src/Makefile: keep private headers in <liburing/*.h>

It is not possible to install barrier.h and compat.h into the top-level
/usr/include directly since they are likely to conflict with other
software.  io_uring.h could be confused with the system's kernel header
file.

Put liburing headers into <liburing/*.h> so there is no chance of
conflicts or confusion.

Existing applications continue to build successfully since the location
of <liburing.h> is unchanged.  In-tree examples and tests require
modification because src/liburing.h is moved to src/include/liburing.h.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 241 insertions, 0 deletions

diff --git a/src/include/liburing/barrier.h b/src/include/liburing/barrier.h
new file mode 100644
index 0000000..98be9e5
--- /dev/null
+++ b/src/include/liburing/barrier.h
@@ -0,0 +1,87 @@
+#ifndef LIBURING_BARRIER_H
+#define LIBURING_BARRIER_H
+
+/*
+From the kernel documentation file refcount-vs-atomic.rst:
+
+A RELEASE memory ordering guarantees that all prior loads and
+stores (all po-earlier instructions) on the same CPU are completed
+before the operation. It also guarantees that all po-earlier
+stores on the same CPU and all propagated stores from other CPUs
+must propagate to all other CPUs before the release operation
+(A-cumulative property). This is implemented using
+:c:func:`smp_store_release`.
+
+An ACQUIRE memory ordering guarantees that all post loads and
+stores (all po-later instructions) on the same CPU are
+completed after the acquire operation. It also guarantees that all
+po-later stores on the same CPU must propagate to all other CPUs
+after the acquire operation executes. This is implemented using
+:c:func:`smp_acquire__after_ctrl_dep`.
+*/
+
+/* From tools/include/linux/compiler.h */
+/* Optimization barrier */
+/* The "volatile" is due to gcc bugs */
+#define barrier() __asm__ __volatile__("": : :"memory")
+
+/* From tools/virtio/linux/compiler.h */
+#define WRITE_ONCE(var, val) \
+	(*((volatile __typeof(val) *)(&(var))) = (val))
+#define READ_ONCE(var) (*((volatile __typeof(var) *)(&(var))))
+
+
+#if defined(__x86_64__) || defined(__i386__)
+/* Adapted from arch/x86/include/asm/barrier.h */
+#define mb()	asm volatile("mfence" ::: "memory")
+#define rmb()	asm volatile("lfence" ::: "memory")
+#define wmb()	asm volatile("sfence" ::: "memory")
+#define smp_rmb() barrier()
+#define smp_wmb() barrier()
+#if defined(__i386__)
+#define smp_mb()  asm volatile("lock; addl $0,0(%%esp)" ::: "memory", "cc")
+#else
+#define smp_mb()  asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc")
+#endif
+
+#define smp_store_release(p, v)			\
+do {						\
+	barrier();				\
+	WRITE_ONCE(*(p), (v));			\
+} while (0)
+
+#define smp_load_acquire(p)			\
+({						\
+	__typeof(*p) ___p1 = READ_ONCE(*(p));	\
+	barrier();				\
+	___p1;					\
+})
+#else /* defined(__x86_64__) || defined(__i386__) */
+/*
+ * Add arch appropriate definitions. Be safe and use full barriers for
+ * archs we don't have support for.
+ */
+#define smp_rmb()	__sync_synchronize()
+#define smp_wmb()	__sync_synchronize()
+#endif /* defined(__x86_64__) || defined(__i386__) */
+
+/* From tools/include/asm/barrier.h */
+
+#ifndef smp_store_release
+# define smp_store_release(p, v)		\
+do {						\
+	smp_mb();				\
+	WRITE_ONCE(*p, v);			\
+} while (0)
+#endif
+
+#ifndef smp_load_acquire
+# define smp_load_acquire(p)			\
+({						\
+	__typeof(*p) ___p1 = READ_ONCE(*p);	\
+	smp_mb();				\
+	___p1;					\
+})
+#endif
+
+#endif /* defined(LIBURING_BARRIER_H) */
diff --git a/src/include/liburing/compat.h b/src/include/liburing/compat.h
new file mode 100644
index 0000000..d322499
--- /dev/null
+++ b/src/include/liburing/compat.h
@@ -0,0 +1,8 @@
+#ifndef LIBURING_COMPAT_H
+#define LIBURING_COMPAT_H
+
+#if !defined(CONFIG_HAVE_KERNEL_RWF_T)
+typedef int __kernel_rwf_t;
+#endif
+
+#endif
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
new file mode 100644
index 0000000..a61c4a6
--- /dev/null
+++ b/src/include/liburing/io_uring.h
@@ -0,0 +1,146 @@
+/* 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 (Submission Queue Entry)
+ */
+struct io_uring_sqe {
+	__u8	opcode;		/* type of operation for this sqe */
+	__u8	flags;		/* IOSQE_ flags */
+	__u16	ioprio;		/* ioprio for the request */
+	__s32	fd;		/* file descriptor to do IO on */
+	__u64	off;		/* offset into file */
+	__u64	addr;		/* pointer to buffer or iovecs */
+	__u32	len;		/* buffer size or number of iovecs */
+	union {
+		__kernel_rwf_t	rw_flags;
+		__u32		fsync_flags;
+		__u16		poll_events;
+		__u32		sync_range_flags;
+		__u32		msg_flags;
+	};
+	__u64	user_data;	/* data to be passed back at completion time */
+	union {
+		__u16	buf_index;	/* index into fixed buffers, if used */
+		__u64	__pad2[3];
+	};
+};
+
+/*
+ * sqe->flags
+ */
+#define IOSQE_FIXED_FILE	(1U << 0)	/* use fixed fileset */
+#define IOSQE_IO_DRAIN		(1U << 1)	/* issue after inflight IO */
+#define IOSQE_IO_LINK		(1U << 2)	/* next IO depends on this one */
+
+/*
+ * io_uring_setup() flags
+ */
+#define IORING_SETUP_IOPOLL	(1U << 0)	/* io_context is polled */
+#define IORING_SETUP_SQPOLL	(1U << 1)	/* SQ poll thread */
+#define IORING_SETUP_SQ_AFF	(1U << 2)	/* sq_thread_cpu is valid */
+
+#define IORING_OP_NOP		0
+#define IORING_OP_READV		1
+#define IORING_OP_WRITEV	2
+#define IORING_OP_FSYNC		3
+#define IORING_OP_READ_FIXED	4
+#define IORING_OP_WRITE_FIXED	5
+#define IORING_OP_POLL_ADD	6
+#define IORING_OP_POLL_REMOVE	7
+#define IORING_OP_SYNC_FILE_RANGE	8
+#define IORING_OP_SENDMSG	9
+#define IORING_OP_RECVMSG	10
+
+/*
+ * sqe->fsync_flags
+ */
+#define IORING_FSYNC_DATASYNC	(1U << 0)
+
+/*
+ * IO completion data structure (Completion Queue Entry)
+ */
+struct io_uring_cqe {
+	__u64	user_data;	/* sqe->data submission passed back */
+	__s32	res;		/* result code for this event */
+	__u32	flags;
+};
+
+/*
+ * 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_SQES			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 resv1;
+	__u64 resv2;
+};
+
+/*
+ * sq_ring->flags
+ */
+#define IORING_SQ_NEED_WAKEUP	(1U << 0) /* needs io_uring_enter wakeup */
+
+struct io_cqring_offsets {
+	__u32 head;
+	__u32 tail;
+	__u32 ring_mask;
+	__u32 ring_entries;
+	__u32 overflow;
+	__u32 cqes;
+	__u64 resv[2];
+};
+
+/*
+ * io_uring_enter(2) flags
+ */
+#define IORING_ENTER_GETEVENTS	(1U << 0)
+#define IORING_ENTER_SQ_WAKEUP	(1U << 1)
+
+/*
+ * 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;
+	__u32 sq_thread_cpu;
+	__u32 sq_thread_idle;
+	__u32 resv[5];
+	struct io_sqring_offsets sq_off;
+	struct io_cqring_offsets cq_off;
+};
+
+/*
+ * io_uring_register(2) opcodes and arguments
+ */
+#define IORING_REGISTER_BUFFERS		0
+#define IORING_UNREGISTER_BUFFERS	1
+#define IORING_REGISTER_FILES		2
+#define IORING_UNREGISTER_FILES		3
+#define IORING_REGISTER_EVENTFD		4
+#define IORING_UNREGISTER_EVENTFD	5
+
+#endif