diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0259-media-vb2-Allow-reqbufs-0-with-in-use-MMAP-buffers.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0259-media-vb2-Allow-reqbufs-0-with-in-use-MMAP-buffers.patch | 76 |
1 files changed, 0 insertions, 76 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0259-media-vb2-Allow-reqbufs-0-with-in-use-MMAP-buffers.patch b/target/linux/brcm2708/patches-4.19/950-0259-media-vb2-Allow-reqbufs-0-with-in-use-MMAP-buffers.patch deleted file mode 100644 index 8bc16911ca..0000000000 --- a/target/linux/brcm2708/patches-4.19/950-0259-media-vb2-Allow-reqbufs-0-with-in-use-MMAP-buffers.patch +++ /dev/null @@ -1,76 +0,0 @@ -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] 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 |