[PATCH] dv1394: remove BKL contention

From: Stefan Richter
Date: Fri Oct 20 2006 - 15:02:39 EST


Purges the one remaining call to lock_kernel() from the 1394 subsystem.

Signed-off-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
---
Index: linux/drivers/ieee1394/dv1394.c
===================================================================
--- linux.orig/drivers/ieee1394/dv1394.c 2006-10-20 20:54:33.000000000 +0200
+++ linux/drivers/ieee1394/dv1394.c 2006-10-20 20:55:03.000000000 +0200
@@ -1536,27 +1536,20 @@ static ssize_t dv1394_read(struct file *

static long dv1394_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
- struct video_card *video;
+ struct video_card *video = file_to_video_card(file);
unsigned long flags;
int ret = -EINVAL;
void __user *argp = (void __user *)arg;

DECLARE_WAITQUEUE(wait, current);

- lock_kernel();
- video = file_to_video_card(file);
-
/* serialize this to prevent multi-threaded mayhem */
if (file->f_flags & O_NONBLOCK) {
- if (!mutex_trylock(&video->mtx)) {
- unlock_kernel();
+ if (!mutex_trylock(&video->mtx))
return -EAGAIN;
- }
} else {
- if (mutex_lock_interruptible(&video->mtx)) {
- unlock_kernel();
+ if (mutex_lock_interruptible(&video->mtx))
return -ERESTARTSYS;
- }
}

switch(cmd)
@@ -1780,7 +1773,6 @@ static long dv1394_ioctl(struct file *fi

out:
mutex_unlock(&video->mtx);
- unlock_kernel();
return ret;
}



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