ALSA: Add kconfig to specify the max card numbers

Currently ALSA supports up to 32 card instances when the dynamic minor
is used.  While 32 cards are usually big enough for normal use cases,
there are sometimes weird requirements with more card support.

Actually, this limitation, 32, comes from the index option, where you
can pass the bit mask to assign the card.  Other than that, we can
actually give more cards up to the minor number limits (currently 256,
which can be extended more, too).

This patch adds a new Kconfig to specify the max card numbers, and
changes a few places to accept more than 32 cards.

The only incompatibility with high card numbers would be the handling
of index option.  The index option can be still used to pass the
bitmask for card assignments, but this works only up to 32 slots.
More than 32, no bitmask style option is available but only a single
slot can be specified via index option.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/sound/core.h b/include/sound/core.h
index 5bfe5136441c748de80c27992c94d6d60deb96bc..c586617cfa0dffaa2cdce5e548f78fed28e1f63e 100644 (file)
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -30,7 +30,7 @@
 
 /* number of supported soundcards */
 #ifdef CONFIG_SND_DYNAMIC_MINORS
-#define SNDRV_CARDS 32
+#define SNDRV_CARDS CONFIG_SND_MAX_CARDS
 #else
 #define SNDRV_CARDS 8          /* don't change - minor numbers */
 #endif

diff --git a/sound/core/Kconfig b/sound/core/Kconfig
index b413ed05e74deae78fbd97809c99f0fd68f1ee46..c0c2f57a0d6f332b6143c3eaa6850921c1dde485 100644 (file)
--- a/sound/core/Kconfig
+++ b/sound/core/Kconfig
@@ -157,6 +157,15 @@ config SND_DYNAMIC_MINORS
 
          If you are unsure about this, say N here.
 
+config SND_MAX_CARDS
+       int "Max number of sound cards"
+       range 4 256
+       default 32
+       depends on SND_DYNAMIC_MINORS
+       help
+         Specify the max number of sound cards that can be assigned
+         on a single machine.
+
 config SND_SUPPORT_OLD_API
        bool "Support old ALSA API"
        default y

diff --git a/sound/core/init.c b/sound/core/init.c
index ed4a4811b6a158a2f69cc9332219f9de6c568e4c..6b9087115da24806e8aba244127ac8ec3a4e93f8 100644 (file)
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -46,7 +46,8 @@ static LIST_HEAD(shutdown_files);
 
 static const struct file_operations snd_shutdown_f_ops;
 
-static unsigned int snd_cards_lock;    /* locked for registering/using */
+/* locked for registering/using */
+static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
 struct snd_card *snd_cards[SNDRV_CARDS];
 EXPORT_SYMBOL(snd_cards);
 
@@ -167,29 +168,35 @@ int snd_card_create(int idx, const char *xid,
        err = 0;
        mutex_lock(&snd_card_mutex);
        if (idx < 0) {
-               for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
+               for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++) {
                        /* idx == -1 == 0xffff means: take any free slot */
-                       if (~snd_cards_lock & idx & 1<<idx2) {
+                       if (idx2 < sizeof(int) && !(idx & (1U << idx2)))
+                               continue;
+                       if (!test_bit(idx2, snd_cards_lock)) {
                                if (module_slot_match(module, idx2)) {
                                        idx = idx2;
                                        break;
                                }
                        }
+               }
        }
        if (idx < 0) {
-               for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
+               for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++) {
                        /* idx == -1 == 0xffff means: take any free slot */
-                       if (~snd_cards_lock & idx & 1<<idx2) {
+                       if (idx2 < sizeof(int) && !(idx & (1U << idx2)))
+                               continue;
+                       if (!test_bit(idx2, snd_cards_lock)) {
                                if (!slots[idx2] || !*slots[idx2]) {
                                        idx = idx2;
                                        break;
                                }
                        }
+               }
        }
        if (idx < 0)
                err = -ENODEV;
        else if (idx < snd_ecards_limit) {
-               if (snd_cards_lock & (1 << idx))
+               if (test_bit(idx, snd_cards_lock))
                        err = -EBUSY;   /* invalid */
        } else if (idx >= SNDRV_CARDS)
                err = -ENODEV;
@@ -199,7 +206,7 @@ int snd_card_create(int idx, const char *xid,
                         idx, snd_ecards_limit - 1, err);
                goto __error;
        }
-       snd_cards_lock |= 1 << idx;             /* lock it */
+       set_bit(idx, snd_cards_lock);           /* lock it */
        if (idx >= snd_ecards_limit)
                snd_ecards_limit = idx + 1; /* increase the limit */
        mutex_unlock(&snd_card_mutex);
@@ -249,7 +256,7 @@ int snd_card_locked(int card)
        int locked;
 
        mutex_lock(&snd_card_mutex);
-       locked = snd_cards_lock & (1 << card);
+       locked = test_bit(card, snd_cards_lock);
        mutex_unlock(&snd_card_mutex);
        return locked;
 }
@@ -361,7 +368,7 @@ int snd_card_disconnect(struct snd_card *card)
        /* phase 1: disable fops (user space) operations for ALSA API */
        mutex_lock(&snd_card_mutex);
        snd_cards[card->number] = NULL;
-       snd_cards_lock &= ~(1 << card->number);
+       clear_bit(card->number, snd_cards_lock);
        mutex_unlock(&snd_card_mutex);
        
        /* phase 2: replace file->f_op with special dummy operations */