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>

3 files changed, 76 insertions, 56 deletions

diff --git a/drivers/media/video/ivtv/ivtv-fileops.c b/drivers/media/video/ivtv/ivtv-fileops.c
index 846e9bfa41f0..1f3c8d0310f5 100644
--- a/drivers/media/video/ivtv/ivtv-fileops.c
+++ b/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 @@ retry:
         }
 
         /* 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)
diff --git a/drivers/media/video/ivtv/ivtv-ioctl.c b/drivers/media/video/ivtv/ivtv-ioctl.c
index 2c0f27241332..2061d82653fc 100644
--- a/drivers/media/video/ivtv/ivtv-ioctl.c
+++ b/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;
+}
diff --git a/drivers/media/video/ivtv/ivtv-streams.c b/drivers/media/video/ivtv/ivtv-streams.c
index fab5c51b1519..65fa247e33c5 100644
--- a/drivers/media/video/ivtv/ivtv-streams.c
+++ b/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;
 }