[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>

diff --git a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
index e287c8f..4165e7b 100644 (file)
--- a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml
@@ -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>

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index b19b306..57ba131 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -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);

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 646f08f..33d3871 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -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;
 

diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index bd8218b..941055e 100644 (file)
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -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);