The patch number 9668 was added via Mauro Carvalho Chehab <[EMAIL PROTECTED]>
to http://linuxtv.org/hg/v4l-dvb master development tree.
Kernel patches in this development tree may be modified to be backward
compatible with older kernels. Compatibility modifications will be
removed before inclusion into the mainstream Kernel
If anyone has any objections, please let us know by sending a message to:
[EMAIL PROTECTED]
------
From: Mauro Carvalho Chehab <[EMAIL PROTECTED]>
em28xx: fix a race condition with hald
Newer versions of hald tries to open it to call QUERYCAP.
Due to the lack of a proper locking, it is possible to open the device
before it finishes initialization.
This patch adds a lock to avoid this risk, and to protect the list of
em28xx devices.
While here, remove the uneeded BKL lock.
Priority: high
Signed-off-by: Mauro Carvalho Chehab <[EMAIL PROTECTED]>
---
linux/drivers/media/video/em28xx/em28xx-video.c | 129 +++++++++-------
1 file changed, 76 insertions(+), 53 deletions(-)
diff -r fa01a2198f7f -r 207c91177b60
linux/drivers/media/video/em28xx/em28xx-video.c
--- a/linux/drivers/media/video/em28xx/em28xx-video.c Fri Nov 14 01:03:00
2008 +0000
+++ b/linux/drivers/media/video/em28xx/em28xx-video.c Thu Nov 20 11:30:26
2008 -0200
@@ -73,6 +73,7 @@ MODULE_LICENSE("GPL");
MODULE_LICENSE("GPL");
static LIST_HEAD(em28xx_devlist);
+static DEFINE_MUTEX(em28xx_devlist_mutex);
static unsigned int card[] = {[0 ... (EM28XX_MAXBOARDS - 1)] = UNSET };
static unsigned int video_nr[] = {[0 ... (EM28XX_MAXBOARDS - 1)] = UNSET };
@@ -1562,7 +1563,7 @@ static int em28xx_v4l2_open(struct inode
struct em28xx_fh *fh;
enum v4l2_buf_type fh_type = 0;
- lock_kernel();
+ mutex_lock(&em28xx_devlist_mutex);
list_for_each_entry(h, &em28xx_devlist, devlist) {
if (h->vdev->minor == minor) {
dev = h;
@@ -1578,10 +1579,11 @@ static int em28xx_v4l2_open(struct inode
dev = h;
}
}
- if (NULL == dev) {
- unlock_kernel();
+ mutex_unlock(&em28xx_devlist_mutex);
+ if (NULL == dev)
return -ENODEV;
- }
+
+ mutex_lock(&dev->lock);
em28xx_videodbg("open minor=%d type=%s users=%d\n",
minor, v4l2_type_names[fh_type], dev->users);
@@ -1590,6 +1592,7 @@ static int em28xx_v4l2_open(struct inode
errCode = em28xx_set_mode(dev, EM28XX_ANALOG_MODE);
if (errCode < 0) {
em28xx_errdev("Device locked on digital mode. Can't open
analog\n");
+ mutex_unlock(&dev->lock);
return -EBUSY;
}
#endif
@@ -1597,10 +1600,9 @@ static int em28xx_v4l2_open(struct inode
fh = kzalloc(sizeof(struct em28xx_fh), GFP_KERNEL);
if (!fh) {
em28xx_errdev("em28xx-video.c: Out of memory?!\n");
- unlock_kernel();
+ mutex_unlock(&dev->lock);
return -ENOMEM;
}
- mutex_lock(&dev->lock);
fh->dev = dev;
fh->radio = radio;
fh->type = fh_type;
@@ -1641,7 +1643,6 @@ static int em28xx_v4l2_open(struct inode
sizeof(struct em28xx_buffer), fh);
mutex_unlock(&dev->lock);
- unlock_kernel();
return errCode;
}
@@ -1939,6 +1940,7 @@ int em28xx_register_extension(struct em2
{
struct em28xx *dev = NULL;
+ mutex_lock(&em28xx_devlist_mutex);
mutex_lock(&em28xx_extension_devlist_lock);
list_add_tail(&ops->next, &em28xx_extension_devlist);
list_for_each_entry(dev, &em28xx_devlist, devlist) {
@@ -1947,6 +1949,7 @@ int em28xx_register_extension(struct em2
}
printk(KERN_INFO "Em28xx: Initialized (%s) extension\n", ops->name);
mutex_unlock(&em28xx_extension_devlist_lock);
+ mutex_unlock(&em28xx_devlist_mutex);
return 0;
}
EXPORT_SYMBOL(em28xx_register_extension);
@@ -1955,6 +1958,7 @@ void em28xx_unregister_extension(struct
{
struct em28xx *dev = NULL;
+ mutex_lock(&em28xx_devlist_mutex);
list_for_each_entry(dev, &em28xx_devlist, devlist) {
if (dev)
ops->fini(dev);
@@ -1964,6 +1968,7 @@ void em28xx_unregister_extension(struct
printk(KERN_INFO "Em28xx: Removed (%s) extension\n", ops->name);
list_del(&ops->next);
mutex_unlock(&em28xx_extension_devlist_lock);
+ mutex_unlock(&em28xx_devlist_mutex);
}
EXPORT_SYMBOL(em28xx_unregister_extension);
@@ -1988,6 +1993,60 @@ static struct video_device *em28xx_vdev_
return vfd;
}
+static int register_analog_devices(struct em28xx *dev)
+{
+ int ret;
+
+ /* allocate and fill video video_device struct */
+ dev->vdev = em28xx_vdev_init(dev, &em28xx_video_template, "video");
+ if (!dev->vdev) {
+ em28xx_errdev("cannot allocate video_device.\n");
+ return -ENODEV;
+ }
+
+ /* register v4l2 video video_device */
+ ret = video_register_device(dev->vdev, VFL_TYPE_GRABBER,
+ video_nr[dev->devno]);
+ if (ret) {
+ em28xx_errdev("unable to register video device (error=%i).\n",
+ ret);
+ return ret;
+ }
+
+ /* Allocate and fill vbi video_device struct */
+ dev->vbi_dev = em28xx_vdev_init(dev, &em28xx_video_template, "vbi");
+
+ /* register v4l2 vbi video_device */
+ ret = video_register_device(dev->vbi_dev, VFL_TYPE_VBI,
+ vbi_nr[dev->devno]);
+ if (ret < 0) {
+ em28xx_errdev("unable to register vbi device\n");
+ return ret;
+ }
+
+ if (em28xx_boards[dev->model].radio.type == EM28XX_RADIO) {
+ dev->radio_dev = em28xx_vdev_init(dev, &em28xx_radio_template,
"radio");
+ if (!dev->radio_dev) {
+ em28xx_errdev("cannot allocate video_device.\n");
+ return -ENODEV;
+ }
+ ret = video_register_device(dev->radio_dev, VFL_TYPE_RADIO,
+ radio_nr[dev->devno]);
+ if (ret < 0) {
+ em28xx_errdev("can't register radio device\n");
+ return ret;
+ }
+ em28xx_info("Registered radio device as /dev/radio%d\n",
+ dev->radio_dev->num);
+ }
+
+ em28xx_info("V4L2 device registered as /dev/video%d and /dev/vbi%d\n",
+ dev->vdev->num, dev->vbi_dev->num);
+
+ return 0;
+}
+
+
/*
* em28xx_init_dev()
* allocates and inits the device structs, registers i2c bus and v4l device
@@ -2066,50 +2125,6 @@ static int em28xx_init_dev(struct em28xx
return errCode;
}
- list_add_tail(&dev->devlist, &em28xx_devlist);
-
- /* allocate and fill video video_device struct */
- dev->vdev = em28xx_vdev_init(dev, &em28xx_video_template, "video");
- if (NULL == dev->vdev) {
- em28xx_errdev("cannot allocate video_device.\n");
- goto fail_unreg;
- }
-
- /* register v4l2 video video_device */
- retval = video_register_device(dev->vdev, VFL_TYPE_GRABBER,
- video_nr[dev->devno]);
- if (retval) {
- em28xx_errdev("unable to register video device (error=%i).\n",
- retval);
- goto fail_unreg;
- }
-
- /* Allocate and fill vbi video_device struct */
- dev->vbi_dev = em28xx_vdev_init(dev, &em28xx_video_template, "vbi");
- /* register v4l2 vbi video_device */
- if (video_register_device(dev->vbi_dev, VFL_TYPE_VBI,
- vbi_nr[dev->devno]) < 0) {
- em28xx_errdev("unable to register vbi device\n");
- retval = -ENODEV;
- goto fail_unreg;
- }
-
- if (em28xx_boards[dev->model].radio.type == EM28XX_RADIO) {
- dev->radio_dev = em28xx_vdev_init(dev, &em28xx_radio_template,
"radio");
- if (NULL == dev->radio_dev) {
- em28xx_errdev("cannot allocate video_device.\n");
- goto fail_unreg;
- }
- retval = video_register_device(dev->radio_dev, VFL_TYPE_RADIO,
- radio_nr[dev->devno]);
- if (retval < 0) {
- em28xx_errdev("can't register radio device\n");
- goto fail_unreg;
- }
- em28xx_info("Registered radio device as /dev/radio%d\n",
- dev->radio_dev->num);
- }
-
/* init video dma queues */
INIT_LIST_HEAD(&dev->vidq.active);
INIT_LIST_HEAD(&dev->vidq.queued);
@@ -2139,8 +2154,14 @@ static int em28xx_init_dev(struct em28xx
video_mux(dev, 0);
- em28xx_info("V4L2 device registered as /dev/video%d and /dev/vbi%d\n",
- dev->vdev->num, dev->vbi_dev->num);
+ mutex_lock(&em28xx_devlist_mutex);
+ list_add_tail(&dev->devlist, &em28xx_devlist);
+ retval = register_analog_devices(dev);
+ if (retval < 0) {
+ em28xx_release_resources(dev);
+ mutex_unlock(&em28xx_devlist_mutex);
+ goto fail_reg_devices;
+ }
mutex_lock(&em28xx_extension_devlist_lock);
if (!list_empty(&em28xx_extension_devlist)) {
@@ -2150,11 +2171,13 @@ static int em28xx_init_dev(struct em28xx
}
}
mutex_unlock(&em28xx_extension_devlist_lock);
+ mutex_unlock(&em28xx_devlist_mutex);
return 0;
fail_unreg:
em28xx_release_resources(dev);
+fail_reg_devices:
mutex_unlock(&dev->lock);
return retval;
}
---
Patch is available at:
http://linuxtv.org/hg/v4l-dvb/rev/207c91177b60b59f207aac34dbb6d438d7e71dd0
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