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V4L/DVB (6583): Fix em28xx read stream locking

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On some situations, closing an streaming application and re-opening were
returning -EBUSY.

Uses the same locking schema also present on cx88.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Mauro Carvalho Chehab 2007-11-11 01:08:26 -03:00
parent a3a048cea3
commit a225452ef8
2 changed files with 59 additions and 23 deletions
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77
drivers/media/video/em28xx/em28xx-video.c
View File

@ -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()
* 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);
if (res_check(fh))
res_free(fh);
mutex_lock(&dev->lock);
if (fh->reader == 1)
fh->reader = 0;
if (dev->users == 1) {
dev->reader = 0;
em28xx_uninit_isoc(dev);
em28xx_release_buffers(dev);
dev->io = IO_NONE;
/* the device is already disconnect,
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 *dev = fh->dev;
if (unlikely(res_get(fh) < 0))
return -EBUSY;
mutex_lock(&dev->lock);
if (dev->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
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) {
em28xx_videodbg("V4L2_BUF_TYPE_VBI_CAPTURE is set\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");
mutex_unlock(&dev->lock);
return -EINVAL;
} else {
dev->reader = 1;
fh->reader = 1;
}
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 *dev = fh->dev;
if (unlikely(res_get(fh) < 0))
return POLLERR;
mutex_lock(&dev->lock);
if (dev->state & DEV_DISCONNECTED) {
@ -572,15 +610,10 @@ static int em28xx_v4l2_mmap(struct file *filp, struct vm_area_struct *vma)
void *pos;
u32 i;
mutex_lock(&dev->lock);
if (dev->reader > 0 && fh->reader == 0) {
mutex_unlock(&dev->lock);
if (unlikely(res_get(fh) < 0))
return -EBUSY;
} else {
dev->reader = 1;
fh->reader = 1;
}
mutex_lock(&dev->lock);
if (dev->state & DEV_DISCONNECTED) {
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))
return -EINVAL;
if (unlikely(res_get(fh) < 0))
return -EBUSY;
dev->stream = STREAM_ON; /* FIXME: Start video capture here? */
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);
mutex_unlock(&dev->lock);

5
drivers/media/video/em28xx/em28xx.h
View File

@ -224,6 +224,8 @@ struct em28xx {
unsigned int has_msp34xx:1;
unsigned int has_tda9887:1;
unsigned int stream_on:1; /* Locks streams */
u32 i2s_speed; /* I2S speed for audio digital stream */
enum em28xx_decoder decoder;
@ -258,7 +260,6 @@ struct em28xx {
int vscale; /* vertical scale factor (see datasheet) */
int interlaced; /* 1=interlace fileds, 0=just top fileds */
int type;
unsigned int reader:1;
unsigned long hash; /* eeprom 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 *dev;
unsigned int reader:1;
unsigned int stream_on:1; /* Locks streams */
};
/* Provided by em28xx-i2c.c */