[PATCH 04/12] media: autoconvert trivial BKL users to private mutex

From: Arnd Bergmann
Date: Sun Jul 11 2010 - 17:19:40 EST

All these files use the big kernel lock in a trivial
way to serialize their private file operations,
typically resulting from an earlier semi-automatic
pushdown from VFS.

None of these drivers appears to want to lock against
other code, and they all use the BKL as the top-level
lock in their file operations, meaning that there
is no lock-order inversion problem.

Consequently, we can remove the BKL completely,
replacing it with a per-file mutex in every case.
Using a scripted approach means we can avoid
typos.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
if grep -q 'include.*linux.mutex.h' ${file} ; then
sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
else
sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
fi
sed -i ${file} \
-e "/^#include.*linux.mutex.h/,$ {
1,/^\(static\|int\|long\)/ {
/^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }" \
-e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
-e '/[ ]*cycle_kernel_lock();/d'
else
sed -i -e '/include.*\<smp_lock.h\>/d' ${file} \
-e '/cycle_kernel_lock()/d'
fi

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx>
Cc: linux-media@xxxxxxxxxxxxxxx
---
drivers/media/dvb/bt8xx/dst_ca.c | 7 ++++---
drivers/media/video/cx88/cx88-blackbird.c | 13 +++++++------
drivers/media/video/dabusb.c | 18 +++++++++---------
drivers/media/video/se401.c | 9 +++++----
drivers/media/video/stradis.c | 9 +++++----
drivers/media/video/usbvideo/vicam.c | 14 +++++++-------
6 files changed, 37 insertions(+), 33 deletions(-)

diff --git a/drivers/media/dvb/bt8xx/dst_ca.c b/drivers/media/dvb/bt8xx/dst_ca.c
index 770243c..f0c59c0 100644
--- a/drivers/media/dvb/bt8xx/dst_ca.c
+++ b/drivers/media/dvb/bt8xx/dst_ca.c
@@ -22,7 +22,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/string.h>
#include <linux/dvb/ca.h>
#include "dvbdev.h"
@@ -52,6 +52,7 @@
} while(0)


+static DEFINE_MUTEX(dst_ca_mutex);
static unsigned int verbose = 5;
module_param(verbose, int, 0644);
MODULE_PARM_DESC(verbose, "verbose startup messages, default is 1 (yes)");
@@ -564,7 +565,7 @@ static long dst_ca_ioctl(struct file *file, unsigned int cmd, unsigned long ioct
void __user *arg = (void __user *)ioctl_arg;
int result = 0;

- lock_kernel();
+ mutex_lock(&dst_ca_mutex);
dvbdev = (struct dvb_device *)file->private_data;
state = (struct dst_state *)dvbdev->priv;
p_ca_message = kmalloc(sizeof (struct ca_msg), GFP_KERNEL);
@@ -652,7 +653,7 @@ static long dst_ca_ioctl(struct file *file, unsigned int cmd, unsigned long ioct
kfree (p_ca_slot_info);
kfree (p_ca_caps);

- unlock_kernel();
+ mutex_unlock(&dst_ca_mutex);
return result;
}

diff --git a/drivers/media/video/cx88/cx88-blackbird.c b/drivers/media/video/cx88/cx88-blackbird.c
index e46e1ce..6bb59f1 100644
--- a/drivers/media/video/cx88/cx88-blackbird.c
+++ b/drivers/media/video/cx88/cx88-blackbird.c
@@ -33,7 +33,7 @@
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/firmware.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/cx2341x.h>
@@ -44,6 +44,7 @@ MODULE_DESCRIPTION("driver for cx2388x/cx23416 based mpeg encoder cards");
MODULE_AUTHOR("Jelle Foks <jelle@xxxxxxx>, Gerd Knorr <kraxel@xxxxxxxxxxx> [SuSE Labs]");
MODULE_LICENSE("GPL");

+static DEFINE_MUTEX(mpeg_mutex);
static unsigned int mpegbufs = 32;
module_param(mpegbufs,int,0644);
MODULE_PARM_DESC(mpegbufs,"number of mpeg buffers, range 2-32");
@@ -1057,7 +1058,7 @@ static int mpeg_open(struct file *file)

dprintk( 1, "%s\n", __func__);

- lock_kernel();
+ mutex_lock(&mpeg_mutex);

/* Make sure we can acquire the hardware */
drv = cx8802_get_driver(dev, CX88_MPEG_BLACKBIRD);
@@ -1065,7 +1066,7 @@ static int mpeg_open(struct file *file)
err = drv->request_acquire(drv);
if(err != 0) {
dprintk(1,"%s: Unable to acquire hardware, %d\n", __func__, err);
- unlock_kernel();
+ mutex_unlock(&mpeg_mutex);
return err;
}
}
@@ -1073,7 +1074,7 @@ static int mpeg_open(struct file *file)
if (!atomic_read(&dev->core->mpeg_users) && blackbird_initialize_codec(dev) < 0) {
if (drv)
drv->request_release(drv);
- unlock_kernel();
+ mutex_unlock(&mpeg_mutex);
return -EINVAL;
}
dprintk(1, "open dev=%s\n", video_device_node_name(vdev));
@@ -1083,7 +1084,7 @@ static int mpeg_open(struct file *file)
if (NULL == fh) {
if (drv)
drv->request_release(drv);
- unlock_kernel();
+ mutex_unlock(&mpeg_mutex);
return -ENOMEM;
}
file->private_data = fh;
@@ -1099,7 +1100,7 @@ static int mpeg_open(struct file *file)
/* FIXME: locking against other video device */
cx88_set_scale(dev->core, dev->width, dev->height,
fh->mpegq.field);
- unlock_kernel();
+ mutex_unlock(&mpeg_mutex);

atomic_inc(&dev->core->mpeg_users);

diff --git a/drivers/media/video/dabusb.c b/drivers/media/video/dabusb.c
index 0f50508..716d0ee 100644
--- a/drivers/media/video/dabusb.c
+++ b/drivers/media/video/dabusb.c
@@ -32,7 +32,6 @@
#include <linux/list.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>
@@ -61,6 +60,7 @@

/*-------------------------------------------------------------------*/

+static DEFINE_MUTEX(dabusb_mutex);
static dabusb_t dabusb[NRDABUSB];
static int buffers = 256;
static struct usb_driver dabusb_driver;
@@ -621,7 +621,7 @@ static int dabusb_open (struct inode *inode, struct file *file)
if (devnum < DABUSB_MINOR || devnum >= (DABUSB_MINOR + NRDABUSB))
return -EIO;

- lock_kernel();
+ mutex_lock(&dabusb_mutex);
s = &dabusb[devnum - DABUSB_MINOR];

dbg("dabusb_open");
@@ -636,7 +636,7 @@ static int dabusb_open (struct inode *inode, struct file *file)
msleep_interruptible(500);

if (signal_pending (current)) {
- unlock_kernel();
+ mutex_unlock(&dabusb_mutex);
return -EAGAIN;
}
mutex_lock(&s->mutex);
@@ -644,7 +644,7 @@ static int dabusb_open (struct inode *inode, struct file *file)
if (usb_set_interface (s->usbdev, _DABUSB_IF, 1) < 0) {
mutex_unlock(&s->mutex);
dev_err(&s->usbdev->dev, "set_interface failed\n");
- unlock_kernel();
+ mutex_unlock(&dabusb_mutex);
return -EINVAL;
}
s->opened = 1;
@@ -654,7 +654,7 @@ static int dabusb_open (struct inode *inode, struct file *file)
file->private_data = s;

r = nonseekable_open(inode, file);
- unlock_kernel();
+ mutex_unlock(&dabusb_mutex);
return r;
}

@@ -689,9 +689,9 @@ static long dabusb_ioctl (struct file *file, unsigned int cmd, unsigned long arg

dbg("dabusb_ioctl");

- lock_kernel();
+ mutex_lock(&dabusb_mutex);
if (s->remove_pending) {
- unlock_kernel();
+ mutex_unlock(&dabusb_mutex);
return -EIO;
}

@@ -699,7 +699,7 @@ static long dabusb_ioctl (struct file *file, unsigned int cmd, unsigned long arg

if (!s->usbdev) {
mutex_unlock(&s->mutex);
- unlock_kernel();
+ mutex_unlock(&dabusb_mutex);
return -EIO;
}

@@ -740,7 +740,7 @@ static long dabusb_ioctl (struct file *file, unsigned int cmd, unsigned long arg
break;
}
mutex_unlock(&s->mutex);
- unlock_kernel();
+ mutex_unlock(&dabusb_mutex);
return ret;
}

diff --git a/drivers/media/video/se401.c b/drivers/media/video/se401.c
index 41d0166..87cfdd9 100644
--- a/drivers/media/video/se401.c
+++ b/drivers/media/video/se401.c
@@ -31,11 +31,12 @@ static const char version[] = "0.24";
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/pagemap.h>
#include <linux/usb.h>
#include "se401.h"

+static DEFINE_MUTEX(se401_mutex);
static int flickerless;
static int video_nr = -1;

@@ -951,9 +952,9 @@ static int se401_open(struct file *file)
struct usb_se401 *se401 = (struct usb_se401 *)dev;
int err = 0;

- lock_kernel();
+ mutex_lock(&se401_mutex);
if (se401->user) {
- unlock_kernel();
+ mutex_unlock(&se401_mutex);
return -EBUSY;
}
se401->fbuf = rvmalloc(se401->maxframesize * SE401_NUMFRAMES);
@@ -962,7 +963,7 @@ static int se401_open(struct file *file)
else
err = -ENOMEM;
se401->user = !err;
- unlock_kernel();
+ mutex_unlock(&se401_mutex);

return err;
}
diff --git a/drivers/media/video/stradis.c b/drivers/media/video/stradis.c
index a057824..844ef47 100644
--- a/drivers/media/video/stradis.c
+++ b/drivers/media/video/stradis.c
@@ -26,7 +26,7 @@
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/poll.h>
@@ -58,6 +58,7 @@

#define SAA7146_MAX 6

+static DEFINE_MUTEX(saa_mutex);
static struct saa7146 saa7146s[SAA7146_MAX];

static int saa_num; /* number of SAA7146s in use */
@@ -1883,16 +1884,16 @@ static int saa_open(struct file *file)
struct video_device *vdev = video_devdata(file);
struct saa7146 *saa = container_of(vdev, struct saa7146, video_dev);

- lock_kernel();
+ mutex_lock(&saa_mutex);
file->private_data = saa;

saa->user++;
if (saa->user > 1) {
- unlock_kernel();
+ mutex_unlock(&saa_mutex);
return 0; /* device open already, don't reset */
}
saa->writemode = VID_WRITE_MPEG_VID; /* default to video */
- unlock_kernel();
+ mutex_unlock(&saa_mutex);
return 0;
}

diff --git a/drivers/media/video/usbvideo/vicam.c b/drivers/media/video/usbvideo/vicam.c
index 6030410..a87b5b4 100644
--- a/drivers/media/video/usbvideo/vicam.c
+++ b/drivers/media/video/usbvideo/vicam.c
@@ -43,7 +43,6 @@
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include <linux/firmware.h>
#include <linux/ihex.h>
@@ -81,6 +80,7 @@
* in the future.
*
*/
+static DEFINE_MUTEX(vicam_mutex);
static void *rvmalloc(unsigned long size)
{
void *mem;
@@ -488,24 +488,24 @@ vicam_open(struct file *file)
* rely on this fact forever.
*/

- lock_kernel();
+ mutex_lock(&vicam_mutex);
if (cam->open_count > 0) {
printk(KERN_INFO
"vicam_open called on already opened camera");
- unlock_kernel();
+ mutex_unlock(&vicam_mutex);
return -EBUSY;
}

cam->raw_image = kmalloc(VICAM_MAX_READ_SIZE, GFP_KERNEL);
if (!cam->raw_image) {
- unlock_kernel();
+ mutex_unlock(&vicam_mutex);
return -ENOMEM;
}

cam->framebuf = rvmalloc(VICAM_MAX_FRAME_SIZE * VICAM_FRAMES);
if (!cam->framebuf) {
kfree(cam->raw_image);
- unlock_kernel();
+ mutex_unlock(&vicam_mutex);
return -ENOMEM;
}

@@ -513,7 +513,7 @@ vicam_open(struct file *file)
if (!cam->cntrlbuf) {
kfree(cam->raw_image);
rvfree(cam->framebuf, VICAM_MAX_FRAME_SIZE * VICAM_FRAMES);
- unlock_kernel();
+ mutex_unlock(&vicam_mutex);
return -ENOMEM;
}

@@ -531,7 +531,7 @@ vicam_open(struct file *file)
cam->open_count++;

file->private_data = cam;
- unlock_kernel();
+ mutex_unlock(&vicam_mutex);

return 0;
}
--
1.7.1

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