diff --git a/sound/core/init.c b/sound/core/init.c
index ed4a481..6b90871 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -46,7 +46,8 @@
 
 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 @@
 	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 @@
 			 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 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 @@
 	/* 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 */