V4L/DVB (6583): Fix em28xx read stream locking (a225452e) · Commits · e / devices / android_kernel_fairphone_FP4

drivers/media/video/em28xx/em28xx-video.c

+56 −21

Original line number	Original line	Diff line number	Diff line
	@@ -225,6 +225,44 @@ static void video_mux(struct em28xx *dev, int index)
	}		}
	}		}

			/* Usage lock check functions */
			static int res_get(struct em28xx_fh *fh)
			{
			struct em28xx *dev = fh->dev;
			int rc = 0;

			/* This instance already has stream_on */
			if (fh->stream_on)
			return rc;

			mutex_lock(&dev->lock);

			if (dev->stream_on)
			rc = -EINVAL;
			else {
			dev->stream_on = 1;
			fh->stream_on = 1;
			}

			mutex_unlock(&dev->lock);
			return rc;
			}

			static int res_check(struct em28xx_fh *fh)
			{
			return (fh->stream_on);
			}

			static void res_free(struct em28xx_fh *fh)
			{
			struct em28xx *dev = fh->dev;

			mutex_lock(&dev->lock);
			fh->stream_on = 0;
			dev->stream_on = 0;
			mutex_unlock(&dev->lock);
			}

	/*		/*
	* em28xx_v4l2_open()		* em28xx_v4l2_open()
	* inits the device and starts isoc transfer		* inits the device and starts isoc transfer
	@@ -328,15 +366,16 @@ static int em28xx_v4l2_close(struct inode inode, struct file filp)

	em28xx_videodbg("users=%d\n", dev->users);		em28xx_videodbg("users=%d\n", dev->users);


			if (res_check(fh))
			res_free(fh);

	mutex_lock(&dev->lock);		mutex_lock(&dev->lock);
	if (fh->reader == 1)
	fh->reader = 0;

	if (dev->users == 1) {		if (dev->users == 1) {
	dev->reader = 0;

	em28xx_uninit_isoc(dev);		em28xx_uninit_isoc(dev);
	em28xx_release_buffers(dev);		em28xx_release_buffers(dev);
			dev->io = IO_NONE;

	/* the device is already disconnect,		/* the device is already disconnect,
	free the remaining resources */		free the remaining resources */
	@@ -377,16 +416,15 @@ em28xx_v4l2_read(struct file filp, char __user buf, size_t count,
	struct em28xx_fh *fh = filp->private_data;		struct em28xx_fh *fh = filp->private_data;
	struct em28xx *dev = fh->dev;		struct em28xx *dev = fh->dev;


			if (unlikely(res_get(fh) < 0))
			return -EBUSY;

	mutex_lock(&dev->lock);		mutex_lock(&dev->lock);

	if (dev->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)		if (dev->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
	em28xx_videodbg("V4l2_Buf_type_videocapture is set\n");		em28xx_videodbg("V4l2_Buf_type_videocapture is set\n");

	if (dev->reader > 0 && fh->reader == 0) {
	mutex_unlock(&dev->lock);
	return -EBUSY;
	}

	if (dev->type == V4L2_BUF_TYPE_VBI_CAPTURE) {		if (dev->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
	em28xx_videodbg("V4L2_BUF_TYPE_VBI_CAPTURE is set\n");		em28xx_videodbg("V4L2_BUF_TYPE_VBI_CAPTURE is set\n");
	em28xx_videodbg("not supported yet! ...\n");		em28xx_videodbg("not supported yet! ...\n");
	@@ -425,9 +463,6 @@ em28xx_v4l2_read(struct file filp, char __user buf, size_t count,
	" the device again to choose the read method\n");		" the device again to choose the read method\n");
	mutex_unlock(&dev->lock);		mutex_unlock(&dev->lock);
	return -EINVAL;		return -EINVAL;
	} else {
	dev->reader = 1;
	fh->reader = 1;
	}		}

	if (dev->io == IO_NONE) {		if (dev->io == IO_NONE) {
	@@ -499,6 +534,9 @@ static unsigned int em28xx_v4l2_poll(struct file filp, poll_table wait)
	struct em28xx_fh *fh = filp->private_data;		struct em28xx_fh *fh = filp->private_data;
	struct em28xx *dev = fh->dev;		struct em28xx *dev = fh->dev;

			if (unlikely(res_get(fh) < 0))
			return POLLERR;

	mutex_lock(&dev->lock);		mutex_lock(&dev->lock);

	if (dev->state & DEV_DISCONNECTED) {		if (dev->state & DEV_DISCONNECTED) {
	@@ -572,15 +610,10 @@ static int em28xx_v4l2_mmap(struct file filp, struct vm_area_struct vma)
	void *pos;		void *pos;
	u32 i;		u32 i;

	mutex_lock(&dev->lock);		if (unlikely(res_get(fh) < 0))

	if (dev->reader > 0 && fh->reader == 0) {
	mutex_unlock(&dev->lock);
	return -EBUSY;		return -EBUSY;
	} else {
	dev->reader = 1;		mutex_lock(&dev->lock);
	fh->reader = 1;
	}

	if (dev->state & DEV_DISCONNECTED) {		if (dev->state & DEV_DISCONNECTED) {
	em28xx_videodbg("mmap: device not present\n");		em28xx_videodbg("mmap: device not present\n");
	@@ -1219,6 +1252,9 @@ static int em28xx_do_ioctl(struct inode inode, struct file filp,
	if (list_empty(&dev->inqueue))		if (list_empty(&dev->inqueue))
	return -EINVAL;		return -EINVAL;

			if (unlikely(res_get(fh) < 0))
			return -EBUSY;

	dev->stream = STREAM_ON; /* FIXME: Start video capture here? */		dev->stream = STREAM_ON; /* FIXME: Start video capture here? */

	em28xx_videodbg("VIDIOC_STREAMON: starting stream\n");		em28xx_videodbg("VIDIOC_STREAMON: starting stream\n");
	@@ -1243,7 +1279,6 @@ static int em28xx_do_ioctl(struct inode inode, struct file filp,
	}		}
	}		}

	fh->reader = 0;
	em28xx_empty_framequeues(dev);		em28xx_empty_framequeues(dev);
	mutex_unlock(&dev->lock);		mutex_unlock(&dev->lock);

drivers/media/video/em28xx/em28xx.h

+3 −2

Original line number	Original line	Diff line number	Diff line
	@@ -224,6 +224,8 @@ struct em28xx {
	unsigned int has_msp34xx:1;		unsigned int has_msp34xx:1;
	unsigned int has_tda9887:1;		unsigned int has_tda9887:1;

			unsigned int stream_on:1; /* Locks streams */

	u32 i2s_speed; /* I2S speed for audio digital stream */		u32 i2s_speed; /* I2S speed for audio digital stream */

	enum em28xx_decoder decoder;		enum em28xx_decoder decoder;
	@@ -258,7 +260,6 @@ struct em28xx {
	int vscale; /* vertical scale factor (see datasheet) */		int vscale; /* vertical scale factor (see datasheet) */
	int interlaced; /* 1=interlace fileds, 0=just top fileds */		int interlaced; /* 1=interlace fileds, 0=just top fileds */
	int type;		int type;
	unsigned int reader:1;

	unsigned long hash; /* eeprom hash - for boards with generic ID */		unsigned long hash; /* eeprom hash - for boards with generic ID */
	unsigned long i2c_hash; /* i2c devicelist hash - for boards with generic ID */		unsigned long i2c_hash; /* i2c devicelist hash - for boards with generic ID */
	@@ -297,7 +298,7 @@ struct em28xx {

	struct em28xx_fh {		struct em28xx_fh {
	struct em28xx *dev;		struct em28xx *dev;
	unsigned int reader:1;		unsigned int stream_on:1; /* Locks streams */
	};		};

	/* Provided by em28xx-i2c.c */		/* Provided by em28xx-i2c.c */