[media] v4l: kill the BKL

All of the hard problems for BKL removal appear to be solved in the
v4l-dvb/master tree. This removes the BKL from the various open
functions that do not need it, or only use it to protect an
open count.

The zoran driver is nontrivial in this regard, so I introduce
a new mutex that locks both the open/release and the ioctl
functions. Someone with access to the hardware can probably
improve that by using the existing lock in all cases.

Finally, all drivers that still use the locked version of the
ioctl function now get called under a new mutex instead of
the BKL.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 23 insertions, 6 deletions

diff --git a/drivers/media/video/zoran/zoran.h b/drivers/media/video/zoran/zoran.h
index 37fe161..27f0555 100644
--- a/drivers/media/video/zoran/zoran.h
+++ b/drivers/media/video/zoran/zoran.h
@@ -388,6 +388,7 @@ struct zoran {
 	struct videocodec *vfe;	/* video front end */
 
 	struct mutex resource_lock;	/* prevent evil stuff */
+	struct mutex other_lock;	/* please merge with above */
 
 	u8 initialized;		/* flag if zoran has been correctly initialized */
 	int user;		/* number of current users */
diff --git a/drivers/media/video/zoran/zoran_card.c b/drivers/media/video/zoran/zoran_card.c
index 0aac376..7e6d624 100644
--- a/drivers/media/video/zoran/zoran_card.c
+++ b/drivers/media/video/zoran/zoran_card.c
@@ -1227,6 +1227,7 @@ static int __devinit zoran_probe(struct pci_dev *pdev,
 	snprintf(ZR_DEVNAME(zr), sizeof(ZR_DEVNAME(zr)), "MJPEG[%u]", zr->id);
 	spin_lock_init(&zr->spinlock);
 	mutex_init(&zr->resource_lock);
+	mutex_init(&zr->other_lock);
 	if (pci_enable_device(pdev))
 		goto zr_unreg;
 	pci_read_config_byte(zr->pci_dev, PCI_CLASS_REVISION, &zr->revision);
diff --git a/drivers/media/video/zoran/zoran_driver.c b/drivers/media/video/zoran/zoran_driver.c
index 401082b..67a52e8 100644
--- a/drivers/media/video/zoran/zoran_driver.c
+++ b/drivers/media/video/zoran/zoran_driver.c
@@ -49,7 +49,6 @@
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/pci.h>
 #include <linux/vmalloc.h>
 #include <linux/wait.h>
@@ -913,7 +912,7 @@ static int zoran_open(struct file *file)
 	dprintk(2, KERN_INFO "%s: %s(%s, pid=[%d]), users(-)=%d\n",
 		ZR_DEVNAME(zr), __func__, current->comm, task_pid_nr(current), zr->user + 1);
 
-	lock_kernel();
+	mutex_lock(&zr->other_lock);
 
 	if (zr->user >= 2048) {
 		dprintk(1, KERN_ERR "%s: too many users (%d) on device\n",
@@ -963,14 +962,14 @@ static int zoran_open(struct file *file)
 	file->private_data = fh;
 	fh->zr = zr;
 	zoran_open_init_session(fh);
-	unlock_kernel();
+	mutex_unlock(&zr->other_lock);
 
 	return 0;
 
 fail_fh:
 	kfree(fh);
 fail_unlock:
-	unlock_kernel();
+	mutex_unlock(&zr->other_lock);
 
 	dprintk(2, KERN_INFO "%s: open failed (%d), users(-)=%d\n",
 		ZR_DEVNAME(zr), res, zr->user);
@@ -989,7 +988,7 @@ zoran_close(struct file  *file)
 
 	/* kernel locks (fs/device.c), so don't do that ourselves
 	 * (prevents deadlocks) */
-	/*mutex_lock(&zr->resource_lock);*/
+	mutex_lock(&zr->other_lock);
 
 	zoran_close_end_session(fh);
 
@@ -1023,6 +1022,7 @@ zoran_close(struct file  *file)
 			encoder_call(zr, video, s_routing, 2, 0, 0);
 		}
 	}
+	mutex_unlock(&zr->other_lock);
 
 	file->private_data = NULL;
 	kfree(fh->overlay_mask);
@@ -3370,11 +3370,26 @@ static const struct v4l2_ioctl_ops zoran_ioctl_ops = {
 #endif
 };
 
+/* please use zr->resource_lock consistently and kill this wrapper */
+static long zoran_ioctl(struct file *file, unsigned int cmd,
+			unsigned long arg)
+{
+	struct zoran_fh *fh = file->private_data;
+	struct zoran *zr = fh->zr;
+	int ret;
+
+	mutex_lock(&zr->other_lock);
+	ret = video_ioctl2(file, cmd, arg);
+	mutex_unlock(&zr->other_lock);
+
+	return ret;
+}
+
 static const struct v4l2_file_operations zoran_fops = {
 	.owner = THIS_MODULE,
 	.open = zoran_open,
 	.release = zoran_close,
-	.ioctl = video_ioctl2,
+	.unlocked_ioctl = zoran_ioctl,
 	.read = zoran_read,
 	.write = zoran_write,
 	.mmap = zoran_mmap,