Re: [PATCHv9 19/25] v4l: vb2: add buffer exporting via dmabuf
From: Hans Verkuil <hidden>
Date: 2012-10-06 12:22:40
Also in:
dri-devel
On Tue October 2 2012 16:27:30 Tomasz Stanislawski wrote:
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This patch adds extension to videobuf2-core. It allow to export a mmap buffer as a file descriptor. Signed-off-by: Tomasz Stanislawski <redacted> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> --- drivers/media/video/videobuf2-core.c | 82 ++++++++++++++++++++++++++++++++++ include/media/videobuf2-core.h | 4 ++ 2 files changed, 86 insertions(+)diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c index 05da3b4..a97815b 100644 --- a/drivers/media/video/videobuf2-core.c +++ b/drivers/media/video/videobuf2-core.c
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@@ -2455,6 +2528,15 @@ int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i) } EXPORT_SYMBOL_GPL(vb2_ioctl_streamoff); +int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p) +{ + struct video_device *vdev = video_devdata(file); + + /* No need to call vb2_queue_is_busy(), anyone can export buffers. */
After thinking about this some more I'm not so sure we should allow this. Exporting a buffer also means that the memory can't be freed as long as the exported filehandle remains open. That means that it is possible to make a malicious application that exports the buffers and never frees them, which can cause havoc. I think that only the filehandle that called REQBUFS/CREATE_BUFS should be allowed to export buffers. What do you think? Regards, Hans
+ return vb2_expbuf(vdev->queue, p); +} +EXPORT_SYMBOL_GPL(vb2_ioctl_expbuf); + /* v4l2_file_operations helpers */ int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma)