You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
77 lines
2.9 KiB
Diff
77 lines
2.9 KiB
Diff
From cf6f8129b6af78116e00b1d781e0bcc8c4b73890 Mon Sep 17 00:00:00 2001
|
|
From: John Sheu <sheu@chromium.org>
|
|
Date: Thu, 15 Oct 2015 18:05:25 +0900
|
|
Subject: [PATCH 282/806] media: vb2: Allow reqbufs(0) with "in use" MMAP
|
|
buffers
|
|
|
|
Videobuf2 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 from deallocating buffers in following two cases:
|
|
|
|
1) There are outstanding mmap()ed views on the buffer. However even if
|
|
we put the buffer in reqbufs(0), there will be remaining references,
|
|
due to vma .open/close() adjusting vb2 buffer refcount appropriately.
|
|
This means that the buffer will be in fact freed only when the last
|
|
mmap()ed view is unmapped.
|
|
|
|
2) Buffer has been exported as a DMABUF. Refcount of the vb2 buffer
|
|
is managed properly by VB2 DMABUF ops, i.e. incremented on DMABUF
|
|
get and decremented on DMABUF release. This means that the buffer
|
|
will be alive until all importers release it.
|
|
|
|
Considering both cases above, there does not seem to be any need to
|
|
prevent reqbufs(0) operation, because buffer lifetime is already
|
|
properly managed by both mmap() and DMABUF code paths. Let's remove it
|
|
and allow userspace freeing the queue (and potentially allocating a new
|
|
one) even though old buffers might be still in processing.
|
|
|
|
Signed-off-by: John Sheu <sheu@chromium.org>
|
|
Reviewed-by: Pawel Osciak <posciak@chromium.org>
|
|
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
|
|
Signed-off-by: Tomasz Figa <tfiga@chromium.org>
|
|
---
|
|
.../media/common/videobuf2/videobuf2-core.c | 23 -------------------
|
|
1 file changed, 23 deletions(-)
|
|
|
|
--- a/drivers/media/common/videobuf2/videobuf2-core.c
|
|
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
|
|
@@ -554,20 +554,6 @@ bool vb2_buffer_in_use(struct vb2_queue
|
|
}
|
|
EXPORT_SYMBOL(vb2_buffer_in_use);
|
|
|
|
-/*
|
|
- * __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 (vb2_buffer_in_use(q, q->bufs[buffer]))
|
|
- return true;
|
|
- }
|
|
- return false;
|
|
-}
|
|
-
|
|
void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb)
|
|
{
|
|
call_void_bufop(q, fill_user_buffer, q->bufs[index], pb);
|
|
@@ -679,16 +665,7 @@ int vb2_core_reqbufs(struct vb2_queue *q
|
|
|
|
if (*count == 0 || q->num_buffers != 0 ||
|
|
(q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory)) {
|
|
- /*
|
|
- * We already have buffers allocated, so first check if they
|
|
- * are not in use and can be freed.
|
|
- */
|
|
mutex_lock(&q->mmap_lock);
|
|
- if (q->memory == VB2_MEMORY_MMAP && __buffers_in_use(q)) {
|
|
- mutex_unlock(&q->mmap_lock);
|
|
- dprintk(1, "memory in use, cannot free\n");
|
|
- return -EBUSY;
|
|
- }
|
|
|
|
/*
|
|
* Call queue_cancel to clean up any buffers in the PREPARED or
|