ALSA: Remove BKL from open multiplexer

Use a local mutex instead of BKL. This should suffice since each device type has also its open_mutex. Also, a bit of clean-up of the legacy device auto-loading code. Signed-off-by: Takashi Iwai <tiwai@suse.de>

ALSA: Remove BKL from open multiplexer
Use a local mutex instead of BKL. This should suffice since each device type has also its open_mutex. Also, a bit of clean-up of the legacy device auto-loading code. Signed-off-by: Takashi Iwai <tiwai@suse.de>
Takashi Iwai
1 parent 5b5cd553e3
Showing 1 changed file with 38 additions and 35 deletions Side-by-side Diff
sound/core/sound.c
@@ -120,8 +120,30 @@
  
 EXPORT_SYMBOL(snd_lookup_minor_data);
  
-static int __snd_open(struct inode *inode, struct file *file)
+#ifdef CONFIG_MODULES
+static struct snd_minor *autoload_device(unsigned int minor)
 {
+	int dev;
+	mutex_unlock(&sound_mutex); /* release lock temporarily */
+	dev = SNDRV_MINOR_DEVICE(minor);
+	if (dev == SNDRV_MINOR_CONTROL) {
+		/* /dev/aloadC? */
+		int card = SNDRV_MINOR_CARD(minor);
+		if (snd_cards[card] == NULL)
+			snd_request_card(card);
+	} else if (dev == SNDRV_MINOR_GLOBAL) {
+		/* /dev/aloadSEQ */
+		snd_request_other(minor);
+	}
+	mutex_lock(&sound_mutex); /* reacuire lock */
+	return snd_minors[minor];
+}
+#else /* !CONFIG_MODULES */
+#define autoload_device(minor)	NULL
+#endif /* CONFIG_MODULES */
+
+static int snd_open(struct inode *inode, struct file *file)
+{
 	unsigned int minor = iminor(inode);
 	struct snd_minor *mptr = NULL;
 	const struct file_operations *old_fops;
  
  
  
  
  
  
@@ -129,53 +151,34 @@
  
 	if (minor >= ARRAY_SIZE(snd_minors))
 		return -ENODEV;
+	mutex_lock(&sound_mutex);
 	mptr = snd_minors[minor];
 	if (mptr == NULL) {
-#ifdef CONFIG_MODULES
-		int dev = SNDRV_MINOR_DEVICE(minor);
-		if (dev == SNDRV_MINOR_CONTROL) {
-			/* /dev/aloadC? */
-			int card = SNDRV_MINOR_CARD(minor);
-			if (snd_cards[card] == NULL)
-				snd_request_card(card);
-		} else if (dev == SNDRV_MINOR_GLOBAL) {
-			/* /dev/aloadSEQ */
-			snd_request_other(minor);
-		}
-#ifndef CONFIG_SND_DYNAMIC_MINORS
-		/* /dev/snd/{controlC?,seq} */
-		mptr = snd_minors[minor];
-		if (mptr == NULL)
-#endif
-#endif
+		mptr = autoload_device(minor);
+		if (!mptr) {
+			mutex_unlock(&sound_mutex);
 			return -ENODEV;
+		}
 	}
 	old_fops = file->f_op;
 	file->f_op = fops_get(mptr->f_ops);
 	if (file->f_op == NULL) {
 		file->f_op = old_fops;
-		return -ENODEV;
+		err = -ENODEV;
 	}
-	if (file->f_op->open)
+	mutex_unlock(&sound_mutex);
+	if (err < 0)
+		return err;
+
+	if (file->f_op->open) {
 		err = file->f_op->open(inode, file);
-	if (err) {
-		fops_put(file->f_op);
-		file->f_op = fops_get(old_fops);
+		if (err) {
+			fops_put(file->f_op);
+			file->f_op = fops_get(old_fops);
+		}
 	}
 	fops_put(old_fops);
 	return err;
-}
-
-
-/* BKL pushdown: nasty #ifdef avoidance wrapper */
-static int snd_open(struct inode *inode, struct file *file)
-{
-	int ret;
-
-	lock_kernel();
-	ret = __snd_open(inode, file);
-	unlock_kernel();
-	return ret;
 }
  
 static const struct file_operations snd_fops =
...	...	@@ -120,8 +120,30 @@
120	120
121	121	EXPORT_SYMBOL(snd_lookup_minor_data);
122	122
123		-static int __snd_open(struct inode inode, struct file file)
	123	+#ifdef CONFIG_MODULES
	124	+static struct snd_minor *autoload_device(unsigned int minor)
124	125	{
	126	+ int dev;
	127	+ mutex_unlock(&sound_mutex); /* release lock temporarily */
	128	+ dev = SNDRV_MINOR_DEVICE(minor);
	129	+ if (dev == SNDRV_MINOR_CONTROL) {
	130	+ /* /dev/aloadC? */
	131	+ int card = SNDRV_MINOR_CARD(minor);
	132	+ if (snd_cards[card] == NULL)
	133	+ snd_request_card(card);
	134	+ } else if (dev == SNDRV_MINOR_GLOBAL) {
	135	+ /* /dev/aloadSEQ */
	136	+ snd_request_other(minor);
	137	+ }
	138	+ mutex_lock(&sound_mutex); /* reacuire lock */
	139	+ return snd_minors[minor];
	140	+}
	141	+#else /* !CONFIG_MODULES */
	142	+#define autoload_device(minor) NULL
	143	+#endif /* CONFIG_MODULES */
	144	+
	145	+static int snd_open(struct inode inode, struct file file)
	146	+{
125	147	unsigned int minor = iminor(inode);
126	148	struct snd_minor *mptr = NULL;
127	149	const struct file_operations *old_fops;
128	150
129	151
130	152
131	153
132	154
133	155
...	...	@@ -129,53 +151,34 @@
129	151
130	152	if (minor >= ARRAY_SIZE(snd_minors))
131	153	return -ENODEV;
	154	+ mutex_lock(&sound_mutex);
132	155	mptr = snd_minors[minor];
133	156	if (mptr == NULL) {
134		-#ifdef CONFIG_MODULES
135		- int dev = SNDRV_MINOR_DEVICE(minor);
136		- if (dev == SNDRV_MINOR_CONTROL) {
137		- /* /dev/aloadC? */
138		- int card = SNDRV_MINOR_CARD(minor);
139		- if (snd_cards[card] == NULL)
140		- snd_request_card(card);
141		- } else if (dev == SNDRV_MINOR_GLOBAL) {
142		- /* /dev/aloadSEQ */
143		- snd_request_other(minor);
144		- }
145		-#ifndef CONFIG_SND_DYNAMIC_MINORS
146		- /* /dev/snd/{controlC?,seq} */
147		- mptr = snd_minors[minor];
148		- if (mptr == NULL)
149		-#endif
150		-#endif
	157	+ mptr = autoload_device(minor);
	158	+ if (!mptr) {
	159	+ mutex_unlock(&sound_mutex);
151	160	return -ENODEV;
	161	+ }
152	162	}
153	163	old_fops = file->f_op;
154	164	file->f_op = fops_get(mptr->f_ops);
155	165	if (file->f_op == NULL) {
156	166	file->f_op = old_fops;
157		- return -ENODEV;
	167	+ err = -ENODEV;
158	168	}
159		- if (file->f_op->open)
	169	+ mutex_unlock(&sound_mutex);
	170	+ if (err < 0)
	171	+ return err;
	172	+
	173	+ if (file->f_op->open) {
160	174	err = file->f_op->open(inode, file);
161		- if (err) {
162		- fops_put(file->f_op);
163		- file->f_op = fops_get(old_fops);
	175	+ if (err) {
	176	+ fops_put(file->f_op);
	177	+ file->f_op = fops_get(old_fops);
	178	+ }
164	179	}
165	180	fops_put(old_fops);
166	181	return err;
167		-}
168		-
169		-
170		-/* BKL pushdown: nasty #ifdef avoidance wrapper */
171		-static int snd_open(struct inode inode, struct file file)
172		-{
173		- int ret;
174		-
175		- lock_kernel();
176		- ret = __snd_open(inode, file);
177		- unlock_kernel();
178		- return ret;
179	182	}
180	183
181	184	static const struct file_operations snd_fops =