media: videodev2.h: Add request_fd field to v4l2_buffer

When queuing buffers allow for passing the request that should
be associated with this buffer.

If V4L2_BUF_FLAG_REQUEST_FD is set, then request_fd is used as
the file descriptor.

If a buffer is stored in a request, but not yet queued to the
driver, then V4L2_BUF_FLAG_IN_REQUEST is set.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/common/videobuf2/videobuf2-v4l2.c

@@ -384,7 +384,7 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, void *pb)
 	b->timecode = vbuf->timecode;
 	b->sequence = vbuf->sequence;
 	b->reserved2 = 0;
-	b->reserved = 0;
+	b->request_fd = 0;
 
 	if (q->is_multiplanar) {
 		/*

drivers/media/usb/cpia2/cpia2_v4l.c

@@ -949,7 +949,7 @@ static int cpia2_dqbuf(struct file *file, void *fh, struct v4l2_buffer *buf)
 	buf->m.offset = cam->buffers[buf->index].data - cam->frame_buffer;
 	buf->length = cam->frame_size;
 	buf->reserved2 = 0;
-	buf->reserved = 0;
+	buf->request_fd = 0;
 	memset(&buf->timecode, 0, sizeof(buf->timecode));
 
 	DBG("DQBUF #%d status:%d seq:%d length:%d\n", buf->index,

drivers/media/v4l2-core/v4l2-compat-ioctl32.c

@@ -482,7 +482,7 @@ struct v4l2_buffer32 {
 	} m;
 	__u32			length;
 	__u32			reserved2;
-	__u32			reserved;
+	__s32			request_fd;
 };
 
 static int get_v4l2_plane32(struct v4l2_plane __user *p64,
@@ -581,6 +581,7 @@ static int get_v4l2_buffer32(struct v4l2_buffer __user *p64,
 {
 	u32 type;
 	u32 length;
+	s32 request_fd;
 	enum v4l2_memory memory;
 	struct v4l2_plane32 __user *uplane32;
 	struct v4l2_plane __user *uplane;
@@ -595,7 +596,9 @@ static int get_v4l2_buffer32(struct v4l2_buffer __user *p64,
 	    get_user(memory, &p32->memory) ||
 	    put_user(memory, &p64->memory) ||
 	    get_user(length, &p32->length) ||
-	    put_user(length, &p64->length))
+	    put_user(length, &p64->length) ||
+	    get_user(request_fd, &p32->request_fd) ||
+	    put_user(request_fd, &p64->request_fd))
 		return -EFAULT;
 
 	if (V4L2_TYPE_IS_OUTPUT(type))
@@ -699,7 +702,7 @@ static int put_v4l2_buffer32(struct v4l2_buffer __user *p64,
 	    copy_in_user(&p32->timecode, &p64->timecode, sizeof(p64->timecode)) ||
 	    assign_in_user(&p32->sequence, &p64->sequence) ||
 	    assign_in_user(&p32->reserved2, &p64->reserved2) ||
-	    assign_in_user(&p32->reserved, &p64->reserved) ||
+	    assign_in_user(&p32->request_fd, &p64->request_fd) ||
 	    get_user(length, &p64->length) ||
 	    put_user(length, &p32->length))
 		return -EFAULT;

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -474,13 +474,13 @@ static void v4l_print_buffer(const void *arg, bool write_only)
 	const struct v4l2_plane *plane;
 	int i;
 
-	pr_cont("%02ld:%02d:%02d.%08ld index=%d, type=%s, flags=0x%08x, field=%s, sequence=%d, memory=%s",
+	pr_cont("%02ld:%02d:%02d.%08ld index=%d, type=%s, request_fd=%d, flags=0x%08x, field=%s, sequence=%d, memory=%s",
 			p->timestamp.tv_sec / 3600,
 			(int)(p->timestamp.tv_sec / 60) % 60,
 			(int)(p->timestamp.tv_sec % 60),
 			(long)p->timestamp.tv_usec,
 			p->index,
-			prt_names(p->type, v4l2_type_names),
+			prt_names(p->type, v4l2_type_names), p->request_fd,
 			p->flags, prt_names(p->field, v4l2_field_names),
 			p->sequence, prt_names(p->memory, v4l2_memory_names));
 

include/uapi/linux/videodev2.h

@@ -917,6 +917,7 @@ struct v4l2_plane {
  * @length:	size in bytes of the buffer (NOT its payload) for single-plane
  *		buffers (when type != *_MPLANE); number of elements in the
  *		planes array for multi-plane buffers
+ * @request_fd: fd of the request that this buffer should use
  *
  * Contains data exchanged by application and driver using one of the Streaming
  * I/O methods.
@@ -941,7 +942,10 @@ struct v4l2_buffer {
 	} m;
 	__u32			length;
 	__u32			reserved2;
-	__u32			reserved;
+	union {
+		__s32		request_fd;
+		__u32		reserved;
+	};
 };
 
 /*  Flags for 'flags' field */
@@ -959,6 +963,8 @@ struct v4l2_buffer {
 #define V4L2_BUF_FLAG_BFRAME			0x00000020
 /* Buffer is ready, but the data contained within is corrupted. */
 #define V4L2_BUF_FLAG_ERROR			0x00000040
+/* Buffer is added to an unqueued request */
+#define V4L2_BUF_FLAG_IN_REQUEST		0x00000080
 /* timecode field is valid */
 #define V4L2_BUF_FLAG_TIMECODE			0x00000100
 /* Buffer is prepared for queuing */
@@ -977,6 +983,8 @@ struct v4l2_buffer {
 #define V4L2_BUF_FLAG_TSTAMP_SRC_SOE		0x00010000
 /* mem2mem encoder/decoder */
 #define V4L2_BUF_FLAG_LAST			0x00100000
+/* request_fd is valid */
+#define V4L2_BUF_FLAG_REQUEST_FD		0x00800000
 
 /**
  * struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor