source: libcfa/src/concurrency/io/types.hfa@ c402739f

//
// Cforall Version 1.0.0 Copyright (C) 2020 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// io/types.hfa --
//
// Author           : Thierry Delisle
// Created On       : Fri Jul 31 16:22:47 2020
// Last Modified By :
// Last Modified On :
// Update Count     :
//

#pragma once

#if defined(CFA_HAVE_LINUX_IO_URING_H)
        extern "C" {
                #include <linux/types.h>
        }

      #include "bits/locks.hfa"

        #define LEADER_LOCK
        struct __leaderlock_t {
                struct $thread * volatile value;        // ($thread) next_leader | (bool:1) is_locked
        };

        static inline void ?{}( __leaderlock_t & this ) { this.value = 0p; }

        //-----------------------------------------------------------------------
        // Ring Data structure
      struct __submition_data {
                // Head and tail of the ring (associated with array)
                volatile __u32 * head;
                volatile __u32 * tail;
                volatile __u32 prev_head;

                // The actual kernel ring which uses head/tail
                // indexes into the sqes arrays
                __u32 * array;

                // number of entries and mask to go with it
                const __u32 * num;
                const __u32 * mask;

                // Submission flags (Not sure what for)
                __u32 * flags;

                // number of sqes not submitted (whatever that means)
                __u32 * dropped;

                // Like head/tail but not seen by the kernel
                volatile __u32 * ready;
                __u32 ready_cnt;
                __u32 prev_ready;

                #if defined(LEADER_LOCK)
                        __leaderlock_t submit_lock;
                #else
                        __spinlock_t submit_lock;
                #endif
                __spinlock_t  release_lock;

                // A buffer of sqes (not the actual ring)
                struct io_uring_sqe * sqes;

                // The location and size of the mmaped area
                void * ring_ptr;
                size_t ring_sz;
        };

        struct __completion_data {
                // Head and tail of the ring
                volatile __u32 * head;
                volatile __u32 * tail;

                // number of entries and mask to go with it
                const __u32 * mask;
                const __u32 * num;

                // number of cqes not submitted (whatever that means)
                __u32 * overflow;

                // the kernel ring
                struct io_uring_cqe * cqes;

                // The location and size of the mmaped area
                void * ring_ptr;
                size_t ring_sz;
        };

        struct __io_data {
                struct __submition_data submit_q;
                struct __completion_data completion_q;
                __u32 ring_flags;
                int fd;
                bool eager_submits:1;
                bool poller_submits:1;
        };


        //-----------------------------------------------------------------------
        // IO user data
        struct io_future_t {
                future_t self;
                __s32 result;
        };

        static inline {
                bool fulfil( io_future_t & this, __s32 result ) {
                        this.result = result;
                        return fulfil(this.self);
                }

                // Wait for the future to be fulfilled
                bool wait( io_future_t & this ) {
                        return wait(this.self);
                }
        }

        //-----------------------------------------------------------------------
        // Misc
        // Weirdly, some systems that do support io_uring don't actually define these
        #ifdef __alpha__
                /*
                * alpha is the only exception, all other architectures
                * have common numbers for new system calls.
                */
                #ifndef __NR_io_uring_setup
                        #define __NR_io_uring_setup           535
                #endif
                #ifndef __NR_io_uring_enter
                        #define __NR_io_uring_enter           536
                #endif
                #ifndef __NR_io_uring_register
                        #define __NR_io_uring_register        537
                #endif
        #else /* !__alpha__ */
                #ifndef __NR_io_uring_setup
                        #define __NR_io_uring_setup           425
                #endif
                #ifndef __NR_io_uring_enter
                        #define __NR_io_uring_enter           426
                #endif
                #ifndef __NR_io_uring_register
                        #define __NR_io_uring_register        427
                #endif
        #endif

        struct epoll_event;
        struct $io_ctx_thread;
        void __ioctx_register($io_ctx_thread & ctx, struct epoll_event & ev);
        void __ioctx_prepare_block($io_ctx_thread & ctx, struct epoll_event & ev);
#endif