Match const signatures in io_uring_prep_* to native functions

io_uring_prep_{readv,writev,read_fixed,write_fixed}() take
non-const arguments that are const in the native functions
that they mimic. Make those arguments const.

Signed-off-by: Ian Gulliver <git@flamingcow.io>

src/liburing.h

@@ -106,7 +106,8 @@ static inline void *io_uring_cqe_get_data(struct io_uring_cqe *cqe)
 }
 
 static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
-				    void *addr, unsigned len, off_t offset)
+				    const void *addr, unsigned len,
+				    off_t offset)
 {
 	memset(sqe, 0, sizeof(*sqe));
 	sqe->opcode = op;
@@ -117,8 +118,8 @@ static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
 }
 
 static inline void io_uring_prep_readv(struct io_uring_sqe *sqe, int fd,
-				       struct iovec *iovecs, unsigned nr_vecs,
-				       off_t offset)
+				       const struct iovec *iovecs,
+				       unsigned nr_vecs, off_t offset)
 {
 	io_uring_prep_rw(IORING_OP_READV, sqe, fd, iovecs, nr_vecs, offset);
 }
@@ -131,14 +132,14 @@ static inline void io_uring_prep_read_fixed(struct io_uring_sqe *sqe, int fd,
 }
 
 static inline void io_uring_prep_writev(struct io_uring_sqe *sqe, int fd,
-				        struct iovec *iovecs, unsigned nr_vecs,
-					off_t offset)
+					const struct iovec *iovecs,
+					unsigned nr_vecs, off_t offset)
 {
 	io_uring_prep_rw(IORING_OP_WRITEV, sqe, fd, iovecs, nr_vecs, offset);
 }
 
 static inline void io_uring_prep_write_fixed(struct io_uring_sqe *sqe, int fd,
-					     void *buf, unsigned nbytes,
+					     const void *buf, unsigned nbytes,
 					     off_t offset)
 {
 	io_uring_prep_rw(IORING_OP_WRITE_FIXED, sqe, fd, buf, nbytes, offset);