V4L/DVB (6601): V4L: videobuf-core locking fixes and comments
- Add comments to functions that require that caller hold q->lock - Add __videobuf_mmap_free that doesn't hold q->lock for use within videobuf - Add locking to videobuf_mmap_free - Fix linux/drivers/media/common/saa7146_video.c which was holding lock around videobuf_read_stop - Add locking to functions that operate on a queue - Add videobuf_stop to take care of stopping in both the read and stream case TODO: bttv still has an unsafe call to videobuf_queue_is_busy Signed-off-by: Brandon Philips <bphilips@suse.de> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
Brandon Philips
Mauro Carvalho Chehab
parent
63337dd3f5
commit
19bc5133da
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@ -1440,10 +1440,7 @@ static void video_close(struct saa7146_dev *dev, struct file *file)
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err = saa7146_stop_preview(fh);
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}
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// release all capture buffers
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mutex_lock(&q->lock);
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videobuf_read_stop(q);
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mutex_unlock(&q->lock);
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videobuf_stop(q);
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/* hmm, why is this function declared void? */
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/* return err */
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@ -141,6 +141,7 @@ void videobuf_queue_core_init(struct videobuf_queue* q,
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INIT_LIST_HEAD(&q->stream);
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}
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/* Locking: Only usage in bttv unsafe find way to remove */
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int videobuf_queue_is_busy(struct videobuf_queue *q)
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{
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int i;
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@ -178,6 +179,7 @@ int videobuf_queue_is_busy(struct videobuf_queue *q)
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return 0;
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}
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/* Locking: Caller holds q->lock */
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void videobuf_queue_cancel(struct videobuf_queue *q)
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{
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unsigned long flags=0;
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@ -208,6 +210,7 @@ void videobuf_queue_cancel(struct videobuf_queue *q)
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/* --------------------------------------------------------------------- */
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/* Locking: Caller holds q->lock */
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enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
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{
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enum v4l2_field field = q->field;
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@ -226,6 +229,7 @@ enum v4l2_field videobuf_next_field(struct videobuf_queue *q)
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return field;
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}
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/* Locking: Caller holds q->lock */
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static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
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struct videobuf_buffer *vb, enum v4l2_buf_type type)
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{
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@ -281,20 +285,108 @@ static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b,
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b->sequence = vb->field_count >> 1;
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}
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/* Locking: Caller holds q->lock */
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static int __videobuf_mmap_free(struct videobuf_queue *q)
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{
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int i;
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int rc;
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if (!q)
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return 0;
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MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
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rc = CALL(q,mmap_free,q);
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if (rc<0)
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return rc;
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for (i = 0; i < VIDEO_MAX_FRAME; i++) {
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if (NULL == q->bufs[i])
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continue;
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q->ops->buf_release(q,q->bufs[i]);
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kfree(q->bufs[i]);
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q->bufs[i] = NULL;
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}
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return rc;
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}
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int videobuf_mmap_free(struct videobuf_queue *q)
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{
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int ret;
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mutex_lock(&q->lock);
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ret = __videobuf_mmap_free(q);
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mutex_unlock(&q->lock);
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return ret;
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}
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/* Locking: Caller holds q->lock */
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static int __videobuf_mmap_setup(struct videobuf_queue *q,
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unsigned int bcount, unsigned int bsize,
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enum v4l2_memory memory)
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{
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unsigned int i;
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int err;
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MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
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err = __videobuf_mmap_free(q);
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if (0 != err)
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return err;
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/* Allocate and initialize buffers */
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for (i = 0; i < bcount; i++) {
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q->bufs[i] = videobuf_alloc(q);
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if (q->bufs[i] == NULL)
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break;
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q->bufs[i]->i = i;
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q->bufs[i]->input = UNSET;
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q->bufs[i]->memory = memory;
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q->bufs[i]->bsize = bsize;
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switch (memory) {
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case V4L2_MEMORY_MMAP:
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q->bufs[i]->boff = bsize * i;
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break;
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case V4L2_MEMORY_USERPTR:
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case V4L2_MEMORY_OVERLAY:
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/* nothing */
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break;
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}
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}
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if (!i)
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return -ENOMEM;
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dprintk(1,"mmap setup: %d buffers, %d bytes each\n",
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i, bsize);
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return i;
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}
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int videobuf_mmap_setup(struct videobuf_queue *q,
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unsigned int bcount, unsigned int bsize,
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enum v4l2_memory memory)
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{
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int ret;
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mutex_lock(&q->lock);
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ret = __videobuf_mmap_setup(q, bcount, bsize, memory);
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mutex_unlock(&q->lock);
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return ret;
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}
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int videobuf_reqbufs(struct videobuf_queue *q,
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struct v4l2_requestbuffers *req)
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{
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unsigned int size,count;
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int retval;
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if (req->type != q->type) {
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dprintk(1,"reqbufs: queue type invalid\n");
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return -EINVAL;
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}
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if (req->count < 1) {
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dprintk(1,"reqbufs: count invalid (%d)\n",req->count);
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return -EINVAL;
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}
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if (req->memory != V4L2_MEMORY_MMAP &&
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req->memory != V4L2_MEMORY_USERPTR &&
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req->memory != V4L2_MEMORY_OVERLAY) {
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@ -303,6 +395,12 @@ int videobuf_reqbufs(struct videobuf_queue *q,
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}
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mutex_lock(&q->lock);
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if (req->type != q->type) {
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dprintk(1,"reqbufs: queue type invalid\n");
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retval = -EINVAL;
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goto done;
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}
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if (q->streaming) {
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dprintk(1,"reqbufs: streaming already exists\n");
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retval = -EBUSY;
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@ -323,7 +421,7 @@ int videobuf_reqbufs(struct videobuf_queue *q,
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dprintk(1,"reqbufs: bufs=%d, size=0x%x [%d pages total]\n",
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count, size, (count*size)>>PAGE_SHIFT);
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retval = videobuf_mmap_setup(q,count,size,req->memory);
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retval = __videobuf_mmap_setup(q,count,size,req->memory);
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if (retval < 0) {
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dprintk(1,"reqbufs: mmap setup returned %d\n",retval);
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goto done;
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@ -338,20 +436,28 @@ int videobuf_reqbufs(struct videobuf_queue *q,
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int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b)
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{
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int ret = -EINVAL;
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mutex_lock(&q->lock);
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if (unlikely(b->type != q->type)) {
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dprintk(1,"querybuf: Wrong type.\n");
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return -EINVAL;
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goto done;
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}
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if (unlikely(b->index < 0 || b->index >= VIDEO_MAX_FRAME)) {
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dprintk(1,"querybuf: index out of range.\n");
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return -EINVAL;
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goto done;
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}
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if (unlikely(NULL == q->bufs[b->index])) {
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dprintk(1,"querybuf: buffer is null.\n");
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return -EINVAL;
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goto done;
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}
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videobuf_status(q,b,q->bufs[b->index],q->type);
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return 0;
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ret = 0;
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done:
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mutex_unlock(&q->lock);
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return ret;
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}
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int videobuf_qbuf(struct videobuf_queue *q,
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@ -541,22 +647,30 @@ int videobuf_streamon(struct videobuf_queue *q)
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return retval;
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}
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int videobuf_streamoff(struct videobuf_queue *q)
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/* Locking: Caller holds q->lock */
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static int __videobuf_streamoff(struct videobuf_queue *q)
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{
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int retval = -EINVAL;
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mutex_lock(&q->lock);
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if (!q->streaming)
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goto done;
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return -EINVAL;
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videobuf_queue_cancel(q);
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q->streaming = 0;
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retval = 0;
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done:
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return 0;
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}
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int videobuf_streamoff(struct videobuf_queue *q)
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{
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int retval;
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mutex_lock(&q->lock);
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retval = __videobuf_streamoff(q);
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mutex_unlock(&q->lock);
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return retval;
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}
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/* Locking: Caller holds q->lock */
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static ssize_t videobuf_read_zerocopy(struct videobuf_queue *q,
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char __user *data,
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size_t count, loff_t *ppos)
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@ -691,6 +805,7 @@ ssize_t videobuf_read_one(struct videobuf_queue *q,
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return retval;
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}
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/* Locking: Caller holds q->lock */
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int videobuf_read_start(struct videobuf_queue *q)
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{
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enum v4l2_field field;
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@ -705,7 +820,7 @@ int videobuf_read_start(struct videobuf_queue *q)
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count = VIDEO_MAX_FRAME;
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size = PAGE_ALIGN(size);
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err = videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
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err = __videobuf_mmap_setup(q, count, size, V4L2_MEMORY_USERPTR);
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if (err < 0)
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return err;
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@ -728,12 +843,13 @@ int videobuf_read_start(struct videobuf_queue *q)
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return 0;
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}
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void videobuf_read_stop(struct videobuf_queue *q)
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static void __videobuf_read_stop(struct videobuf_queue *q)
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{
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int i;
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videobuf_queue_cancel(q);
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videobuf_mmap_free(q);
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__videobuf_mmap_free(q);
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INIT_LIST_HEAD(&q->stream);
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for (i = 0; i < VIDEO_MAX_FRAME; i++) {
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if (NULL == q->bufs[i])
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@ -743,8 +859,30 @@ void videobuf_read_stop(struct videobuf_queue *q)
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}
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q->read_buf = NULL;
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q->reading = 0;
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}
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void videobuf_read_stop(struct videobuf_queue *q)
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{
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mutex_lock(&q->lock);
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__videobuf_read_stop(q);
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mutex_unlock(&q->lock);
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}
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void videobuf_stop(struct videobuf_queue *q)
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{
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mutex_lock(&q->lock);
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if (q->streaming)
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__videobuf_streamoff(q);
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if (q->reading)
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__videobuf_read_stop(q);
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mutex_unlock(&q->lock);
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}
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ssize_t videobuf_read_stream(struct videobuf_queue *q,
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char __user *data, size_t count, loff_t *ppos,
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int vbihack, int nonblocking)
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@ -858,75 +996,6 @@ unsigned int videobuf_poll_stream(struct file *file,
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return rc;
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}
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int videobuf_mmap_setup(struct videobuf_queue *q,
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unsigned int bcount, unsigned int bsize,
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enum v4l2_memory memory)
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{
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unsigned int i;
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int err;
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MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
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err = videobuf_mmap_free(q);
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if (0 != err)
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return err;
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/* Allocate and initialize buffers */
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for (i = 0; i < bcount; i++) {
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q->bufs[i] = videobuf_alloc(q);
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if (q->bufs[i] == NULL)
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break;
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q->bufs[i]->i = i;
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q->bufs[i]->input = UNSET;
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q->bufs[i]->memory = memory;
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q->bufs[i]->bsize = bsize;
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switch (memory) {
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case V4L2_MEMORY_MMAP:
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q->bufs[i]->boff = bsize * i;
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break;
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case V4L2_MEMORY_USERPTR:
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case V4L2_MEMORY_OVERLAY:
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/* nothing */
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break;
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}
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}
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if (!i)
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return -ENOMEM;
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dprintk(1,"mmap setup: %d buffers, %d bytes each\n",
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i, bsize);
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return i;
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}
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int videobuf_mmap_free(struct videobuf_queue *q)
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{
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int i;
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int rc;
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if (!q)
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return 0;
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MAGIC_CHECK(q->int_ops->magic,MAGIC_QTYPE_OPS);
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rc = CALL(q,mmap_free,q);
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if (rc<0)
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return rc;
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for (i = 0; i < VIDEO_MAX_FRAME; i++) {
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if (NULL == q->bufs[i])
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continue;
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q->ops->buf_release(q,q->bufs[i]);
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kfree(q->bufs[i]);
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q->bufs[i] = NULL;
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}
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return rc;
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}
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int videobuf_mmap_mapper(struct videobuf_queue *q,
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struct vm_area_struct *vma)
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{
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@ -989,8 +1058,8 @@ EXPORT_SYMBOL_GPL(videobuf_dqbuf);
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EXPORT_SYMBOL_GPL(videobuf_streamon);
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EXPORT_SYMBOL_GPL(videobuf_streamoff);
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EXPORT_SYMBOL_GPL(videobuf_read_start);
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EXPORT_SYMBOL_GPL(videobuf_read_stop);
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EXPORT_SYMBOL_GPL(videobuf_stop);
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EXPORT_SYMBOL_GPL(videobuf_read_stream);
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EXPORT_SYMBOL_GPL(videobuf_read_one);
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EXPORT_SYMBOL_GPL(videobuf_poll_stream);
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@ -208,6 +208,8 @@ int videobuf_cgmbuf(struct videobuf_queue *q,
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int videobuf_streamon(struct videobuf_queue *q);
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int videobuf_streamoff(struct videobuf_queue *q);
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void videobuf_stop(struct videobuf_queue *q);
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int videobuf_read_start(struct videobuf_queue *q);
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void videobuf_read_stop(struct videobuf_queue *q);
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ssize_t videobuf_read_stream(struct videobuf_queue *q,
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