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Diffstat (limited to 'drivers/media/video/sn9c102/sn9c102_core.c')
-rw-r--r--drivers/media/video/sn9c102/sn9c102_core.c173
1 files changed, 103 insertions, 70 deletions
diff --git a/drivers/media/video/sn9c102/sn9c102_core.c b/drivers/media/video/sn9c102/sn9c102_core.c
index 74a204f8ebc8..36d8a455e0ec 100644
--- a/drivers/media/video/sn9c102/sn9c102_core.c
+++ b/drivers/media/video/sn9c102/sn9c102_core.c
@@ -48,8 +48,8 @@
#define SN9C102_MODULE_AUTHOR "(C) 2004-2007 Luca Risolia"
#define SN9C102_AUTHOR_EMAIL "<luca.risolia@studio.unibo.it>"
#define SN9C102_MODULE_LICENSE "GPL"
-#define SN9C102_MODULE_VERSION "1:1.44"
-#define SN9C102_MODULE_VERSION_CODE KERNEL_VERSION(1, 1, 44)
+#define SN9C102_MODULE_VERSION "1:1.47"
+#define SN9C102_MODULE_VERSION_CODE KERNEL_VERSION(1, 1, 47)
/*****************************************************************************/
@@ -64,9 +64,10 @@ MODULE_LICENSE(SN9C102_MODULE_LICENSE);
static short video_nr[] = {[0 ... SN9C102_MAX_DEVICES-1] = -1};
module_param_array(video_nr, short, NULL, 0444);
MODULE_PARM_DESC(video_nr,
- "\n<-1|n[,...]> Specify V4L2 minor mode number."
- "\n -1 = use next available (default)"
- "\n n = use minor number n (integer >= 0)"
+ " <-1|n[,...]>"
+ "\nSpecify V4L2 minor mode number."
+ "\n-1 = use next available (default)"
+ "\n n = use minor number n (integer >= 0)"
"\nYou can specify up to "__MODULE_STRING(SN9C102_MAX_DEVICES)
" cameras this way."
"\nFor example:"
@@ -79,13 +80,14 @@ static short force_munmap[] = {[0 ... SN9C102_MAX_DEVICES-1] =
SN9C102_FORCE_MUNMAP};
module_param_array(force_munmap, bool, NULL, 0444);
MODULE_PARM_DESC(force_munmap,
- "\n<0|1[,...]> Force the application to unmap previously"
+ " <0|1[,...]>"
+ "\nForce the application to unmap previously"
"\nmapped buffer memory before calling any VIDIOC_S_CROP or"
"\nVIDIOC_S_FMT ioctl's. Not all the applications support"
"\nthis feature. This parameter is specific for each"
"\ndetected camera."
- "\n 0 = do not force memory unmapping"
- "\n 1 = force memory unmapping (save memory)"
+ "\n0 = do not force memory unmapping"
+ "\n1 = force memory unmapping (save memory)"
"\nDefault value is "__MODULE_STRING(SN9C102_FORCE_MUNMAP)"."
"\n");
@@ -93,7 +95,8 @@ static unsigned int frame_timeout[] = {[0 ... SN9C102_MAX_DEVICES-1] =
SN9C102_FRAME_TIMEOUT};
module_param_array(frame_timeout, uint, NULL, 0644);
MODULE_PARM_DESC(frame_timeout,
- "\n<0|n[,...]> Timeout for a video frame in seconds before"
+ " <0|n[,...]>"
+ "\nTimeout for a video frame in seconds before"
"\nreturning an I/O error; 0 for infinity."
"\nThis parameter is specific for each detected camera."
"\nDefault value is "__MODULE_STRING(SN9C102_FRAME_TIMEOUT)"."
@@ -103,7 +106,8 @@ MODULE_PARM_DESC(frame_timeout,
static unsigned short debug = SN9C102_DEBUG_LEVEL;
module_param(debug, ushort, 0644);
MODULE_PARM_DESC(debug,
- "\n<n> Debugging information level, from 0 to 3:"
+ " <n>"
+ "\nDebugging information level, from 0 to 3:"
"\n0 = none (use carefully)"
"\n1 = critical errors"
"\n2 = significant informations"
@@ -1616,7 +1620,8 @@ static int sn9c102_init(struct sn9c102_device* cam)
int err = 0;
if (!(cam->state & DEV_INITIALIZED)) {
- init_waitqueue_head(&cam->open);
+ mutex_init(&cam->open_mutex);
+ init_waitqueue_head(&cam->wait_open);
qctrl = s->qctrl;
rect = &(s->cropcap.defrect);
} else { /* use current values */
@@ -1706,21 +1711,27 @@ static int sn9c102_init(struct sn9c102_device* cam)
return 0;
}
+/*****************************************************************************/
-static void sn9c102_release_resources(struct sn9c102_device* cam)
+static void sn9c102_release_resources(struct kref *kref)
{
+ struct sn9c102_device *cam;
+
mutex_lock(&sn9c102_sysfs_lock);
+ cam = container_of(kref, struct sn9c102_device, kref);
+
DBG(2, "V4L2 device /dev/video%d deregistered", cam->v4ldev->minor);
video_set_drvdata(cam->v4ldev, NULL);
video_unregister_device(cam->v4ldev);
+ usb_put_dev(cam->usbdev);
+ kfree(cam->control_buffer);
+ kfree(cam);
mutex_unlock(&sn9c102_sysfs_lock);
- kfree(cam->control_buffer);
}
-/*****************************************************************************/
static int sn9c102_open(struct inode* inode, struct file* filp)
{
@@ -1728,43 +1739,78 @@ static int sn9c102_open(struct inode* inode, struct file* filp)
int err = 0;
/*
- This is the only safe way to prevent race conditions with
- disconnect
+ A read_trylock() in open() is the only safe way to prevent race
+ conditions with disconnect(), one close() and multiple (not
+ necessarily simultaneous) attempts to open(). For example, it
+ prevents from waiting for a second access, while the device
+ structure is being deallocated, after a possible disconnect() and
+ during a following close() holding the write lock: given that, after
+ this deallocation, no access will be possible anymore, using the
+ non-trylock version would have let open() gain the access to the
+ device structure improperly.
+ For this reason the lock must also not be per-device.
*/
- if (!down_read_trylock(&sn9c102_disconnect))
+ if (!down_read_trylock(&sn9c102_dev_lock))
return -ERESTARTSYS;
cam = video_get_drvdata(video_devdata(filp));
- if (mutex_lock_interruptible(&cam->dev_mutex)) {
- up_read(&sn9c102_disconnect);
+ if (wait_for_completion_interruptible(&cam->probe)) {
+ up_read(&sn9c102_dev_lock);
+ return -ERESTARTSYS;
+ }
+
+ kref_get(&cam->kref);
+
+ /*
+ Make sure to isolate all the simultaneous opens.
+ */
+ if (mutex_lock_interruptible(&cam->open_mutex)) {
+ kref_put(&cam->kref, sn9c102_release_resources);
+ up_read(&sn9c102_dev_lock);
return -ERESTARTSYS;
}
+ if (cam->state & DEV_DISCONNECTED) {
+ DBG(1, "Device not present");
+ err = -ENODEV;
+ goto out;
+ }
+
if (cam->users) {
- DBG(2, "Device /dev/video%d is busy...", cam->v4ldev->minor);
+ DBG(2, "Device /dev/video%d is already in use",
+ cam->v4ldev->minor);
DBG(3, "Simultaneous opens are not supported");
+ /*
+ open() must follow the open flags and should block
+ eventually while the device is in use.
+ */
if ((filp->f_flags & O_NONBLOCK) ||
(filp->f_flags & O_NDELAY)) {
err = -EWOULDBLOCK;
goto out;
}
- mutex_unlock(&cam->dev_mutex);
- err = wait_event_interruptible_exclusive(cam->open,
- cam->state & DEV_DISCONNECTED
+ DBG(2, "A blocking open() has been requested. Wait for the "
+ "device to be released...");
+ up_read(&sn9c102_dev_lock);
+ /*
+ We will not release the "open_mutex" lock, so that only one
+ process can be in the wait queue below. This way the process
+ will be sleeping while holding the lock, without loosing its
+ priority after any wake_up().
+ */
+ err = wait_event_interruptible_exclusive(cam->wait_open,
+ (cam->state & DEV_DISCONNECTED)
|| !cam->users);
- if (err) {
- up_read(&sn9c102_disconnect);
- return err;
- }
+ down_read(&sn9c102_dev_lock);
+ if (err)
+ goto out;
if (cam->state & DEV_DISCONNECTED) {
- up_read(&sn9c102_disconnect);
- return -ENODEV;
+ err = -ENODEV;
+ goto out;
}
- mutex_lock(&cam->dev_mutex);
}
-
if (cam->state & DEV_MISCONFIGURED) {
err = sn9c102_init(cam);
if (err) {
@@ -1789,36 +1835,33 @@ static int sn9c102_open(struct inode* inode, struct file* filp)
DBG(3, "Video device /dev/video%d is open", cam->v4ldev->minor);
out:
- mutex_unlock(&cam->dev_mutex);
- up_read(&sn9c102_disconnect);
+ mutex_unlock(&cam->open_mutex);
+ if (err)
+ kref_put(&cam->kref, sn9c102_release_resources);
+
+ up_read(&sn9c102_dev_lock);
return err;
}
static int sn9c102_release(struct inode* inode, struct file* filp)
{
- struct sn9c102_device* cam = video_get_drvdata(video_devdata(filp));
+ struct sn9c102_device* cam;
- mutex_lock(&cam->dev_mutex); /* prevent disconnect() to be called */
+ down_write(&sn9c102_dev_lock);
- sn9c102_stop_transfer(cam);
+ cam = video_get_drvdata(video_devdata(filp));
+ sn9c102_stop_transfer(cam);
sn9c102_release_buffers(cam);
-
- if (cam->state & DEV_DISCONNECTED) {
- sn9c102_release_resources(cam);
- usb_put_dev(cam->usbdev);
- mutex_unlock(&cam->dev_mutex);
- kfree(cam);
- return 0;
- }
-
cam->users--;
- wake_up_interruptible_nr(&cam->open, 1);
+ wake_up_interruptible_nr(&cam->wait_open, 1);
DBG(3, "Video device /dev/video%d closed", cam->v4ldev->minor);
- mutex_unlock(&cam->dev_mutex);
+ kref_put(&cam->kref, sn9c102_release_resources);
+
+ up_write(&sn9c102_dev_lock);
return 0;
}
@@ -2085,7 +2128,6 @@ static int sn9c102_mmap(struct file* filp, struct vm_area_struct *vma)
vma->vm_ops = &sn9c102_vm_ops;
vma->vm_private_data = &cam->frame[i];
-
sn9c102_vm_open(vma);
mutex_unlock(&cam->fileop_mutex);
@@ -3215,8 +3257,6 @@ sn9c102_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
goto fail;
}
- mutex_init(&cam->dev_mutex);
-
r = sn9c102_read_reg(cam, 0x00);
if (r < 0 || (r != 0x10 && r != 0x11 && r != 0x12)) {
DBG(1, "Sorry, this is not a SN9C1xx-based camera "
@@ -3282,7 +3322,7 @@ sn9c102_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
cam->v4ldev->release = video_device_release;
video_set_drvdata(cam->v4ldev, cam);
- mutex_lock(&cam->dev_mutex);
+ init_completion(&cam->probe);
err = video_register_device(cam->v4ldev, VFL_TYPE_GRABBER,
video_nr[dev_nr]);
@@ -3292,7 +3332,7 @@ sn9c102_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
DBG(1, "Free /dev/videoX node not found");
video_nr[dev_nr] = -1;
dev_nr = (dev_nr < SN9C102_MAX_DEVICES-1) ? dev_nr+1 : 0;
- mutex_unlock(&cam->dev_mutex);
+ complete_all(&cam->probe);
goto fail;
}
@@ -3318,8 +3358,10 @@ sn9c102_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
#endif
usb_set_intfdata(intf, cam);
+ kref_init(&cam->kref);
+ usb_get_dev(cam->usbdev);
- mutex_unlock(&cam->dev_mutex);
+ complete_all(&cam->probe);
return 0;
@@ -3336,40 +3378,31 @@ fail:
static void sn9c102_usb_disconnect(struct usb_interface* intf)
{
- struct sn9c102_device* cam = usb_get_intfdata(intf);
-
- if (!cam)
- return;
+ struct sn9c102_device* cam;
- down_write(&sn9c102_disconnect);
+ down_write(&sn9c102_dev_lock);
- mutex_lock(&cam->dev_mutex);
+ cam = usb_get_intfdata(intf);
DBG(2, "Disconnecting %s...", cam->v4ldev->name);
- wake_up_interruptible_all(&cam->open);
-
if (cam->users) {
DBG(2, "Device /dev/video%d is open! Deregistration and "
- "memory deallocation are deferred on close.",
+ "memory deallocation are deferred.",
cam->v4ldev->minor);
cam->state |= DEV_MISCONFIGURED;
sn9c102_stop_transfer(cam);
cam->state |= DEV_DISCONNECTED;
wake_up_interruptible(&cam->wait_frame);
wake_up(&cam->wait_stream);
- usb_get_dev(cam->usbdev);
- } else {
+ } else
cam->state |= DEV_DISCONNECTED;
- sn9c102_release_resources(cam);
- }
- mutex_unlock(&cam->dev_mutex);
+ wake_up_interruptible_all(&cam->wait_open);
- if (!cam->users)
- kfree(cam);
+ kref_put(&cam->kref, sn9c102_release_resources);
- up_write(&sn9c102_disconnect);
+ up_write(&sn9c102_dev_lock);
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-28 11:15:02 +0300