[PATCH v4 1/2] splice: add splice(2) helpers

[Pavel Begunkov <asml.silence@xxxxxxxxx>]

Add splice helpers and update io_uring.h

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
 src/include/liburing.h          | 12 ++++++++++++
 src/include/liburing/io_uring.h | 14 +++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/include/liburing.h b/src/include/liburing.h
index b8bcdf5..7edd4f1 100644
--- a/src/include/liburing.h
+++ b/src/include/liburing.h
@@ -191,6 +191,18 @@ static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
 	sqe->__pad2[0] = sqe->__pad2[1] = sqe->__pad2[2] = 0;
 }
 
+static inline void io_uring_prep_splice(struct io_uring_sqe *sqe,
+					int fd_in, loff_t off_in,
+					int fd_out, loff_t off_out,
+					unsigned int nbytes,
+					unsigned int splice_flags)
+{
+	io_uring_prep_rw(IORING_OP_SPLICE, sqe, fd_out, (void *)off_in,
+			 nbytes, off_out);
+	sqe->splice_fd_in = fd_in;
+	sqe->splice_flags = splice_flags;
+}
+
 static inline void io_uring_prep_readv(struct io_uring_sqe *sqe, int fd,
 				       const struct iovec *iovecs,
 				       unsigned nr_vecs, off_t offset)
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
index 7e7c2d9..a3d5e25 100644
--- a/src/include/liburing/io_uring.h
+++ b/src/include/liburing/io_uring.h
@@ -23,7 +23,10 @@ struct io_uring_sqe {
 		__u64	off;	/* offset into file */
 		__u64	addr2;
 	};
-	__u64	addr;		/* pointer to buffer or iovecs */
+	union {
+		__u64	addr;	/* pointer to buffer or iovecs */
+		__u64	splice_off_in;
+	};
 	__u32	len;		/* buffer size or number of iovecs */
 	union {
 		__kernel_rwf_t	rw_flags;
@@ -37,6 +40,7 @@ struct io_uring_sqe {
 		__u32		open_flags;
 		__u32		statx_flags;
 		__u32		fadvise_advice;
+		__u32		splice_flags;
 	};
 	__u64	user_data;	/* data to be passed back at completion time */
 	union {
@@ -45,6 +49,7 @@ struct io_uring_sqe {
 			__u16	buf_index;
 			/* personality to use, if used */
 			__u16	personality;
+			__s32	splice_fd_in;
 		};
 		__u64	__pad2[3];
 	};
@@ -113,6 +118,7 @@ enum {
 	IORING_OP_RECV,
 	IORING_OP_OPENAT2,
 	IORING_OP_EPOLL_CTL,
+	IORING_OP_SPLICE,
 
 	/* this goes last, obviously */
 	IORING_OP_LAST,
@@ -128,6 +134,12 @@ enum {
  */
 #define IORING_TIMEOUT_ABS	(1U << 0)
 
+/*
+ * sqe->splice_flags
+ * extends splice(2) flags
+ */
+#define SPLICE_F_FD_IN_FIXED	(1U << 31) /* the last bit of __u32 */
+
 /*
  * IO completion data structure (Completion Queue Entry)
  */
-- 
2.24.0