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authorMauro Carvalho Chehab <mchehab@redhat.com>2008-11-20 10:30:26 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2008-11-20 18:12:02 -0200
commit818a557eeb9c16a9a2dc93df348b0ff68fbc487f (patch)
treed1ac8a7c8ad69f603100e13f5170525259e6385c /drivers/media
parentcce257109f534b4954a5d04aa4ba6905f4682f93 (diff)
V4L/DVB (9668): 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. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/video/em28xx/em28xx-video.c128
1 files changed, 75 insertions, 53 deletions
diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index c32fc7d24a4..90a11b5ac0b 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -73,6 +73,7 @@ MODULE_DESCRIPTION(DRIVER_DESC);
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 };
@@ -1519,7 +1520,7 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
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;
@@ -1535,10 +1536,11 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
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);
@@ -1547,10 +1549,9 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
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;
@@ -1584,7 +1585,6 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
sizeof(struct em28xx_buffer), fh);
mutex_unlock(&dev->lock);
- unlock_kernel();
return errCode;
}
@@ -1871,6 +1871,7 @@ int em28xx_register_extension(struct em28xx_ops *ops)
{
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) {
@@ -1879,6 +1880,7 @@ int em28xx_register_extension(struct em28xx_ops *ops)
}
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);
@@ -1887,6 +1889,7 @@ void em28xx_unregister_extension(struct em28xx_ops *ops)
{
struct em28xx *dev = NULL;
+ mutex_lock(&em28xx_devlist_mutex);
list_for_each_entry(dev, &em28xx_devlist, devlist) {
if (dev)
ops->fini(dev);
@@ -1896,6 +1899,7 @@ void em28xx_unregister_extension(struct em28xx_ops *ops)
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);
@@ -1921,6 +1925,60 @@ static struct video_device *em28xx_vdev_init(struct em28xx *dev,
}
+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
@@ -2000,50 +2058,6 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
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);
@@ -2070,8 +2084,14 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
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)) {
@@ -2081,11 +2101,13 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
}
}
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;
}