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authorMauro Carvalho Chehab <mchehab@infradead.org>2007-11-11 01:08:26 -0300
committerMauro Carvalho Chehab <mchehab@infradead.org>2008-01-25 19:02:06 -0200
commita225452ef80a7bd894fd2dfd01a4973d444152f4 (patch)
tree397c483c75751106545ef989d83fe25a7c57347b /drivers/media/video/em28xx
parenta3a048cea301baba5d451991074a85dc20a8f228 (diff)
V4L/DVB (6583): Fix em28xx read stream locking
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>
Diffstat (limited to 'drivers/media/video/em28xx')
-rw-r--r--drivers/media/video/em28xx/em28xx-video.c77
-rw-r--r--drivers/media/video/em28xx/em28xx.h5
2 files changed, 59 insertions, 23 deletions
diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index 5b17ca9cad1..f0191779a8e 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -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);
diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index f8ad0f4ae6d..3efc05d2df6 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -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 */