media: videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag

This patch lets user-space request a non-coherent 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 byte of a 4 byte ->reserved[1] member of struct
 v4l2_requestbuffers. The struct, thus, now has reserved 3 bytes.

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>

2 files changed, 10 insertions, 3 deletions

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 47aff3b19742..8176769a89fa 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -126,6 +126,9 @@ 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 {
@@ -134,7 +137,8 @@ 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 get_v4l2_format32(struct v4l2_format *p64,
@@ -182,6 +186,8 @@ static int get_v4l2_create32(struct v4l2_create_buffers *p64,
 	if (copy_from_user(p64, p32,
 			   offsetof(struct v4l2_create_buffers32, format)))
 		return -EFAULT;
+	if (copy_from_user(&p64->flags, &p32->flags, sizeof(p32->flags)))
+		return -EFAULT;
 	return get_v4l2_format32(&p64->format, &p32->format);
 }
 
@@ -227,6 +233,7 @@ static int put_v4l2_create32(struct v4l2_create_buffers *p64,
 	if (copy_to_user(p32, p64,
 			 offsetof(struct v4l2_create_buffers32, format)) ||
 	    put_user(p64->capabilities, &p32->capabilities) ||
+	    put_user(p64->flags, &p32->flags) ||
 	    copy_to_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 bc83d23ce25d..31d0109ce5a8 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2024,7 +2024,7 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops,
 	if (ret)
 		return ret;
 
-	CLEAR_AFTER_FIELD(p, capabilities);
+	CLEAR_AFTER_FIELD(p, flags);
 
 	return ops->vidioc_reqbufs(file, fh, p);
 }
@@ -2065,7 +2065,7 @@ 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);