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[media] videobuf2: Add support for file access mode flags for DMABUF exporting 

Currently it is not possible for userspace to map a DMABUF exported buffer
with write permissions. This patch allows to also pass O_RDONLY/O_RDWR when
exporting the buffer, so that userspace may map it with write permissions.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Philipp Zabel 2013-05-21 05:11:35 -03:00 committed by Mauro Carvalho Chehab
parent d8eec74a22
commit ea3aba8482
4 changed files with 12 additions and 10 deletions
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8
Documentation/DocBook/media/v4l/vidioc-expbuf.xml
View File

@ -73,7 +73,8 @@ range from zero to the maximal number of valid planes for the currently active
format. For the single-planar API, applications must set <structfield> plane
</structfield> to zero. Additional flags may be posted in the <structfield>
flags </structfield> field. Refer to a manual for open() for details.
Currently only O_CLOEXEC is supported. All other fields must be set to zero.
Currently only O_CLOEXEC, O_RDONLY, O_WRONLY, and O_RDWR are supported. All
other fields must be set to zero.
In the case of multi-planar API, every plane is exported separately using
multiple <constant> VIDIOC_EXPBUF </constant> calls. </para>
@ -170,8 +171,9 @@ multi-planar API. Otherwise this value must be set to zero. </entry>
<entry>__u32</entry>
<entry><structfield>flags</structfield></entry>
<entry>Flags for the newly created file, currently only <constant>
O_CLOEXEC </constant> is supported, refer to the manual of open() for more
details.</entry>
O_CLOEXEC </constant>, <constant>O_RDONLY</constant>, <constant>O_WRONLY
</constant>, and <constant>O_RDWR</constant> are supported, refer to the manual
of open() for more details.</entry>
</row>
<row>
<entry>__s32</entry>

8
drivers/media/v4l2-core/videobuf2-core.c
View File

@ -1824,8 +1824,8 @@ int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb)
return -EINVAL;
}
if (eb->flags & ~O_CLOEXEC) {
dprintk(1, "Queue does support only O_CLOEXEC flag\n");
if (eb->flags & ~(O_CLOEXEC | O_ACCMODE)) {
dprintk(1, "Queue does support only O_CLOEXEC and access mode flags\n");
return -EINVAL;
}
@ -1848,14 +1848,14 @@ int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb)
vb_plane = &vb->planes[eb->plane];
dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv);
dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv, eb->flags & O_ACCMODE);
if (IS_ERR_OR_NULL(dbuf)) {
dprintk(1, "Failed to export buffer %d, plane %d\n",
eb->index, eb->plane);
return -EINVAL;
}
ret = dma_buf_fd(dbuf, eb->flags);
ret = dma_buf_fd(dbuf, eb->flags & ~O_ACCMODE);
if (ret < 0) {
dprintk(3, "buffer %d, plane %d failed to export (%d)\n",
eb->index, eb->plane, ret);

4
drivers/media/v4l2-core/videobuf2-dma-contig.c
View File

@ -393,7 +393,7 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
return sgt;
}
static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
{
struct vb2_dc_buf *buf = buf_priv;
struct dma_buf *dbuf;
@ -404,7 +404,7 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv)
if (WARN_ON(!buf->sgt_base))
return NULL;
dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0);
dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, flags);
if (IS_ERR(dbuf))
return NULL;

2
include/media/videobuf2-core.h
View File

@ -83,7 +83,7 @@ struct vb2_fileio_data;
struct vb2_mem_ops {
void *(*alloc)(void *alloc_ctx, unsigned long size, gfp_t gfp_flags);
void (*put)(void *buf_priv);
struct dma_buf *(*get_dmabuf)(void *buf_priv);
struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write);