[PATCH liburing v2] liburing: add helpers for direct open/accept

[Pavel Begunkov <asml.silence@xxxxxxxxx>]

We allow openat/openat2/accept to place new files right into the
internal fixed table, add helpers.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---

v2: fix test fallbacks for older releases

 src/include/liburing.h | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/src/include/liburing.h b/src/include/liburing.h
index 7b364ce..3b9cfb5 100644
--- a/src/include/liburing.h
+++ b/src/include/liburing.h
@@ -231,6 +231,13 @@ static inline void io_uring_sqe_set_flags(struct io_uring_sqe *sqe,
 	sqe->flags = flags;
 }
 
+static inline void __io_uring_set_target_fixed_file(struct io_uring_sqe *sqe,
+						    unsigned int file_index)
+{
+	/* 0 means no fixed files, indexes should be encoded as "index + 1" */
+	sqe->file_index = file_index + 1;
+}
+
 static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
 				    const void *addr, unsigned len,
 				    __u64 offset)
@@ -423,6 +430,16 @@ static inline void io_uring_prep_accept(struct io_uring_sqe *sqe, int fd,
 	sqe->accept_flags = flags;
 }
 
+/* accept directly into the fixed file table */
+static inline void io_uring_prep_accept_direct(struct io_uring_sqe *sqe, int fd,
+					       struct sockaddr *addr,
+					       socklen_t *addrlen, int flags,
+					       unsigned int file_index)
+{
+	io_uring_prep_accept(sqe, fd, addr, addrlen, flags);
+	__io_uring_set_target_fixed_file(sqe, file_index);
+}
+
 static inline void io_uring_prep_cancel(struct io_uring_sqe *sqe, void *user_data,
 					int flags)
 {
@@ -467,6 +484,17 @@ static inline void io_uring_prep_openat(struct io_uring_sqe *sqe, int dfd,
 	sqe->open_flags = flags;
 }
 
+/* open directly into the fixed file table */
+static inline void io_uring_prep_openat_direct(struct io_uring_sqe *sqe,
+					       int dfd, const char *path,
+					       int flags, mode_t mode,
+					       unsigned file_index)
+{
+	io_uring_prep_openat(sqe, dfd, path, flags, mode);
+	__io_uring_set_target_fixed_file(sqe, file_index);
+}
+
+
 static inline void io_uring_prep_close(struct io_uring_sqe *sqe, int fd)
 {
 	io_uring_prep_rw(IORING_OP_CLOSE, sqe, fd, NULL, 0, 0);
@@ -529,6 +557,16 @@ static inline void io_uring_prep_openat2(struct io_uring_sqe *sqe, int dfd,
 				(uint64_t) (uintptr_t) how);
 }
 
+/* open directly into the fixed file table */
+static inline void io_uring_prep_openat2_direct(struct io_uring_sqe *sqe,
+						int dfd, const char *path,
+						struct open_how *how,
+						unsigned file_index)
+{
+	io_uring_prep_openat2(sqe, dfd, path, how);
+	__io_uring_set_target_fixed_file(sqe, file_index);
+}
+
 struct epoll_event;
 static inline void io_uring_prep_epoll_ctl(struct io_uring_sqe *sqe, int epfd,
 					   int fd, int op,
-- 
2.33.0