Use mutex instead of semaphore in CAPI 2.0 driver

The CAPI 2.0 driver uses a semaphore as mutex.  Use the mutex API instead of
the (binary) semaphore.

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Acked-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/isdn/capi/kcapi.c

@@ -258,7 +258,7 @@ static void recv_handler(struct work_struct *work)
 	if ((!ap) || (ap->release_in_progress))
 		return;
 
-	down(&ap->recv_sem);
+	mutex_lock(&ap->recv_mtx);
 	while ((skb = skb_dequeue(&ap->recv_queue))) {
 		if (CAPIMSG_CMD(skb->data) == CAPI_DATA_B3_IND)
 			ap->nrecvdatapkt++;
@@ -267,7 +267,7 @@ static void recv_handler(struct work_struct *work)
 
 		ap->recv_message(ap, skb);
 	}
-	up(&ap->recv_sem);
+	mutex_unlock(&ap->recv_mtx);
 }
 
 void capi_ctr_handle_message(struct capi_ctr * card, u16 appl, struct sk_buff *skb)
@@ -547,7 +547,7 @@ u16 capi20_register(struct capi20_appl *ap)
 	ap->nsentctlpkt = 0;
 	ap->nsentdatapkt = 0;
 	ap->callback = NULL;
-	init_MUTEX(&ap->recv_sem);
+	mutex_init(&ap->recv_mtx);
 	skb_queue_head_init(&ap->recv_queue);
 	INIT_WORK(&ap->recv_work, recv_handler);
 	ap->release_in_progress = 0;

include/linux/kernelcapi.h

@@ -64,7 +64,7 @@ struct capi20_appl {
 	unsigned long nrecvdatapkt;
 	unsigned long nsentctlpkt;
 	unsigned long nsentdatapkt;
-	struct semaphore recv_sem;
+	struct mutex recv_mtx;
 	struct sk_buff_head recv_queue;
 	struct work_struct recv_work;
 	int release_in_progress;