[PATCH 05/10] media: videobuf2: Allow exporting of a struct dmabuf
From: Jai Luthra <hidden>
Date: 2026-01-13 09:07:59
Also in:
linux-media
Subsystem:
media input infrastructure (v4l/dvb), the rest, videobuf2 framework · Maintainers:
Mauro Carvalho Chehab, Linus Torvalds, Tomasz Figa, Marek Szyprowski
From: Dave Stevenson <redacted> videobuf2 only allowed exporting a dmabuf as a file descriptor, but there are instances where having the struct dma_buf is useful within the kernel. Split the current implementation into two, one step which exports a struct dma_buf, and the second which converts that into an fd. Signed-off-by: Dave Stevenson <redacted> Signed-off-by: Jai Luthra <redacted> --- drivers/media/common/videobuf2/videobuf2-core.c | 21 ++++++++++++++++++--- include/media/videobuf2-core.h | 15 +++++++++++++++ 2 files changed, 33 insertions(+), 3 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 2df566f409b65eb99fa7fbe308b8e3afe1bdcbca..f316864d99fc5c5abb2e5a27779cbc371c1a211d 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c@@ -2431,11 +2431,11 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, return 0; } -int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, - struct vb2_buffer *vb, unsigned int plane, unsigned int flags) +int vb2_core_expbuf_dmabuf(struct vb2_queue *q, unsigned int type, + struct vb2_buffer *vb, unsigned int plane, + unsigned int flags, struct dma_buf **dmabuf) { struct vb2_plane *vb_plane; - int ret; struct dma_buf *dbuf; if (q->memory != VB2_MEMORY_MMAP) {
@@ -2480,6 +2480,21 @@ int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, return -EINVAL; } + *dmabuf = dbuf; + return 0; +} +EXPORT_SYMBOL_GPL(vb2_core_expbuf_dmabuf); + +int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, + struct vb2_buffer *vb, unsigned int plane, unsigned int flags) +{ + struct dma_buf *dbuf; + int ret; + + ret = vb2_core_expbuf_dmabuf(q, type, vb, plane, flags, &dbuf); + if (ret) + return ret; + ret = dma_buf_fd(dbuf, flags & ~O_ACCMODE); if (ret < 0) { dprintk(q, 3, "buffer %d, plane %d failed to export (%d)\n",
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 9b02aeba41089c42b552998b49f27906dc70eeae..c75b4f14581a353d8dbe68d8bedd2b2ee86934d2 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h@@ -967,6 +967,21 @@ int vb2_core_streamon(struct vb2_queue *q, unsigned int type); */ int vb2_core_streamoff(struct vb2_queue *q, unsigned int type); +/** + * vb2_core_expbuf_dmabuf() - Export a buffer as a dma_buf structure + * @q: videobuf2 queue + * @type: buffer type + * @index: id number of the buffer + * @plane: index of the plane to be exported, 0 for single plane queues + * @flags: flags for newly created file, currently only O_CLOEXEC is + * supported, refer to manual of open syscall for more details + * @dmabuf: Returns the dmabuf pointer + * + */ +int vb2_core_expbuf_dmabuf(struct vb2_queue *q, unsigned int type, + struct vb2_buffer *vb, unsigned int plane, + unsigned int flags, struct dma_buf **dmabuf); + /** * vb2_core_expbuf() - Export a buffer as a file descriptor. * @q: pointer to &struct vb2_queue with videobuf2 queue.
--
2.52.0