
+	atomic_inc(&card->power_ref);
+}
+
+/**
+ * snd_power_unref - Release the reference count for power control
+ * @card: sound card object
+ */
+static inline void snd_power_unref(struct snd_card *card)
+{
+	if (atomic_dec_and_test(&card->power_ref))
+		wake_up(&card->power_ref_sleep);
+}
+
+/**
+ * snd_power_sync_ref - wait until the card power_ref is freed
+ * @card: sound card object
+ *
+ * This function is used to synchronize with the pending power_ref being
+ * released.
+ */
+static inline void snd_power_sync_ref(struct snd_card *card)
+{
+	wait_event(card->power_ref_sleep, !atomic_read(&card->power_ref));
+}
+
 /* init.c */
-int snd_power_wait(struct snd_card *card, unsigned int power_state);
+int snd_power_wait(struct snd_card *card);
+int snd_power_ref_and_wait(struct snd_card *card);
 
 #else /* ! CONFIG_PM */
 
-static inline int snd_power_wait(struct snd_card *card, unsigned int state) { return 0; }
+static inline int snd_power_wait(struct snd_card *card) { return 0; }
+static inline void snd_power_ref(struct snd_card *card) {}
+static inline void snd_power_unref(struct snd_card *card) {}
+static inline int snd_power_ref_and_wait(struct snd_card *card) { return 0; }
+static inline void snd_power_sync_ref(struct snd_card *card) {}
 #define snd_power_get_state(card)	({ (void)(card); SNDRV_CTL_POWER_D0; })
 #define snd_power_change_state(card, state)	do { (void)(card); } while (0)
 
diff --git a/sound/core/control.c b/sound/core/control.c
index 498e3701514a..a25c0d64d104 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -995,7 +995,10 @@ static int __snd_ctl_elem_info(struct snd_card *card,
 #ifdef CONFIG_SND_DEBUG
 	info->access = 0;
 #endif
-	result = kctl->info(kctl, info);
+	result = snd_power_ref_and_wait(card);
+	if (!result)
+		result = kctl->info(kctl, info);
+	snd_power_unref(card);
 	if (result >= 0) {
 		snd_BUG_ON(info->access);
 		index_offset = snd_ctl_get_ioff(kctl, &info->id);
@@ -1042,9 +1045,6 @@ static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 
 	if (copy_from_user(&info, _info, sizeof(info)))
 		return -EFAULT;
-	result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
-	if (result < 0)
-		return result;
 	result = snd_ctl_elem_info(ctl, &info);
 	if (result < 0)
 		return result;
@@ -1088,7 +1088,10 @@ static int snd_ctl_elem_read(struct snd_card *card,
 
 	if (!snd_ctl_skip_validation(&info))
 		fill_remaining_elem_value(control, &info, pattern);
-	ret = kctl->get(kctl, control);
+	ret = snd_power_ref_and_wait(card);
+	if (!ret)
+		ret = kctl->get(kctl, control);
+	snd_power_unref(card);
 	if (ret < 0)
 		return ret;
 	if (!snd_ctl_skip_validation(&info) &&
@@ -1113,10 +1116,6 @@ static int snd_ctl_elem_read_user(struct snd_card *card,
 	if (IS_ERR(control))
 		return PTR_ERR(control);
 
-	result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
-	if (result < 0)
-		goto error;
-
 	down_read(&card->controls_rwsem);
 	result = snd_ctl_elem_read(card, control);
 	up_read(&card->controls_rwsem);
@@ -1154,7 +1153,10 @@ static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 	}
 
 	snd_ctl_build_ioff(&control->id, kctl, index_offset);
-	result = kctl->put(kctl, control);
+	result = snd_power_ref_and_wait(card);
+	if (!result)
+		result = kctl->put(kctl, control);
+	snd_power_unref(card);
 	if (result < 0) {
 		up_write(&card->controls_rwsem);
 		return result;
@@ -1183,10 +1185,6 @@ static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 		return PTR_ERR(control);
 
 	card = file->card;
-	result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
-	if (result < 0)
-		goto error;
-
 	result = snd_ctl_elem_write(card, file, control);
 	if (result < 0)
 		goto error;
@@ -1669,7 +1667,7 @@ static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
 		{SNDRV_CTL_TLV_OP_CMD,   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
 	};
 	struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
-	int i;
+	int i, ret;
 
 	/* Check support of the request for this element. */
 	for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
@@ -1687,7 +1685,11 @@ static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
 	    vd->owner != NULL && vd->owner != file)
 		return -EPERM;
 
-	return kctl->tlv.c(kctl, op_flag, size, buf);
+	ret = snd_power_ref_and_wait(file->card);
+	if (!ret)
+		ret = kctl->tlv.c(kctl, op_flag, size, buf);
+	snd_power_unref(file->card);
+	return ret;
 }
 
 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
@@ -1815,11 +1817,7 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
 	case SNDRV_CTL_IOCTL_POWER:
 		return -ENOPROTOOPT;
 	case SNDRV_CTL_IOCTL_POWER_STATE:
-#ifdef CONFIG_PM
-		return put_user(card->power_state, ip) ? -EFAULT : 0;
-#else
 		return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
-#endif
 	}
 	down_read(&snd_ioctl_rwsem);
 	list_for_each_entry(p, &snd_control_ioctls, list) {
diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c
index 1d708aab9c98..470dabc60aa0 100644
--- a/sound/core/control_compat.c
+++ b/sound/core/control_compat.c
@@ -96,9 +96,6 @@ static int snd_ctl_elem_info_compat(struct snd_ctl_file *ctl,
 	if (get_user(data->value.enumerated.item, &data32->value.enumerated.item))
 		goto error;
 
-	err = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
-	if (err < 0)
-		goto error;
 	err = snd_ctl_elem_info(ctl, data);
 	if (err < 0)
 		goto error;
@@ -187,7 +184,10 @@ static int get_ctl_type(struct snd_card *card, struct snd_ctl_elem_id *id,
 		return -ENOMEM;
 	}
 	info->id = *id;
-	err = kctl->info(kctl, info);
+	err = snd_power_ref_and_wait(card);
+	if (!err)
+		err = kctl->info(kctl, info);
+	snd_power_unref(card);
 	up_read(&card->controls_rwsem);
 	if (err >= 0) {
 		err = info->type;
@@ -298,9 +298,6 @@ static int ctl_elem_read_user(struct snd_card *card,
 	if (err < 0)
 		goto error;
 
-	err = snd_power_wait(card, SNDRV_CTL_POWER_D0);
-	if (err < 0)
-		goto error;
 	err = snd_ctl_elem_read(card, data);
 	if (err < 0)
 		goto error;
@@ -326,9 +323,6 @@ static int ctl_elem_write_user(struct snd_ctl_file *file,
 	if (err < 0)
 		goto error;
 
-	err = snd_power_wait(card, SNDRV_CTL_POWER_D0);
-	if (err < 0)
-		goto error;
 	err = snd_ctl_elem_write(card, file, data);
 	if (err < 0)
 		goto error;
diff --git a/sound/core/init.c b/sound/core/init.c
index ef41f5b3a240..70114fd26956 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -220,6 +220,8 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 	mutex_init(&card->memory_mutex);
 #ifdef CONFIG_PM
 	init_waitqueue_head(&card->power_sleep);
+	init_waitqueue_head(&card->power_ref_sleep);
+	atomic_set(&card->power_ref, 0);
 #endif
 	init_waitqueue_head(&card->remove_sleep);
 	card->sync_irq = -1;
@@ -442,6 +444,7 @@ int snd_card_disconnect(struct snd_card *card)
 
 #ifdef CONFIG_PM
 	wake_up(&card->power_sleep);
+	snd_power_sync_ref(card);
 #endif
 	return 0;	
 }
@@ -1002,21 +1005,28 @@ EXPORT_SYMBOL(snd_card_file_remove);
 
 #ifdef CONFIG_PM
 /**
- *  snd_power_wait - wait until the power-state is changed.
- *  @card: soundcard structure
- *  @power_state: expected power state
+ * snd_power_ref_and_wait - wait until the card gets powered up
+ * @card: soundcard structure
  *
- *  Waits until the power-state is changed.
+ * Take the power_ref reference count of the given card, and
+ * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
+ * The refcount is down again while sleeping until power-up, hence this
+ * function can be used for syncing the floating control ops accesses,
+ * typically around calling control ops.
  *
- *  Return: Zero if successful, or a negative error code.
+ * The caller needs to pull down the refcount via snd_power_unref() later
+ * no matter whether the error is returned from this function or not.
+ *
+ * Return: Zero if successful, or a negative error code.
  */
-int snd_power_wait(struct snd_card *card, unsigned int power_state)
+int snd_power_ref_and_wait(struct snd_card *card)
 {
 	wait_queue_entry_t wait;
 	int result = 0;
 
+	snd_power_ref(card);
 	/* fastpath */
-	if (snd_power_get_state(card) == power_state)
+	if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
 		return 0;
 	init_waitqueue_entry(&wait, current);
 	add_wait_queue(&card->power_sleep, &wait);
@@ -1025,13 +1035,33 @@ int snd_power_wait(struct snd_card *card, unsigned int power_state)
 			result = -ENODEV;
 			break;
 		}
-		if (snd_power_get_state(card) == power_state)
+		if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
 			break;
+		snd_power_unref(card);
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		schedule_timeout(30 * HZ);
+		snd_power_ref(card);
 	}
 	remove_wait_queue(&card->power_sleep, &wait);
 	return result;
 }
+EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
+
+/**
+ * snd_power_wait - wait until the card gets powered up (old form)
+ * @card: soundcard structure
+ *
+ * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
+ *
+ * Return: Zero if successful, or a negative error code.
+ */
+int snd_power_wait(struct snd_card *card)
+{
+	int ret;
+
+	ret = snd_power_ref_and_wait(card);
+	snd_power_unref(card);
+	return ret;
+}
 EXPORT_SYMBOL(snd_power_wait);
 #endif /* CONFIG_PM */
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 8dbe86cf2e4f..11acea02bc74 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -2799,6 +2799,10 @@ static int snd_pcm_release(struct inode *inode, struct file *file)
 	if (snd_BUG_ON(!substream))
 		return -ENXIO;
 	pcm = substream->pcm;
+
+	/* block until the device gets woken up as it may touch the hardware */
+	snd_power_wait(pcm->card);
+
 	mutex_lock(&pcm->open_mutex);
 	snd_pcm_release_substream(substream);
 	kfree(pcm_file);
@@ -3193,7 +3197,7 @@ static int snd_pcm_common_ioctl(struct file *file,
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
 
-	res = snd_power_wait(substream->pcm->card, SNDRV_CTL_POWER_D0);
+	res = snd_power_wait(substream->pcm->card);
 	if (res < 0)
 		return res;
 
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 1c0904acb935..ddc65c12f6f4 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -580,7 +580,7 @@ int snd_soc_suspend(struct device *dev)
 	 * Due to the resume being scheduled into a workqueue we could
 	 * suspend before that's finished - wait for it to complete.
 	 */
-	snd_power_wait(card->snd_card, SNDRV_CTL_POWER_D0);
+	snd_power_wait(card->snd_card);
 
 	/* we're going to block userspace touching us until resume completes */
 	snd_power_change_state(card->snd_card, SNDRV_CTL_POWER_D3hot);
diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c
index 0b0a87a631a0..e558931cce16 100644
--- a/sound/usb/usx2y/us122l.c
+++ b/sound/usb/usx2y/us122l.c
@@ -385,7 +385,7 @@ static int usb_stream_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
 	if (cfg.period_frames < min_period_frames)
 		return -EINVAL;
 
-	snd_power_wait(hw->card, SNDRV_CTL_POWER_D0);
+	snd_power_wait(hw->card);
 
 	mutex_lock(&us122l->mutex);
 	s = us122l->sk.s;