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>

1 files changed, 38 insertions, 35 deletions

diff --git a/sound/core/sound.c b/sound/core/sound.c
index 563d1967a0ad..ac42af42b787 100644
--- a/sound/core/sound.c
+++ b/sound/core/sound.c
@@ -120,7 +120,29 @@ void *snd_lookup_minor_data(unsigned int minor, int type)
 
 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;
@@ -129,55 +151,36 @@ static int __snd_open(struct inode *inode, struct file *file)
 
         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 =
 {
         .owner =        THIS_MODULE,