V4L/DVB (6056): ivtv: move serialization to the fileops level

Serialization is now done on the open/close/ioctl level and also when the
read/write/poll start an encoder/decoder stream.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/ivtv/ivtv-fileops.c

@@ -502,7 +502,9 @@ ssize_t ivtv_v4l2_read(struct file * filp, char __user *buf, size_t count, loff_
 
 	IVTV_DEBUG_HI_FILE("read %zd bytes from %s\n", count, s->name);
 
+	mutex_lock(&itv->serialize_lock);
 	rc = ivtv_start_capture(id);
+	mutex_unlock(&itv->serialize_lock);
 	if (rc)
 		return rc;
 	return ivtv_read_pos(s, buf, count, pos, filp->f_flags & O_NONBLOCK);
@@ -613,7 +615,9 @@ ssize_t ivtv_v4l2_write(struct file *filp, const char __user *user_buf, size_t c
 	}
 
 	/* Start decoder (returns 0 if already started) */
+	mutex_lock(&itv->serialize_lock);
 	rc = ivtv_start_decoding(id, itv->speed);
+	mutex_unlock(&itv->serialize_lock);
 	if (rc) {
 		IVTV_DEBUG_WARN("Failed start decode stream %s\n", s->name);
 
@@ -681,8 +685,11 @@ unsigned int ivtv_v4l2_enc_poll(struct file *filp, poll_table * wait)
 
 	/* Start a capture if there is none */
 	if (!eof && !test_bit(IVTV_F_S_STREAMING, &s->s_flags)) {
-		int rc = ivtv_start_capture(id);
+		int rc;
 
+		mutex_lock(&itv->serialize_lock);
+		rc = ivtv_start_capture(id);
+		mutex_unlock(&itv->serialize_lock);
 		if (rc) {
 			IVTV_DEBUG_INFO("Could not start capture for %s (%d)\n",
 					s->name, rc);
@@ -788,6 +795,7 @@ int ivtv_v4l2_close(struct inode *inode, struct file *filp)
 	/* 'Unclaim' this stream */
 
 	/* Stop radio */
+	mutex_lock(&itv->serialize_lock);
 	if (id->type == IVTV_ENC_STREAM_TYPE_RAD) {
 		/* Closing radio device, return to TV mode */
 		ivtv_mute(itv);
@@ -822,53 +830,26 @@ int ivtv_v4l2_close(struct inode *inode, struct file *filp)
 		ivtv_stop_capture(id, 0);
 	}
 	kfree(id);
+	mutex_unlock(&itv->serialize_lock);
 	return 0;
 }
 
-int ivtv_v4l2_open(struct inode *inode, struct file *filp)
+static int ivtv_serialized_open(struct ivtv_stream *s, struct file *filp)
 {
-	int x, y = 0;
+	struct ivtv *itv = s->itv;
 	struct ivtv_open_id *item;
-	struct ivtv *itv = NULL;
-	struct ivtv_stream *s = NULL;
-	int minor = iminor(inode);
-
-	/* Find which card this open was on */
-	spin_lock(&ivtv_cards_lock);
-	for (x = 0; itv == NULL && x < ivtv_cards_active; x++) {
-		/* find out which stream this open was on */
-		for (y = 0; y < IVTV_MAX_STREAMS; y++) {
-			s = &ivtv_cards[x]->streams[y];
-			if (s->v4l2dev && s->v4l2dev->minor == minor) {
-				itv = ivtv_cards[x];
-				break;
-			}
-		}
-	}
-	spin_unlock(&ivtv_cards_lock);
 
-	if (itv == NULL) {
-		/* Couldn't find a device registered
-		   on that minor, shouldn't happen! */
-		IVTV_WARN("No ivtv device found on minor %d\n", minor);
-		return -ENXIO;
-	}
-
-	if (ivtv_init_on_first_open(itv)) {
-		IVTV_ERR("Failed to initialize on minor %d\n", minor);
-		return -ENXIO;
-	}
 	IVTV_DEBUG_FILE("open %s\n", s->name);
 
-	if (y == IVTV_DEC_STREAM_TYPE_MPG &&
+	if (s->type == IVTV_DEC_STREAM_TYPE_MPG &&
 		test_bit(IVTV_F_S_CLAIMED, &itv->streams[IVTV_DEC_STREAM_TYPE_YUV].s_flags))
 		return -EBUSY;
 
-	if (y == IVTV_DEC_STREAM_TYPE_YUV &&
+	if (s->type == IVTV_DEC_STREAM_TYPE_YUV &&
 		test_bit(IVTV_F_S_CLAIMED, &itv->streams[IVTV_DEC_STREAM_TYPE_MPG].s_flags))
 		return -EBUSY;
 
-	if (y == IVTV_DEC_STREAM_TYPE_YUV) {
+	if (s->type == IVTV_DEC_STREAM_TYPE_YUV) {
 		if (read_reg(0x82c) == 0) {
 			IVTV_ERR("Tried to open YUV output device but need to send data to mpeg decoder before it can be used\n");
 			/* return -ENODEV; */
@@ -883,7 +864,7 @@ int ivtv_v4l2_open(struct inode *inode, struct file *filp)
 		return -ENOMEM;
 	}
 	item->itv = itv;
-	item->type = y;
+	item->type = s->type;
 	v4l2_prio_open(&itv->prio, &item->prio);
 
 	item->open_id = itv->open_id++;
@@ -925,14 +906,50 @@ int ivtv_v4l2_open(struct inode *inode, struct file *filp)
 	}
 
 	/* YUV or MPG Decoding Mode? */
-	if (y == IVTV_DEC_STREAM_TYPE_MPG)
+	if (s->type == IVTV_DEC_STREAM_TYPE_MPG)
 		clear_bit(IVTV_F_I_DEC_YUV, &itv->i_flags);
-	else if (y == IVTV_DEC_STREAM_TYPE_YUV)
-	{
+	else if (s->type == IVTV_DEC_STREAM_TYPE_YUV)
 		set_bit(IVTV_F_I_DEC_YUV, &itv->i_flags);
+	return 0;
+}
+
+int ivtv_v4l2_open(struct inode *inode, struct file *filp)
+{
+	int res, x, y = 0;
+	struct ivtv *itv = NULL;
+	struct ivtv_stream *s = NULL;
+	int minor = iminor(inode);
+
+	/* Find which card this open was on */
+	spin_lock(&ivtv_cards_lock);
+	for (x = 0; itv == NULL && x < ivtv_cards_active; x++) {
+		/* find out which stream this open was on */
+		for (y = 0; y < IVTV_MAX_STREAMS; y++) {
+			s = &ivtv_cards[x]->streams[y];
+			if (s->v4l2dev && s->v4l2dev->minor == minor) {
+				itv = ivtv_cards[x];
+				break;
+			}
+		}
 	}
+	spin_unlock(&ivtv_cards_lock);
 
-	return 0;
+	if (itv == NULL) {
+		/* Couldn't find a device registered
+		   on that minor, shouldn't happen! */
+		IVTV_WARN("No ivtv device found on minor %d\n", minor);
+		return -ENXIO;
+	}
+
+	mutex_lock(&itv->serialize_lock);
+	if (ivtv_init_on_first_open(itv)) {
+		IVTV_ERR("Failed to initialize on minor %d\n", minor);
+		mutex_unlock(&itv->serialize_lock);
+		return -ENXIO;
+	}
+	res = ivtv_serialized_open(s, filp);
+	mutex_unlock(&itv->serialize_lock);
+	return res;
 }
 
 void ivtv_mute(struct ivtv *itv)

drivers/media/video/ivtv/ivtv-ioctl.c

@@ -1446,11 +1446,15 @@ static int ivtv_decoder_ioctls(struct file *filp, unsigned int cmd, void *arg)
 				return 0;
 			if (nonblocking)
 				return -EAGAIN;
-			/* wait for event */
+			/* Wait for event. Note that serialize_lock is locked,
+			   so to allow other processes to access the driver while
+			   we are waiting unlock first and later lock again. */
+			mutex_unlock(&itv->serialize_lock);
 			prepare_to_wait(&itv->event_waitq, &wait, TASK_INTERRUPTIBLE);
 			if ((itv->i_flags & (IVTV_F_I_EV_DEC_STOPPED|IVTV_F_I_EV_VSYNC)) == 0)
 				schedule();
 			finish_wait(&itv->event_waitq, &wait);
+			mutex_lock(&itv->serialize_lock);
 			if (signal_pending(current)) {
 				/* return if a signal was received */
 				IVTV_DEBUG_INFO("User stopped wait for event\n");
@@ -1580,12 +1584,9 @@ static int ivtv_v4l2_do_ioctl(struct inode *inode, struct file *filp,
 	return 0;
 }
 
-int ivtv_v4l2_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
-		    unsigned long arg)
+static int ivtv_serialized_ioctl(struct ivtv *itv, struct inode *inode, struct file *filp,
+		unsigned int cmd, unsigned long arg)
 {
-	struct ivtv_open_id *id = (struct ivtv_open_id *)filp->private_data;
-	struct ivtv *itv = id->itv;
-
 	/* Filter dvb ioctls that cannot be handled by video_usercopy */
 	switch (cmd) {
 	case VIDEO_SELECT_SOURCE:
@@ -1620,3 +1621,16 @@ int ivtv_v4l2_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
 	}
 	return video_usercopy(inode, filp, cmd, arg, ivtv_v4l2_do_ioctl);
 }
+
+int ivtv_v4l2_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
+		    unsigned long arg)
+{
+	struct ivtv_open_id *id = (struct ivtv_open_id *)filp->private_data;
+	struct ivtv *itv = id->itv;
+	int res;
+
+	mutex_lock(&itv->serialize_lock);
+	res = ivtv_serialized_ioctl(itv, inode, filp, cmd, arg);
+	mutex_unlock(&itv->serialize_lock);
+	return res;
+}

drivers/media/video/ivtv/ivtv-streams.c

@@ -437,9 +437,6 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
 	if (s->v4l2dev == NULL)
 		return -EINVAL;
 
-	/* Big serialization lock to ensure no two streams are started
-	   simultaneously: that can give all sorts of weird results. */
-	mutex_lock(&itv->serialize_lock);
 	IVTV_DEBUG_INFO("Start encoder stream %s\n", s->name);
 
 	switch (s->type) {
@@ -481,7 +478,6 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
 			0, sizeof(itv->vbi.sliced_mpeg_size));
 		break;
 	default:
-		mutex_unlock(&itv->serialize_lock);
 		return -EINVAL;
 	}
 	s->subtype = subtype;
@@ -564,7 +560,6 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
 	if (ivtv_vapi(itv, CX2341X_ENC_START_CAPTURE, 2, captype, subtype))
 	{
 		IVTV_DEBUG_WARN( "Error starting capture!\n");
-		mutex_unlock(&itv->serialize_lock);
 		return -EINVAL;
 	}
 
@@ -580,7 +575,6 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
 
 	/* you're live! sit back and await interrupts :) */
 	atomic_inc(&itv->capturing);
-	mutex_unlock(&itv->serialize_lock);
 	return 0;
 }
 
@@ -751,9 +745,6 @@ int ivtv_stop_v4l2_encode_stream(struct ivtv_stream *s, int gop_end)
 		stopmode = 1;
 	}
 
-	/* ensure these actions are done only once */
-	mutex_lock(&itv->serialize_lock);
-
 	/* end_capture */
 	/* when: 0 =  end of GOP  1 = NOW!, type: 0 = mpeg, subtype: 3 = video+audio */
 	ivtv_vapi(itv, CX2341X_ENC_STOP_CAPTURE, 3, stopmode, cap_type, s->subtype);
@@ -810,7 +801,6 @@ int ivtv_stop_v4l2_encode_stream(struct ivtv_stream *s, int gop_end)
 		ivtv_set_irq_mask(itv, IVTV_IRQ_ENC_VBI_CAP);
 
 	if (atomic_read(&itv->capturing) > 0) {
-		mutex_unlock(&itv->serialize_lock);
 		return 0;
 	}
 
@@ -827,7 +817,6 @@ int ivtv_stop_v4l2_encode_stream(struct ivtv_stream *s, int gop_end)
 	}
 
 	wake_up(&s->waitq);
-	mutex_unlock(&itv->serialize_lock);
 
 	return 0;
 }