ALSA: mixer_oss: Use guard() for locking

We can simplify the code gracefully with new guard() macro and co for
automatic cleanup of locks.

Only the code refactoring, and no functional changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240227085306.9764-8-tiwai@suse.de

1 files changed, 86 insertions, 142 deletions

diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
index e10017a42ed8ce..6a0508093ea688 100644
--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -130,13 +130,12 @@ static int snd_mixer_oss_devmask(struct snd_mixer_oss_file *fmixer)
 
 	if (mixer == NULL)
 		return -EIO;
-	mutex_lock(&mixer->reg_mutex);
+	guard(mutex)(&mixer->reg_mutex);
 	for (chn = 0; chn < 31; chn++) {
 		pslot = &mixer->slots[chn];
 		if (pslot->put_volume || pslot->put_recsrc)
 			result |= 1 << chn;
 	}
-	mutex_unlock(&mixer->reg_mutex);
 	return result;
 }
 
@@ -148,13 +147,12 @@ static int snd_mixer_oss_stereodevs(struct snd_mixer_oss_file *fmixer)
 
 	if (mixer == NULL)
 		return -EIO;
-	mutex_lock(&mixer->reg_mutex);
+	guard(mutex)(&mixer->reg_mutex);
 	for (chn = 0; chn < 31; chn++) {
 		pslot = &mixer->slots[chn];
 		if (pslot->put_volume && pslot->stereo)
 			result |= 1 << chn;
 	}
-	mutex_unlock(&mixer->reg_mutex);
 	return result;
 }
 
@@ -165,7 +163,7 @@ static int snd_mixer_oss_recmask(struct snd_mixer_oss_file *fmixer)
 
 	if (mixer == NULL)
 		return -EIO;
-	mutex_lock(&mixer->reg_mutex);
+	guard(mutex)(&mixer->reg_mutex);
 	if (mixer->put_recsrc && mixer->get_recsrc) {	/* exclusive */
 		result = mixer->mask_recsrc;
 	} else {
@@ -177,7 +175,6 @@ static int snd_mixer_oss_recmask(struct snd_mixer_oss_file *fmixer)
 				result |= 1 << chn;
 		}
 	}
-	mutex_unlock(&mixer->reg_mutex);
 	return result;
 }
 
@@ -188,12 +185,12 @@ static int snd_mixer_oss_get_recsrc(struct snd_mixer_oss_file *fmixer)
 
 	if (mixer == NULL)
 		return -EIO;
-	mutex_lock(&mixer->reg_mutex);
+	guard(mutex)(&mixer->reg_mutex);
 	if (mixer->put_recsrc && mixer->get_recsrc) {	/* exclusive */
 		unsigned int index;
 		result = mixer->get_recsrc(fmixer, &index);
 		if (result < 0)
-			goto unlock;
+			return result;
 		result = 1 << index;
 	} else {
 		struct snd_mixer_oss_slot *pslot;
@@ -209,8 +206,6 @@ static int snd_mixer_oss_get_recsrc(struct snd_mixer_oss_file *fmixer)
 		}
 	}
 	mixer->oss_recsrc = result;
- unlock:
-	mutex_unlock(&mixer->reg_mutex);
 	return result;
 }
 
@@ -224,7 +219,7 @@ static int snd_mixer_oss_set_recsrc(struct snd_mixer_oss_file *fmixer, int recsr
 
 	if (mixer == NULL)
 		return -EIO;
-	mutex_lock(&mixer->reg_mutex);
+	guard(mutex)(&mixer->reg_mutex);
 	if (mixer->get_recsrc && mixer->put_recsrc) {	/* exclusive input */
 		if (recsrc & ~mixer->oss_recsrc)
 			recsrc &= ~mixer->oss_recsrc;
@@ -250,7 +245,6 @@ static int snd_mixer_oss_set_recsrc(struct snd_mixer_oss_file *fmixer, int recsr
 			}
 		}
 	}
-	mutex_unlock(&mixer->reg_mutex);
 	return result;
 }
 
@@ -262,7 +256,7 @@ static int snd_mixer_oss_get_volume(struct snd_mixer_oss_file *fmixer, int slot)
 
 	if (mixer == NULL || slot > 30)
 		return -EIO;
-	mutex_lock(&mixer->reg_mutex);
+	guard(mutex)(&mixer->reg_mutex);
 	pslot = &mixer->slots[slot];
 	left = pslot->volume[0];
 	right = pslot->volume[1];
@@ -270,21 +264,15 @@ static int snd_mixer_oss_get_volume(struct snd_mixer_oss_file *fmixer, int slot)
 		result = pslot->get_volume(fmixer, pslot, &left, &right);
 	if (!pslot->stereo)
 		right = left;
-	if (snd_BUG_ON(left < 0 || left > 100)) {
-		result = -EIO;
-		goto unlock;
-	}
-	if (snd_BUG_ON(right < 0 || right > 100)) {
-		result = -EIO;
-		goto unlock;
-	}
+	if (snd_BUG_ON(left < 0 || left > 100))
+		return -EIO;
+	if (snd_BUG_ON(right < 0 || right > 100))
+		return -EIO;
 	if (result >= 0) {
 		pslot->volume[0] = left;
 		pslot->volume[1] = right;
 	 	result = (left & 0xff) | ((right & 0xff) << 8);
 	}
- unlock:
-	mutex_unlock(&mixer->reg_mutex);
 	return result;
 }
 
@@ -297,7 +285,7 @@ static int snd_mixer_oss_set_volume(struct snd_mixer_oss_file *fmixer,
 
 	if (mixer == NULL || slot > 30)
 		return -EIO;
-	mutex_lock(&mixer->reg_mutex);
+	guard(mutex)(&mixer->reg_mutex);
 	pslot = &mixer->slots[slot];
 	if (left > 100)
 		left = 100;
@@ -308,12 +296,10 @@ static int snd_mixer_oss_set_volume(struct snd_mixer_oss_file *fmixer,
 	if (pslot->put_volume)
 		result = pslot->put_volume(fmixer, pslot, left, right);
 	if (result < 0)
-		goto unlock;
+		return result;
 	pslot->volume[0] = left;
 	pslot->volume[1] = right;
 	result = (left & 0xff) | ((right & 0xff) << 8);
- unlock:
-	mutex_unlock(&mixer->reg_mutex);
 	return result;
 }
 
@@ -539,28 +525,24 @@ static void snd_mixer_oss_get_volume1_vol(struct snd_mixer_oss_file *fmixer,
 
 	if (numid == ID_UNKNOWN)
 		return;
-	down_read(&card->controls_rwsem);
+	guard(rwsem_read)(&card->controls_rwsem);
 	kctl = snd_ctl_find_numid_locked(card, numid);
-	if (!kctl) {
-		up_read(&card->controls_rwsem);
+	if (!kctl)
 		return;
-	}
 	uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
 	uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
 	if (uinfo == NULL || uctl == NULL)
-		goto __unalloc;
+		return;
 	if (kctl->info(kctl, uinfo))
-		goto __unalloc;
+		return;
 	if (kctl->get(kctl, uctl))
-		goto __unalloc;
+		return;
 	if (uinfo->type == SNDRV_CTL_ELEM_TYPE_BOOLEAN &&
 	    uinfo->value.integer.min == 0 && uinfo->value.integer.max == 1)
-		goto __unalloc;
+		return;
 	*left = snd_mixer_oss_conv1(uctl->value.integer.value[0], uinfo->value.integer.min, uinfo->value.integer.max, &pslot->volume[0]);
 	if (uinfo->count > 1)
 		*right = snd_mixer_oss_conv1(uctl->value.integer.value[1], uinfo->value.integer.min, uinfo->value.integer.max, &pslot->volume[1]);
-      __unalloc:
-	up_read(&card->controls_rwsem);
 }
 
 static void snd_mixer_oss_get_volume1_sw(struct snd_mixer_oss_file *fmixer,
@@ -576,20 +558,18 @@ static void snd_mixer_oss_get_volume1_sw(struct snd_mixer_oss_file *fmixer,
 
 	if (numid == ID_UNKNOWN)
 		return;
-	down_read(&card->controls_rwsem);
+	guard(rwsem_read)(&card->controls_rwsem);
 	kctl = snd_ctl_find_numid_locked(card, numid);
-	if (!kctl) {
-		up_read(&card->controls_rwsem);
+	if (!kctl)
 		return;
-	}
 	uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
 	uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
 	if (uinfo == NULL || uctl == NULL)
-		goto __unalloc;
+		return;
 	if (kctl->info(kctl, uinfo))
-		goto __unalloc;
+		return;
 	if (kctl->get(kctl, uctl))
-		goto __unalloc;
+		return;
 	if (!uctl->value.integer.value[0]) {
 		*left = 0;
 		if (uinfo->count == 1)
@@ -597,8 +577,6 @@ static void snd_mixer_oss_get_volume1_sw(struct snd_mixer_oss_file *fmixer,
 	}
 	if (uinfo->count > 1 && !uctl->value.integer.value[route ? 3 : 1])
 		*right = 0;
-      __unalloc:
-	up_read(&card->controls_rwsem);
 }
 
 static int snd_mixer_oss_get_volume1(struct snd_mixer_oss_file *fmixer,
@@ -640,31 +618,27 @@ static void snd_mixer_oss_put_volume1_vol(struct snd_mixer_oss_file *fmixer,
 
 	if (numid == ID_UNKNOWN)
 		return;
-	down_read(&card->controls_rwsem);
+	guard(rwsem_read)(&card->controls_rwsem);
 	kctl = snd_ctl_find_numid_locked(card, numid);
-	if (!kctl) {
-		up_read(&card->controls_rwsem);
+	if (!kctl)
 		return;
-	}
 	uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
 	uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
 	if (uinfo == NULL || uctl == NULL)
-		goto __unalloc;
+		return;
 	if (kctl->info(kctl, uinfo))
-		goto __unalloc;
+		return;
 	if (uinfo->type == SNDRV_CTL_ELEM_TYPE_BOOLEAN &&
 	    uinfo->value.integer.min == 0 && uinfo->value.integer.max == 1)
-		goto __unalloc;
+		return;
 	uctl->value.integer.value[0] = snd_mixer_oss_conv2(left, uinfo->value.integer.min, uinfo->value.integer.max);
 	if (uinfo->count > 1)
 		uctl->value.integer.value[1] = snd_mixer_oss_conv2(right, uinfo->value.integer.min, uinfo->value.integer.max);
 	res = kctl->put(kctl, uctl);
 	if (res < 0)
-		goto __unalloc;
+		return;
 	if (res > 0)
 		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &kctl->id);
-      __unalloc:
-	up_read(&card->controls_rwsem);
 }
 
 static void snd_mixer_oss_put_volume1_sw(struct snd_mixer_oss_file *fmixer,
@@ -681,18 +655,16 @@ static void snd_mixer_oss_put_volume1_sw(struct snd_mixer_oss_file *fmixer,
 
 	if (numid == ID_UNKNOWN)
 		return;
-	down_read(&card->controls_rwsem);
+	guard(rwsem_read)(&card->controls_rwsem);
 	kctl = snd_ctl_find_numid_locked(card, numid);
-	if (!kctl) {
-		up_read(&card->controls_rwsem);
+	if (!kctl)
 		return;
-	}
 	uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
 	uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
 	if (uinfo == NULL || uctl == NULL)
-		goto __unalloc;
+		return;
 	if (kctl->info(kctl, uinfo))
-		goto __unalloc;
+		return;
 	if (uinfo->count > 1) {
 		uctl->value.integer.value[0] = left > 0 ? 1 : 0;
 		uctl->value.integer.value[route ? 3 : 1] = right > 0 ? 1 : 0;
@@ -705,11 +677,9 @@ static void snd_mixer_oss_put_volume1_sw(struct snd_mixer_oss_file *fmixer,
 	}
 	res = kctl->put(kctl, uctl);
 	if (res < 0)
-		goto __unalloc;
+		return;
 	if (res > 0)
 		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &kctl->id);
-      __unalloc:
-	up_read(&card->controls_rwsem);
 }
 
 static int snd_mixer_oss_put_volume1(struct snd_mixer_oss_file *fmixer,
@@ -822,18 +792,16 @@ static int snd_mixer_oss_get_recsrc2(struct snd_mixer_oss_file *fmixer, unsigned
 	uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
 	if (uinfo == NULL || uctl == NULL)
 		return -ENOMEM;
-	down_read(&card->controls_rwsem);
+	guard(rwsem_read)(&card->controls_rwsem);
 	kctl = snd_mixer_oss_test_id(mixer, "Capture Source", 0);
-	if (! kctl) {
-		err = -ENOENT;
-		goto __unlock;
-	}
+	if (!kctl)
+		return -ENOENT;
 	err = kctl->info(kctl, uinfo);
 	if (err < 0)
-		goto __unlock;
+		return err;
 	err = kctl->get(kctl, uctl);
 	if (err < 0)
-		goto __unlock;
+		return err;
 	for (idx = 0; idx < 32; idx++) {
 		if (!(mixer->mask_recsrc & (1 << idx)))
 			continue;
@@ -848,10 +816,7 @@ static int snd_mixer_oss_get_recsrc2(struct snd_mixer_oss_file *fmixer, unsigned
 			break;
 		}
 	}
-	err = 0;
-      __unlock:
-     	up_read(&card->controls_rwsem);
-      	return err;
+	return 0;
 }
 
 static int snd_mixer_oss_put_recsrc2(struct snd_mixer_oss_file *fmixer, unsigned int active_index)
@@ -870,15 +835,13 @@ static int snd_mixer_oss_put_recsrc2(struct snd_mixer_oss_file *fmixer, unsigned
 	uctl = kzalloc(sizeof(*uctl), GFP_KERNEL);
 	if (uinfo == NULL || uctl == NULL)
 		return -ENOMEM;
-	down_read(&card->controls_rwsem);
+	guard(rwsem_read)(&card->controls_rwsem);
 	kctl = snd_mixer_oss_test_id(mixer, "Capture Source", 0);
-	if (! kctl) {
-		err = -ENOENT;
-		goto __unlock;
-	}
+	if (!kctl)
+		return -ENOENT;
 	err = kctl->info(kctl, uinfo);
 	if (err < 0)
-		goto __unlock;
+		return err;
 	for (idx = 0; idx < 32; idx++) {
 		if (!(mixer->mask_recsrc & (1 << idx)))
 			continue;
@@ -892,17 +855,14 @@ static int snd_mixer_oss_put_recsrc2(struct snd_mixer_oss_file *fmixer, unsigned
 			break;
 		slot = NULL;
 	}
-	if (! slot)
-		goto __unlock;
+	if (!slot)
+		return 0;
 	for (idx = 0; idx < uinfo->count; idx++)
 		uctl->value.enumerated.item[idx] = slot->capture_item;
 	err = kctl->put(kctl, uctl);
 	if (err > 0)
 		snd_ctl_notify(fmixer->card, SNDRV_CTL_EVENT_MASK_VALUE, &kctl->id);
-	err = 0;
-      __unlock:
-	up_read(&card->controls_rwsem);
-	return err;
+	return 0;
 }
 
 struct snd_mixer_oss_assign_table {
@@ -918,24 +878,18 @@ static int snd_mixer_oss_build_test(struct snd_mixer_oss *mixer, struct slot *sl
 	struct snd_card *card = mixer->card;
 	int err;
 
-	down_read(&card->controls_rwsem);
-	kcontrol = snd_mixer_oss_test_id(mixer, name, index);
-	if (kcontrol == NULL) {
-		up_read(&card->controls_rwsem);
-		return 0;
-	}
-	info = kmalloc(sizeof(*info), GFP_KERNEL);
-	if (! info) {
-		up_read(&card->controls_rwsem);
-		return -ENOMEM;
-	}
-	err = kcontrol->info(kcontrol, info);
-	if (err < 0) {
-		up_read(&card->controls_rwsem);
-		return err;
+	scoped_guard(rwsem_read, &card->controls_rwsem) {
+		kcontrol = snd_mixer_oss_test_id(mixer, name, index);
+		if (kcontrol == NULL)
+			return 0;
+		info = kmalloc(sizeof(*info), GFP_KERNEL);
+		if (!info)
+			return -ENOMEM;
+		err = kcontrol->info(kcontrol, info);
+		if (err < 0)
+			return err;
+		slot->numid[item] = kcontrol->id.numid;
 	}
-	slot->numid[item] = kcontrol->id.numid;
-	up_read(&card->controls_rwsem);
 	if (info->count > slot->channels)
 		slot->channels = info->count;
 	slot->present |= 1 << item;
@@ -1048,7 +1002,7 @@ static int snd_mixer_oss_build_input(struct snd_mixer_oss *mixer,
 	memset(slot.numid, 0xff, sizeof(slot.numid)); /* ID_UNKNOWN */
 	if (snd_mixer_oss_build_test_all(mixer, ptr, &slot))
 		return 0;
-	down_read(&mixer->card->controls_rwsem);
+	guard(rwsem_read)(&mixer->card->controls_rwsem);
 	kctl = NULL;
 	if (!ptr->index)
 		kctl = snd_mixer_oss_test_id(mixer, "Capture Source", 0);
@@ -1056,15 +1010,11 @@ static int snd_mixer_oss_build_input(struct snd_mixer_oss *mixer,
 		struct snd_ctl_elem_info *uinfo __free(kfree) = NULL;
 
 		uinfo = kzalloc(sizeof(*uinfo), GFP_KERNEL);
-		if (! uinfo) {
-			up_read(&mixer->card->controls_rwsem);
+		if (!uinfo)
 			return -ENOMEM;
-		}
 			
-		if (kctl->info(kctl, uinfo)) {
-			up_read(&mixer->card->controls_rwsem);
+		if (kctl->info(kctl, uinfo))
 			return 0;
-		}
 		strcpy(str, ptr->name);
 		if (!strcmp(str, "Master"))
 			strcpy(str, "Mix");
@@ -1076,10 +1026,8 @@ static int snd_mixer_oss_build_input(struct snd_mixer_oss *mixer,
 		} else {
 			for (slot.capture_item = 1; slot.capture_item < uinfo->value.enumerated.items; slot.capture_item++) {
 				uinfo->value.enumerated.item = slot.capture_item;
-				if (kctl->info(kctl, uinfo)) {
-					up_read(&mixer->card->controls_rwsem);
+				if (kctl->info(kctl, uinfo))
 					return 0;
-				}
 				if (!strcmp(uinfo->value.enumerated.name, str)) {
 					slot.present |= SNDRV_MIXER_OSS_PRESENT_CAPTURE;
 					break;
@@ -1087,7 +1035,6 @@ static int snd_mixer_oss_build_input(struct snd_mixer_oss *mixer,
 			}
 		}
 	}
-	up_read(&mixer->card->controls_rwsem);
 	if (slot.present != 0) {
 		pslot = kmalloc(sizeof(slot), GFP_KERNEL);
 		if (! pslot)
@@ -1160,7 +1107,7 @@ static void snd_mixer_oss_proc_read(struct snd_info_entry *entry,
 	struct snd_mixer_oss *mixer = entry->private_data;
 	int i;
 
-	mutex_lock(&mixer->reg_mutex);
+	guard(mutex)(&mixer->reg_mutex);
 	for (i = 0; i < SNDRV_OSS_MAX_MIXERS; i++) {
 		struct slot *p;
 
@@ -1175,7 +1122,6 @@ static void snd_mixer_oss_proc_read(struct snd_info_entry *entry,
 		else
 			snd_iprintf(buffer, "\"\" 0\n");
 	}
-	mutex_unlock(&mixer->reg_mutex);
 }
 
 static void snd_mixer_oss_proc_write(struct snd_info_entry *entry,
@@ -1202,9 +1148,8 @@ static void snd_mixer_oss_proc_write(struct snd_info_entry *entry,
 		cptr = snd_info_get_str(str, cptr, sizeof(str));
 		if (! *str) {
 			/* remove the entry */
-			mutex_lock(&mixer->reg_mutex);
-			mixer_slot_clear(&mixer->slots[ch]);
-			mutex_unlock(&mixer->reg_mutex);
+			scoped_guard(mutex, &mixer->reg_mutex)
+				mixer_slot_clear(&mixer->slots[ch]);
 			continue;
 		}
 		snd_info_get_str(idxstr, cptr, sizeof(idxstr));
@@ -1213,28 +1158,27 @@ static void snd_mixer_oss_proc_write(struct snd_info_entry *entry,
 			pr_err("ALSA: mixer_oss: invalid index %d\n", idx);
 			continue;
 		}
-		mutex_lock(&mixer->reg_mutex);
-		slot = (struct slot *)mixer->slots[ch].private_data;
-		if (slot && slot->assigned &&
-		    slot->assigned->index == idx && ! strcmp(slot->assigned->name, str))
-			/* not changed */
-			goto __unlock;
-		tbl = kmalloc(sizeof(*tbl), GFP_KERNEL);
-		if (!tbl)
-			goto __unlock;
-		tbl->oss_id = ch;
-		tbl->name = kstrdup(str, GFP_KERNEL);
-		if (! tbl->name) {
-			kfree(tbl);
-			goto __unlock;
-		}
-		tbl->index = idx;
-		if (snd_mixer_oss_build_input(mixer, tbl, 1, 1) <= 0) {
-			kfree(tbl->name);
-			kfree(tbl);
+		scoped_guard(mutex, &mixer->reg_mutex) {
+			slot = (struct slot *)mixer->slots[ch].private_data;
+			if (slot && slot->assigned &&
+			    slot->assigned->index == idx && !strcmp(slot->assigned->name, str))
+				/* not changed */
+				break;
+			tbl = kmalloc(sizeof(*tbl), GFP_KERNEL);
+			if (!tbl)
+				break;
+			tbl->oss_id = ch;
+			tbl->name = kstrdup(str, GFP_KERNEL);
+			if (!tbl->name) {
+				kfree(tbl);
+				break;
+			}
+			tbl->index = idx;
+			if (snd_mixer_oss_build_input(mixer, tbl, 1, 1) <= 0) {
+				kfree(tbl->name);
+				kfree(tbl);
+			}
 		}
-	__unlock:
-		mutex_unlock(&mixer->reg_mutex);
 	}
 }