/* SPDX-License-Identifier: GPL-2.0 */
#ifndef IOU_CORE_H
#define IOU_CORE_H

#include <linux/errno.h>
#include <linux/lockdep.h>
#include <linux/resume_user_mode.h>
#include <linux/poll.h>
#include <linux/io_uring_types.h>
#include <uapi/linux/eventpoll.h>
#include "alloc_cache.h"
#include "io-wq.h"
#include "slist.h"
#include "tw.h"
#include "opdef.h"

#ifndef CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
#endif

struct io_rings_layout {
        /* size of CQ + headers + SQ offset array */
        size_t rings_size;
        size_t sq_size;

        size_t sq_array_offset;
};

struct io_ctx_config {
        struct io_uring_params p;
        struct io_rings_layout layout;
        struct io_uring_params __user *uptr;
};

#define IORING_FEAT_FLAGS (IORING_FEAT_SINGLE_MMAP |\
                        IORING_FEAT_NODROP |\
                        IORING_FEAT_SUBMIT_STABLE |\
                        IORING_FEAT_RW_CUR_POS |\
                        IORING_FEAT_CUR_PERSONALITY |\
                        IORING_FEAT_FAST_POLL |\
                        IORING_FEAT_POLL_32BITS |\
                        IORING_FEAT_SQPOLL_NONFIXED |\
                        IORING_FEAT_EXT_ARG |\
                        IORING_FEAT_NATIVE_WORKERS |\
                        IORING_FEAT_RSRC_TAGS |\
                        IORING_FEAT_CQE_SKIP |\
                        IORING_FEAT_LINKED_FILE |\
                        IORING_FEAT_REG_REG_RING |\
                        IORING_FEAT_RECVSEND_BUNDLE |\
                        IORING_FEAT_MIN_TIMEOUT |\
                        IORING_FEAT_RW_ATTR |\
                        IORING_FEAT_NO_IOWAIT)

#define IORING_SETUP_FLAGS (IORING_SETUP_IOPOLL |\
                        IORING_SETUP_SQPOLL |\
                        IORING_SETUP_SQ_AFF |\
                        IORING_SETUP_CQSIZE |\
                        IORING_SETUP_CLAMP |\
                        IORING_SETUP_ATTACH_WQ |\
                        IORING_SETUP_R_DISABLED |\
                        IORING_SETUP_SUBMIT_ALL |\
                        IORING_SETUP_COOP_TASKRUN |\
                        IORING_SETUP_TASKRUN_FLAG |\
                        IORING_SETUP_SQE128 |\
                        IORING_SETUP_CQE32 |\
                        IORING_SETUP_SINGLE_ISSUER |\
                        IORING_SETUP_DEFER_TASKRUN |\
                        IORING_SETUP_NO_MMAP |\
                        IORING_SETUP_REGISTERED_FD_ONLY |\
                        IORING_SETUP_NO_SQARRAY |\
                        IORING_SETUP_HYBRID_IOPOLL |\
                        IORING_SETUP_CQE_MIXED |\
                        IORING_SETUP_SQE_MIXED |\
                        IORING_SETUP_SQ_REWIND)

#define IORING_ENTER_FLAGS (IORING_ENTER_GETEVENTS |\
                        IORING_ENTER_SQ_WAKEUP |\
                        IORING_ENTER_SQ_WAIT |\
                        IORING_ENTER_EXT_ARG |\
                        IORING_ENTER_REGISTERED_RING |\
                        IORING_ENTER_ABS_TIMER |\
                        IORING_ENTER_EXT_ARG_REG |\
                        IORING_ENTER_NO_IOWAIT)


#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE |\
                        IOSQE_IO_DRAIN |\
                        IOSQE_IO_LINK |\
                        IOSQE_IO_HARDLINK |\
                        IOSQE_ASYNC |\
                        IOSQE_BUFFER_SELECT |\
                        IOSQE_CQE_SKIP_SUCCESS)

#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)

/*
 * Complaint timeout for io_uring cancelation exits, and for io-wq exit
 * worker waiting.
 */
#define IO_URING_EXIT_WAIT_MAX  (HZ * 60 * 5)

enum {
        IOU_COMPLETE            = 0,

        IOU_ISSUE_SKIP_COMPLETE = -EIOCBQUEUED,

        /*
         * The request has more work to do and should be retried. io_uring will
         * attempt to wait on the file for eligible opcodes, but otherwise
         * it'll be handed to iowq for blocking execution. It works for normal
         * requests as well as for the multi shot mode.
         */
        IOU_RETRY               = -EAGAIN,

        /*
         * Requeue the task_work to restart operations on this request. The
         * actual value isn't important, should just be not an otherwise
         * valid error code, yet less than -MAX_ERRNO and valid internally.
         */
        IOU_REQUEUE             = -3072,
};

struct io_defer_entry {
        struct list_head        list;
        struct io_kiocb         *req;
};

struct io_wait_queue {
        struct wait_queue_entry wq;
        struct io_ring_ctx *ctx;
        unsigned cq_tail;
        unsigned cq_min_tail;
        unsigned nr_timeouts;
        int hit_timeout;
        ktime_t min_timeout;
        ktime_t timeout;
        struct hrtimer t;

#ifdef CONFIG_NET_RX_BUSY_POLL
        ktime_t napi_busy_poll_dt;
        bool napi_prefer_busy_poll;
#endif
};

static inline struct io_rings *io_get_rings(struct io_ring_ctx *ctx)
{
        return rcu_dereference_check(ctx->rings_rcu,
                        lockdep_is_held(&ctx->uring_lock) ||
                        lockdep_is_held(&ctx->completion_lock));
}

static inline bool io_should_wake(struct io_wait_queue *iowq)
{
        struct io_ring_ctx *ctx = iowq->ctx;
        struct io_rings *rings;
        int dist;

        guard(rcu)();
        rings = io_get_rings(ctx);

        /*
         * Wake up if we have enough events, or if a timeout occurred since we
         * started waiting. For timeouts, we always want to return to userspace,
         * regardless of event count.
         */
        dist = READ_ONCE(rings->cq.tail) - (int) iowq->cq_tail;
        return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
}

#define IORING_MAX_ENTRIES      32768
#define IORING_MAX_CQ_ENTRIES   (2 * IORING_MAX_ENTRIES)

int io_prepare_config(struct io_ctx_config *config);

bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow, bool cqe32);
void io_req_defer_failed(struct io_kiocb *req, s32 res);
bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
void io_add_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
bool io_req_post_cqe(struct io_kiocb *req, s32 res, u32 cflags);
bool io_req_post_cqe32(struct io_kiocb *req, struct io_uring_cqe src_cqe[2]);
void __io_commit_cqring_flush(struct io_ring_ctx *ctx);

unsigned io_linked_nr(struct io_kiocb *req);
void io_req_track_inflight(struct io_kiocb *req);
struct file *io_file_get_normal(struct io_kiocb *req, int fd);
struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
                               unsigned issue_flags);

void io_req_task_queue(struct io_kiocb *req);
void io_req_task_complete(struct io_tw_req tw_req, io_tw_token_t tw);
void io_req_task_queue_fail(struct io_kiocb *req, int ret);
void io_req_task_submit(struct io_tw_req tw_req, io_tw_token_t tw);
__cold void io_uring_drop_tctx_refs(struct task_struct *task);

int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
                                     int start, int end);
void io_req_queue_iowq(struct io_kiocb *req);

int io_poll_issue(struct io_kiocb *req, io_tw_token_t tw);
int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
__cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx);
void __io_submit_flush_completions(struct io_ring_ctx *ctx);

struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
void io_wq_submit_work(struct io_wq_work *work);

void io_free_req(struct io_kiocb *req);
void io_queue_next(struct io_kiocb *req);
void io_task_refs_refill(struct io_uring_task *tctx);
bool __io_alloc_req_refill(struct io_ring_ctx *ctx);

void io_activate_pollwq(struct io_ring_ctx *ctx);
void io_restriction_clone(struct io_restriction *dst, struct io_restriction *src);

static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
{
#if defined(CONFIG_PROVE_LOCKING)
        lockdep_assert(in_task());

        if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
                lockdep_assert_held(&ctx->uring_lock);

        if (ctx->flags & IORING_SETUP_IOPOLL) {
                lockdep_assert_held(&ctx->uring_lock);
        } else if (!ctx->task_complete) {
                lockdep_assert_held(&ctx->completion_lock);
        } else if (ctx->submitter_task) {
                /*
                 * ->submitter_task may be NULL and we can still post a CQE,
                 * if the ring has been setup with IORING_SETUP_R_DISABLED.
                 * Not from an SQE, as those cannot be submitted, but via
                 * updating tagged resources.
                 */
                if (!percpu_ref_is_dying(&ctx->refs))
                        lockdep_assert(current == ctx->submitter_task);
        }
#endif
}

static inline bool io_is_compat(struct io_ring_ctx *ctx)
{
        return IS_ENABLED(CONFIG_COMPAT) && unlikely(ctx->compat);
}

static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
{
        if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
            ctx->submit_state.cq_flush)
                __io_submit_flush_completions(ctx);
}

#define io_for_each_link(pos, head) \
        for (pos = (head); pos; pos = pos->link)

static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
                                        struct io_uring_cqe **ret,
                                        bool overflow, bool cqe32)
{
        io_lockdep_assert_cq_locked(ctx);

        if (unlikely(ctx->cqe_sentinel - ctx->cqe_cached < (cqe32 + 1))) {
                if (unlikely(!io_cqe_cache_refill(ctx, overflow, cqe32)))
                        return false;
        }
        *ret = ctx->cqe_cached;
        ctx->cached_cq_tail++;
        ctx->cqe_cached++;
        if (ctx->flags & IORING_SETUP_CQE32) {
                ctx->cqe_cached++;
        } else if (cqe32 && ctx->flags & IORING_SETUP_CQE_MIXED) {
                ctx->cqe_cached++;
                ctx->cached_cq_tail++;
        }
        WARN_ON_ONCE(ctx->cqe_cached > ctx->cqe_sentinel);
        return true;
}

static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret,
                                bool cqe32)
{
        return io_get_cqe_overflow(ctx, ret, false, cqe32);
}

static inline bool io_defer_get_uncommited_cqe(struct io_ring_ctx *ctx,
                                               struct io_uring_cqe **cqe_ret)
{
        io_lockdep_assert_cq_locked(ctx);

        ctx->submit_state.cq_flush = true;
        return io_get_cqe(ctx, cqe_ret, ctx->flags & IORING_SETUP_CQE_MIXED);
}

static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
                                            struct io_kiocb *req)
{
        bool is_cqe32 = req->cqe.flags & IORING_CQE_F_32;
        struct io_uring_cqe *cqe;

        /*
         * If we can't get a cq entry, userspace overflowed the submission
         * (by quite a lot).
         */
        if (unlikely(!io_get_cqe(ctx, &cqe, is_cqe32)))
                return false;

        memcpy(cqe, &req->cqe, sizeof(*cqe));
        if (ctx->flags & IORING_SETUP_CQE32 || is_cqe32) {
                memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
                memset(&req->big_cqe, 0, sizeof(req->big_cqe));
        }

        if (trace_io_uring_complete_enabled())
                trace_io_uring_complete(req->ctx, req, cqe);
        return true;
}

static inline void req_set_fail(struct io_kiocb *req)
{
        req->flags |= REQ_F_FAIL;
        if (req->flags & REQ_F_CQE_SKIP) {
                req->flags &= ~REQ_F_CQE_SKIP;
                req->flags |= REQ_F_SKIP_LINK_CQES;
        }
}

static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
{
        req->cqe.res = res;
        req->cqe.flags = cflags;
}

static inline u32 ctx_cqe32_flags(struct io_ring_ctx *ctx)
{
        if (ctx->flags & IORING_SETUP_CQE_MIXED)
                return IORING_CQE_F_32;
        return 0;
}

static inline void io_req_set_res32(struct io_kiocb *req, s32 res, u32 cflags,
                                    __u64 extra1, __u64 extra2)
{
        req->cqe.res = res;
        req->cqe.flags = cflags | ctx_cqe32_flags(req->ctx);
        req->big_cqe.extra1 = extra1;
        req->big_cqe.extra2 = extra2;
}

static inline void *io_uring_alloc_async_data(struct io_alloc_cache *cache,
                                              struct io_kiocb *req)
{
        if (cache) {
                req->async_data = io_cache_alloc(cache, GFP_KERNEL);
        } else {
                const struct io_issue_def *def = &io_issue_defs[req->opcode];

                WARN_ON_ONCE(!def->async_size);
                req->async_data = kmalloc(def->async_size, GFP_KERNEL);
        }
        if (req->async_data)
                req->flags |= REQ_F_ASYNC_DATA;
        return req->async_data;
}

static inline bool req_has_async_data(struct io_kiocb *req)
{
        return req->flags & REQ_F_ASYNC_DATA;
}

static inline void io_req_async_data_clear(struct io_kiocb *req,
                                           io_req_flags_t extra_flags)
{
        req->flags &= ~(REQ_F_ASYNC_DATA|extra_flags);
        req->async_data = NULL;
}

static inline void io_req_async_data_free(struct io_kiocb *req)
{
        kfree(req->async_data);
        io_req_async_data_clear(req, 0);
}

static inline void io_put_file(struct io_kiocb *req)
{
        if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
                fput(req->file);
}

static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
                                         unsigned issue_flags)
{
        lockdep_assert_held(&ctx->uring_lock);
        if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
                mutex_unlock(&ctx->uring_lock);
}

static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
                                       unsigned issue_flags)
{
        /*
         * "Normal" inline submissions always hold the uring_lock, since we
         * grab it from the system call. Same is true for the SQPOLL offload.
         * The only exception is when we've detached the request and issue it
         * from an async worker thread, grab the lock for that case.
         */
        if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
                mutex_lock(&ctx->uring_lock);
        lockdep_assert_held(&ctx->uring_lock);
}

static inline void io_commit_cqring(struct io_ring_ctx *ctx)
{
        /* order cqe stores with ring update */
        smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
}

static inline void __io_wq_wake(struct wait_queue_head *wq)
{
        /*
         *
         * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
         * set in the mask so that if we recurse back into our own poll
         * waitqueue handlers, we know we have a dependency between eventfd or
         * epoll and should terminate multishot poll at that point.
         */
        if (wq_has_sleeper(wq))
                __wake_up(wq, TASK_NORMAL, 0, poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
}

static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
{
        __io_wq_wake(&ctx->poll_wq);
}

static inline void io_cqring_wake(struct io_ring_ctx *ctx)
{
        /*
         * Trigger waitqueue handler on all waiters on our waitqueue. This
         * won't necessarily wake up all the tasks, io_should_wake() will make
         * that decision.
         */

        __io_wq_wake(&ctx->cq_wait);
}

static inline bool __io_sqring_full(struct io_ring_ctx *ctx)
{
        struct io_rings *r = io_get_rings(ctx);

        /*
         * SQPOLL must use the actual sqring head, as using the cached_sq_head
         * is race prone if the SQPOLL thread has grabbed entries but not yet
         * committed them to the ring. For !SQPOLL, this doesn't matter, but
         * since this helper is just used for SQPOLL sqring waits (or POLLOUT),
         * just read the actual sqring head unconditionally.
         */
        return READ_ONCE(r->sq.tail) - READ_ONCE(r->sq.head) == ctx->sq_entries;
}

static inline bool io_sqring_full(struct io_ring_ctx *ctx)
{
        guard(rcu)();
        return __io_sqring_full(ctx);
}

static inline unsigned int __io_sqring_entries(struct io_ring_ctx *ctx)
{
        struct io_rings *rings = io_get_rings(ctx);
        unsigned int entries;

        /* make sure SQ entry isn't read before tail */
        entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
        return min(entries, ctx->sq_entries);
}

static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
{
        guard(rcu)();
        return __io_sqring_entries(ctx);
}

/*
 * Don't complete immediately but use deferred completion infrastructure.
 * Protected by ->uring_lock and can only be used either with
 * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
 */
static inline void io_req_complete_defer(struct io_kiocb *req)
        __must_hold(&req->ctx->uring_lock)
{
        struct io_submit_state *state = &req->ctx->submit_state;

        lockdep_assert_held(&req->ctx->uring_lock);

        wq_list_add_tail(&req->comp_list, &state->compl_reqs);
}

static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
{
        if (unlikely(ctx->off_timeout_used ||
                     ctx->has_evfd || ctx->poll_activated))
                __io_commit_cqring_flush(ctx);
}

static inline void io_get_task_refs(int nr)
{
        struct io_uring_task *tctx = current->io_uring;

        tctx->cached_refs -= nr;
        if (unlikely(tctx->cached_refs < 0))
                io_task_refs_refill(tctx);
}

static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
{
        return !ctx->submit_state.free_list.next;
}

extern struct kmem_cache *req_cachep;

static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
{
        struct io_kiocb *req;

        req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
        wq_stack_extract(&ctx->submit_state.free_list);
        return req;
}

static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
{
        if (unlikely(io_req_cache_empty(ctx))) {
                if (!__io_alloc_req_refill(ctx))
                        return false;
        }
        *req = io_extract_req(ctx);
        return true;
}

static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
{
        io_req_set_res(req, res, 0);
        req->io_task_work.func = io_req_task_complete;
        io_req_task_work_add(req);
}

static inline bool io_file_can_poll(struct io_kiocb *req)
{
        if (req->flags & REQ_F_CAN_POLL)
                return true;
        if (req->file && file_can_poll(req->file)) {
                req->flags |= REQ_F_CAN_POLL;
                return true;
        }
        return false;
}

static inline bool io_is_uring_cmd(const struct io_kiocb *req)
{
        return req->opcode == IORING_OP_URING_CMD ||
               req->opcode == IORING_OP_URING_CMD128;
}

static inline ktime_t io_get_time(struct io_ring_ctx *ctx)
{
        if (ctx->clockid == CLOCK_MONOTONIC)
                return ktime_get();

        return ktime_get_with_offset(ctx->clock_offset);
}

enum {
        IO_CHECK_CQ_OVERFLOW_BIT,
        IO_CHECK_CQ_DROPPED_BIT,
};

static inline bool io_has_work(struct io_ring_ctx *ctx)
{
        return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
               io_local_work_pending(ctx);
}
#endif