From 3770be34199ace8c497ce454cebd7d63347dc4c3 Mon Sep 17 00:00:00 2001 From: Luca Risolia Date: Wed, 13 Jun 2007 14:37:50 -0300 Subject: V4L/DVB (5765): SN9C1xx driver updates - Add support for pair OV7630+SN9C120 - Better and safe locking mechanism of the device structure on open(), close() and disconnect() - Use kref for handling device deallocation - Generic cleanups Signed-off-by: Luca Risolia Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/sn9c102/sn9c102_core.c | 173 +++++++++++++++++------------ 1 file changed, 103 insertions(+), 70 deletions(-) (limited to 'drivers/media/video/sn9c102/sn9c102_core.c') 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 "" #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 Debugging information level, from 0 to 3:" + " " + "\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); } -- cgit v1.2.1