sound: push BKL into open functions

This moves the lock_kernel() call from soundcore_open
to the individual OSS device drivers, where we can deal
with it one driver at a time if needed, or just kill
off the drivers.

All core components in ALSA already provide
adequate locking in their open()-functions
and do not require the big kernel lock, so
there is no need to add the BKL there.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/oss/soundcard.c

@@ -210,42 +210,44 @@ static int sound_open(struct inode *inode, struct file *file)
 		printk(KERN_ERR "Invalid minor device %d\n", dev);
 		return -ENXIO;
 	}
+	lock_kernel();
 	switch (dev & 0x0f) {
 	case SND_DEV_CTL:
 		dev >>= 4;
 		if (dev >= 0 && dev < MAX_MIXER_DEV && mixer_devs[dev] == NULL) {
 			request_module("mixer%d", dev);
 		}
+		retval = -ENXIO;
 		if (dev && (dev >= num_mixers || mixer_devs[dev] == NULL))
-			return -ENXIO;
+			break;
 	
 		if (!try_module_get(mixer_devs[dev]->owner))
-			return -ENXIO;
+			break;
+
+		retval = 0;
 		break;
 
 	case SND_DEV_SEQ:
 	case SND_DEV_SEQ2:
-		if ((retval = sequencer_open(dev, file)) < 0)
-			return retval;
+		retval = sequencer_open(dev, file);
 		break;
 
 	case SND_DEV_MIDIN:
-		if ((retval = MIDIbuf_open(dev, file)) < 0)
-			return retval;
+		retval = MIDIbuf_open(dev, file);
 		break;
 
 	case SND_DEV_DSP:
 	case SND_DEV_DSP16:
 	case SND_DEV_AUDIO:
-		if ((retval = audio_open(dev, file)) < 0)
-			return retval;
+		retval = audio_open(dev, file);
 		break;
 
 	default:
 		printk(KERN_ERR "Invalid minor device %d\n", dev);
-		return -ENXIO;
+		retval = -ENXIO;
 	}
 
+	unlock_kernel();
 	return 0;
 }