v4l2-mem2mem presently does not allow VIDIOC_REQBUFS to destroy
outstanding buffers if the queue is of type V4L2_MEMORY_MMAP, and if the
buffers are considered "in use". This is different behavior than for
other memory types, and prevents us for deallocating buffers in a few
cases:
* In the case that there are outstanding mmap()ed views on the buffer,
refcounting on the videobuf2 buffer backing the vm_area will track
lifetime appropriately,
* In the case that the buffer has been exported as a DMABUF, refcounting
on the videobuf2 bufer backing the DMABUF will track lifetime
appropriately.
Remove the specific check for type V4L2_MEMOMRY_MMAP when freeing all
buffers through VIDIOC_REQBUFS.
Signed-off-by: John Sheu <sheu@xxxxxxxxxx>
---
drivers/media/v4l2-core/videobuf2-core.c | 26 +-------------------------
1 file changed, 1 insertion(+), 25 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 8e6695c9..5b6f9da6 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -414,8 +414,7 @@ static int __verify_length(struct vb2_buffer *vb, const struct v4l2_buffer *b)
}
/**
- * __buffer_in_use() - return true if the buffer is in use and
- * the queue cannot be freed (by the means of REQBUFS(0)) call
+ * __buffer_in_use() - return true if the buffer is in use.
*/
static bool __buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb)
{
@@ -435,20 +434,6 @@ static bool __buffer_in_use(struct vb2_queue *q, struct vb2_buffer *vb)
}
/**
- * __buffers_in_use() - return true if any buffers on the queue are in use and
- * the queue cannot be freed (by the means of REQBUFS(0)) call
- */
-static bool __buffers_in_use(struct vb2_queue *q)
-{
- unsigned int buffer;
- for (buffer = 0; buffer < q->num_buffers; ++buffer) {
- if (__buffer_in_use(q, q->bufs[buffer]))
- return true;
- }
- return false;
-}
-
-/**
* __fill_v4l2_buffer() - fill in a struct v4l2_buffer with information to be
* returned to userspace
*/
@@ -681,15 +666,6 @@ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
}
if (req->count == 0 || q->num_buffers != 0 || q->memory != req->memory) {
- /*
- * We already have buffers allocated, so first check if they
- * are not in use and can be freed.
- */
- if (q->memory == V4L2_MEMORY_MMAP && __buffers_in_use(q)) {
- dprintk(1, "reqbufs: memory in use, cannot free\n");
- return -EBUSY;
- }
-
ret = __vb2_queue_free(q, q->num_buffers);
if (ret)
return ret;
--
1.9.0.279.gdc9e3eb
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