[PATCH] ieee1394: dv1394: sem2mutex conversion

Signed-off-by: Stefan Richter <[e-mail]> (not runtime-tested)
Signed-off-by: Ben Collins <[e-mail]>

drivers/ieee1394/dv1394-private.h

···
 	int dma_running;
 
 	/*
-	  3) the sleeping semaphore 'sem' - this is used from process context only,
+	  3) the sleeping mutex 'mtx' - this is used from process context only,
 	  to serialize various operations on the video_card. Even though only one
 	  open() is allowed, we still need to prevent multiple threads of execution
 	  from entering calls like read, write, ioctl, etc.
···
 	  I honestly can't think of a good reason to use dv1394 from several threads
 	  at once, but we need to serialize anyway to prevent oopses =).
 
-	  NOTE: if you need both spinlock and sem, take sem first to avoid deadlock!
+	  NOTE: if you need both spinlock and mtx, take mtx first to avoid deadlock!
 	 */
-	struct semaphore sem;
+	struct mutex mtx;
 
 	/* people waiting for buffer space, please form a line here... */
 	wait_queue_head_t waitq;

drivers/ieee1394/dv1394.c

···
 #include <linux/fs.h>
 #include <linux/poll.h>
 #include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/bitops.h>
 #include <asm/byteorder.h>
 #include <asm/atomic.h>
···
 
    Frame_prepare() must be called OUTSIDE the video->spinlock.
    However, frame_prepare() must still be serialized, so
-   it should be called WITH the video->sem taken.
+   it should be called WITH the video->mtx taken.
  */
 
 static void frame_prepare(struct video_card *video, unsigned int this_frame)
···
 	int retval = -EINVAL;
 
 	/* serialize mmap */
-	down(&video->sem);
+	mutex_lock(&video->mtx);
 
 	if ( ! video_card_initialized(video) ) {
 		retval = do_dv1394_init_default(video);
···
 
 	retval = dma_region_mmap(&video->dv_buf, file, vma);
 out:
-	up(&video->sem);
+	mutex_unlock(&video->mtx);
 	return retval;
 }
 
···
 
 	/* serialize this to prevent multi-threaded mayhem */
 	if (file->f_flags & O_NONBLOCK) {
-		if (down_trylock(&video->sem))
+		if (!mutex_trylock(&video->mtx))
 			return -EAGAIN;
 	} else {
-		if (down_interruptible(&video->sem))
+		if (mutex_lock_interruptible(&video->mtx))
 			return -ERESTARTSYS;
 	}
 
 	if ( !video_card_initialized(video) ) {
 		ret = do_dv1394_init_default(video);
 		if (ret) {
-			up(&video->sem);
+			mutex_unlock(&video->mtx);
 			return ret;
 		}
 	}
···
 
 	remove_wait_queue(&video->waitq, &wait);
 	set_current_state(TASK_RUNNING);
-	up(&video->sem);
+	mutex_unlock(&video->mtx);
 	return ret;
 }
 
···
 
 	/* serialize this to prevent multi-threaded mayhem */
 	if (file->f_flags & O_NONBLOCK) {
-		if (down_trylock(&video->sem))
+		if (!mutex_trylock(&video->mtx))
 			return -EAGAIN;
 	} else {
-		if (down_interruptible(&video->sem))
+		if (mutex_lock_interruptible(&video->mtx))
 			return -ERESTARTSYS;
 	}
 
 	if ( !video_card_initialized(video) ) {
 		ret = do_dv1394_init_default(video);
 		if (ret) {
-			up(&video->sem);
+			mutex_unlock(&video->mtx);
 			return ret;
 		}
 		video->continuity_counter = -1;
···
 
 	remove_wait_queue(&video->waitq, &wait);
 	set_current_state(TASK_RUNNING);
-	up(&video->sem);
+	mutex_unlock(&video->mtx);
 	return ret;
 }
 
···
 
 	/* serialize this to prevent multi-threaded mayhem */
 	if (file->f_flags & O_NONBLOCK) {
-		if (down_trylock(&video->sem)) {
+		if (!mutex_trylock(&video->mtx)) {
 			unlock_kernel();
 			return -EAGAIN;
 		}
 	} else {
-		if (down_interruptible(&video->sem)) {
+		if (mutex_lock_interruptible(&video->mtx)) {
 			unlock_kernel();
 			return -ERESTARTSYS;
 		}
···
 	}
 
  out:
-	up(&video->sem);
+	mutex_unlock(&video->mtx);
 	unlock_kernel();
 	return ret;
 }
···
 	clear_bit(0, &video->open);
 	spin_lock_init(&video->spinlock);
 	video->dma_running = 0;
-	init_MUTEX(&video->sem);
+	mutex_init(&video->mtx);
 	init_waitqueue_head(&video->waitq);
 	video->fasync = NULL;