[ALSA] cleanup and error reporting for sound/core/init.c

Make the control flow clear with indentation, adds some comments
and improves error reporting.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

diff --git a/sound/core/init.c b/sound/core/init.c
index a4cc6b1..db61037 100644 (file)
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -114,22 +114,28 @@ struct snd_card *snd_card_new(int idx, const char *xid,
        if (idx < 0) {
                int idx2;
                for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
+                       /* idx == -1 == 0xffff means: take any free slot */
                        if (~snd_cards_lock & idx & 1<<idx2) {
                                idx = idx2;
                                if (idx >= snd_ecards_limit)
                                        snd_ecards_limit = idx + 1;
                                break;
                        }
-       } else if (idx < snd_ecards_limit) {
-               if (snd_cards_lock & (1 << idx))
-                       err = -ENODEV;  /* invalid */
-       } else if (idx < SNDRV_CARDS)
-               snd_ecards_limit = idx + 1; /* increase the limit */
-       else
-               err = -ENODEV;
+       } else {
+                if (idx < snd_ecards_limit) {
+                       if (snd_cards_lock & (1 << idx))
+                               err = -EBUSY;   /* invalid */
+               } else {
+                       if (idx < SNDRV_CARDS)
+                               snd_ecards_limit = idx + 1; /* increase the limit */
+                       else
+                               err = -ENODEV;
+               }
+       }
        if (idx < 0 || err < 0) {
                mutex_unlock(&snd_card_mutex);
-               snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i)\n", idx, snd_ecards_limit - 1);
+               snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i), error: %d\n",
+                        idx, snd_ecards_limit - 1, err);
                goto __error;
        }
        snd_cards_lock |= 1 << idx;             /* lock it */