[RFC PATCH v2 11/13] io_uring: Define the zctap iov[] returned to the user.

[Jonathan Lemon <jonathan.lemon@gmail.com>]

When performing a ZC receive, instead of returning data directly
to the user, an iov[] structure is returned referencing the data
in user space.

The application locates the base address of the data by performing
address computations on bgid:bid.  The off/len applies to the base
address, resulting in the data segment.

The bgid:bid identifying the buffer should later be placed in the
ifq's fill ring, which returns the buffer back to the kernel.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
---
 include/uapi/linux/io_uring.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index d406d21e8c38..c50c63053f13 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -681,6 +681,14 @@ struct io_uring_ifq_req {
 	__u16	__pad[2];
 };
 
+struct io_uring_zctap_iov {
+	__u32	off;
+	__u32	len;
+	__u16	bgid;
+	__u16	bid;
+	__u16	resv[2];
+};
+
 #ifdef __cplusplus
 }
 #endif
-- 
2.30.2