2 files changed, 25 insertions, 9 deletions

diff --git a/sound/core/Kconfig b/sound/core/Kconfig
index b413ed05e74d..c0c2f57a0d6f 100644
--- 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 ed4a4811b6a1..6b9087115da2 100644
--- 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 */