media: videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT flag

This patch lets user-space to request a non-consistent memory
allocation during CREATE_BUFS and REQBUFS ioctl calls.

= CREATE_BUFS

  struct v4l2_create_buffers has seven 4-byte reserved areas,
  so reserved[0] is renamed to ->flags. The struct, thus, now
  has six reserved 4-byte regions.

= CREATE_BUFS32

  struct v4l2_create_buffers32 has seven 4-byte reserved areas,
  so reserved[0] is renamed to ->flags. The struct, thus, now
  has six reserved 4-byte regions.

= REQBUFS

 We use one bit of a ->reserved[1] member of struct v4l2_requestbuffers,
 which is now renamed to ->flags. Unlike v4l2_create_buffers, struct
 v4l2_requestbuffers does not have enough reserved room. Therefore for
 backward compatibility  ->reserved and ->flags were put into anonymous
 union.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
index e1afc5b..f2a7028 100644 (file)
--- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
@@ -121,7 +121,12 @@ than the number requested.
        other changes, then set ``count`` to 0, ``memory`` to
        ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
     * - __u32
-      - ``reserved``\ [7]
+      - ``flags``
+      - Specifies additional buffer management attributes.
+       See :ref:`memory-flags`.
+
+    * - __u32
+      - ``reserved``\ [6]
       - A place holder for future extensions. Drivers and applications
        must set the array to zero.
 

diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
index 96a5979..75d894d 100644 (file)
--- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
@@ -112,10 +112,17 @@ aborting or finishing any DMA in progress, an implicit
        ``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
        free any previously allocated buffers, so this is typically something
        that will be done at the start of the application.
+    * - union {
+      - (anonymous)
+    * - __u32
+      - ``flags``
+      - Specifies additional buffer management attributes.
+       See :ref:`memory-flags`.
     * - __u32
       - ``reserved``\ [1]
-      - A place holder for future extensions. Drivers and applications
-       must set the array to zero.
+      - Kept for backwards compatibility. Use ``flags`` instead.
+    * - }
+      -
 
 .. tabularcolumns:: |p{6.1cm}|p{2.2cm}|p{8.7cm}|
 

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 0fdcf90..626c4db 100644 (file)
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -694,6 +694,9 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
        unsigned int i;
        int ret;
 
+       if (flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
+               consistent_mem = false;
+
        if (q->streaming) {
                dprintk(1, "streaming active\n");
                return -EBUSY;
@@ -837,6 +840,9 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
        bool consistent_mem = true;
        int ret;
 
+       if (flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
+               consistent_mem = false;
+
        if (q->num_buffers == VB2_MAX_FRAME) {
                dprintk(1, "maximum number of buffers already allocated\n");
                return -ENOBUFS;

diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 26a3ec3..559a229 100644 (file)
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -718,12 +718,22 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
 #endif
 }
 
+static void clear_consistency_attr(struct vb2_queue *q,
+                                  int memory,
+                                  unsigned int *flags)
+{
+       if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP)
+               *flags &= ~V4L2_FLAG_MEMORY_NON_CONSISTENT;
+}
+
 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
 {
        int ret = vb2_verify_memory_type(q, req->memory, req->type);
 
        fill_buf_caps(q, &req->capabilities);
-       return ret ? ret : vb2_core_reqbufs(q, req->memory, 0, &req->count);
+       clear_consistency_attr(q, req->memory, &req->flags);
+       return ret ? ret : vb2_core_reqbufs(q, req->memory,
+                                           req->flags, &req->count);
 }
 EXPORT_SYMBOL_GPL(vb2_reqbufs);
 
@@ -755,6 +765,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
        unsigned i;
 
        fill_buf_caps(q, &create->capabilities);
+       clear_consistency_attr(q, create->memory, &create->flags);
        create->index = q->num_buffers;
        if (create->count == 0)
                return ret != -EBUSY ? ret : 0;
@@ -797,8 +808,11 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
        for (i = 0; i < requested_planes; i++)
                if (requested_sizes[i] == 0)
                        return -EINVAL;
-       return ret ? ret : vb2_core_create_bufs(q, create->memory, 0,
-               &create->count, requested_planes, requested_sizes);
+       return ret ? ret : vb2_core_create_bufs(q, create->memory,
+                                               create->flags,
+                                               &create->count,
+                                               requested_planes,
+                                               requested_sizes);
 }
 EXPORT_SYMBOL_GPL(vb2_create_bufs);
 
@@ -969,11 +983,12 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
        int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
 
        fill_buf_caps(vdev->queue, &p->capabilities);
+       clear_consistency_attr(vdev->queue, p->memory, &p->flags);
        if (res)
                return res;
        if (vb2_queue_is_busy(vdev, file))
                return -EBUSY;
-       res = vb2_core_reqbufs(vdev->queue, p->memory, 0, &p->count);
+       res = vb2_core_reqbufs(vdev->queue, p->memory, p->flags, &p->count);
        /* If count == 0, then the owner has released all buffers and he
           is no longer owner of the queue. Otherwise we have a new owner. */
        if (res == 0)
@@ -991,6 +1006,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
 
        p->index = vdev->queue->num_buffers;
        fill_buf_caps(vdev->queue, &p->capabilities);
+       clear_consistency_attr(vdev->queue, p->memory, &p->flags);
        /*
         * If count == 0, then just check if memory and type are valid.
         * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index a99e82e..593bcf6 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -246,6 +246,9 @@ struct v4l2_format32 {
  * @memory:    buffer memory type
  * @format:    frame format, for which buffers are requested
  * @capabilities: capabilities of this buffer type.
+ * @flags:     additional buffer management attributes (ignored unless the
+ *             queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability and
+ *             configured for MMAP streaming I/O).
  * @reserved:  future extensions
  */
 struct v4l2_create_buffers32 {
@@ -254,7 +257,8 @@ struct v4l2_create_buffers32 {
        __u32                   memory; /* enum v4l2_memory */
        struct v4l2_format32    format;
        __u32                   capabilities;
-       __u32                   reserved[7];
+       __u32                   flags;
+       __u32                   reserved[6];
 };
 
 static int __bufsize_v4l2_format(struct v4l2_format32 __user *p32, u32 *size)
@@ -355,7 +359,8 @@ static int get_v4l2_create32(struct v4l2_create_buffers __user *p64,
 {
        if (!access_ok(p32, sizeof(*p32)) ||
            copy_in_user(p64, p32,
-                        offsetof(struct v4l2_create_buffers32, format)))
+                        offsetof(struct v4l2_create_buffers32, format)) ||
+           assign_in_user(&p64->flags, &p32->flags))
                return -EFAULT;
        return __get_v4l2_format32(&p64->format, &p32->format,
                                   aux_buf, aux_space);
@@ -417,6 +422,7 @@ static int put_v4l2_create32(struct v4l2_create_buffers __user *p64,
            copy_in_user(p32, p64,
                         offsetof(struct v4l2_create_buffers32, format)) ||
            assign_in_user(&p32->capabilities, &p64->capabilities) ||
+           assign_in_user(&p32->flags, &p64->flags) ||
            copy_in_user(p32->reserved, p64->reserved, sizeof(p64->reserved)))
                return -EFAULT;
        return __put_v4l2_format32(&p64->format, &p32->format);

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 2322f08..02bfef0 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2038,9 +2038,6 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops,
 
        if (ret)
                return ret;
-
-       CLEAR_AFTER_FIELD(p, capabilities);
-
        return ops->vidioc_reqbufs(file, fh, p);
 }
 
@@ -2080,7 +2077,7 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
        if (ret)
                return ret;
 
-       CLEAR_AFTER_FIELD(create, capabilities);
+       CLEAR_AFTER_FIELD(create, flags);
 
        v4l_sanitize_format(&create->format);
 

diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 34ba101..fec2607 100644 (file)
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -946,7 +946,10 @@ struct v4l2_requestbuffers {
        __u32                   type;           /* enum v4l2_buf_type */
        __u32                   memory;         /* enum v4l2_memory */
        __u32                   capabilities;
-       __u32                   reserved[1];
+       union {
+               __u32           flags;
+               __u32           reserved[1];
+       };
 };
 
 /* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */
@@ -2450,6 +2453,9 @@ struct v4l2_dbg_chip_info {
  * @memory:    enum v4l2_memory; buffer memory type
  * @format:    frame format, for which buffers are requested
  * @capabilities: capabilities of this buffer type.
+ * @flags:     additional buffer management attributes (ignored unless the
+ *             queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability
+ *             and configured for MMAP streaming I/O).
  * @reserved:  future extensions
  */
 struct v4l2_create_buffers {
@@ -2458,7 +2464,8 @@ struct v4l2_create_buffers {
        __u32                   memory;
        struct v4l2_format      format;
        __u32                   capabilities;
-       __u32                   reserved[7];
+       __u32                   flags;
+       __u32                   reserved[6];
 };
 
 /*