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+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Header file for the io_uring interface.
+ *
+ * Copyright (C) 2019 Jens Axboe
+ * Copyright (C) 2019 Christoph Hellwig
+ */
+#ifndef LINUX_IO_URING_H
+#define LINUX_IO_URING_H
+
+#include <linux/fs.h>
+#include <linux/types.h>
+
+/*
+ * IO submission data structure
+ */
+struct io_uring_iocb {
+ __u8 opcode;
+ __u8 flags;
+ __u16 ioprio;
+ __s32 fd;
+ __u64 off;
+ union {
+ void *addr;
+ __u64 __pad;
+ };
+ __u32 len;
+ union {
+ __kernel_rwf_t rw_flags;
+ __u32 __resv;
+ };
+};
+
+/*
+ * io_uring_setup() flags
+ */
+#define IORING_SETUP_IOPOLL (1 << 0) /* io_context is polled */
+#define IORING_SETUP_FIXEDBUFS (1 << 1) /* IO buffers are fixed */
+#define IORING_SETUP_SQTHREAD (1 << 2) /* Use SQ thread */
+#define IORING_SETUP_SQWQ (1 << 3) /* Use SQ workqueue */
+#define IORING_SETUP_SQPOLL (1 << 4) /* SQ thread polls */
+
+#define IORING_OP_READ 1
+#define IORING_OP_WRITE 2
+#define IORING_OP_FSYNC 3
+#define IORING_OP_FDSYNC 4
+#define IORING_OP_READ_FIXED 5
+#define IORING_OP_WRITE_FIXED 6
+
+/*
+ * IO completion data structure
+ */
+struct io_uring_event {
+ __u64 index; /* what iocb this event came from */
+ __s32 res; /* result code for this event */
+ __u32 flags;
+};
+
+/*
+ * io_uring_event->flags
+ */
+#define IOEV_FLAG_CACHEHIT (1 << 0) /* IO did not hit media */
+
+/*
+ * Magic offsets for the application to mmap the data it needs
+ */
+#define IORING_OFF_SQ_RING 0ULL
+#define IORING_OFF_CQ_RING 0x8000000ULL
+#define IORING_OFF_IOCB 0x10000000ULL
+
+/*
+ * Filled with the offset for mmap(2)
+ */
+struct io_sqring_offsets {
+ __u32 head;
+ __u32 tail;
+ __u32 ring_mask;
+ __u32 ring_entries;
+ __u32 flags;
+ __u32 dropped;
+ __u32 array;
+ __u32 resv[3];
+};
+
+#define IORING_SQ_NEED_WAKEUP (1 << 0) /* needs io_uring_enter wakeup */
+
+struct io_cqring_offsets {
+ __u32 head;
+ __u32 tail;
+ __u32 ring_mask;
+ __u32 ring_entries;
+ __u32 overflow;
+ __u32 events;
+ __u32 resv[4];
+};
+
+/*
+ * io_uring_enter(2) flags
+ */
+#define IORING_ENTER_GETEVENTS (1 << 0)
+
+/*
+ * Passed in for io_uring_setup(2). Copied back with updated info on success
+ */
+struct io_uring_params {
+ __u32 sq_entries;
+ __u32 cq_entries;
+ __u32 flags;
+ __u16 sq_thread_cpu;
+ __u16 resv[9];
+ struct io_sqring_offsets sq_off;
+ struct io_cqring_offsets cq_off;
+};
+
+#endif