// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/nospec.h>
#include <linux/io_uring.h>

#include <uapi/linux/io_uring.h>

#include "filetable.h"
#include "sqpoll.h"
#include "fdinfo.h"
#include "cancel.h"
#include "rsrc.h"
#include "opdef.h"

#ifdef CONFIG_NET_RX_BUSY_POLL
static __cold void common_tracking_show_fdinfo(struct io_ring_ctx *ctx,
                                               struct seq_file *m,
                                               const char *tracking_strategy)
{
        seq_puts(m, "NAPI:\tenabled\n");
        seq_printf(m, "napi tracking:\t%s\n", tracking_strategy);
        seq_printf(m, "napi_busy_poll_dt:\t%llu\n", ctx->napi_busy_poll_dt);
        if (ctx->napi_prefer_busy_poll)
                seq_puts(m, "napi_prefer_busy_poll:\ttrue\n");
        else
                seq_puts(m, "napi_prefer_busy_poll:\tfalse\n");
}

static __cold void napi_show_fdinfo(struct io_ring_ctx *ctx,
                                    struct seq_file *m)
{
        unsigned int mode = READ_ONCE(ctx->napi_track_mode);

        switch (mode) {
        case IO_URING_NAPI_TRACKING_INACTIVE:
                seq_puts(m, "NAPI:\tdisabled\n");
                break;
        case IO_URING_NAPI_TRACKING_DYNAMIC:
                common_tracking_show_fdinfo(ctx, m, "dynamic");
                break;
        case IO_URING_NAPI_TRACKING_STATIC:
                common_tracking_show_fdinfo(ctx, m, "static");
                break;
        default:
                seq_printf(m, "NAPI:\tunknown mode (%u)\n", mode);
        }
}
#else
static inline void napi_show_fdinfo(struct io_ring_ctx *ctx,
                                    struct seq_file *m)
{
}
#endif

static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
{
        struct io_overflow_cqe *ocqe;
        struct io_rings *r = ctx->rings;
        unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1;
        unsigned int sq_head = READ_ONCE(r->sq.head);
        unsigned int sq_tail = READ_ONCE(r->sq.tail);
        unsigned int cq_head = READ_ONCE(r->cq.head);
        unsigned int cq_tail = READ_ONCE(r->cq.tail);
        unsigned int sq_shift = 0;
        unsigned int cq_entries, sq_entries;
        int sq_pid = -1, sq_cpu = -1;
        u64 sq_total_time = 0, sq_work_time = 0;
        unsigned int i;

        if (ctx->flags & IORING_SETUP_SQE128)
                sq_shift = 1;

        /*
         * we may get imprecise sqe and cqe info if uring is actively running
         * since we get cached_sq_head and cached_cq_tail without uring_lock
         * and sq_tail and cq_head are changed by userspace. But it's ok since
         * we usually use these info when it is stuck.
         */
        seq_printf(m, "SqMask:\t0x%x\n", sq_mask);
        seq_printf(m, "SqHead:\t%u\n", sq_head);
        seq_printf(m, "SqTail:\t%u\n", sq_tail);
        seq_printf(m, "CachedSqHead:\t%u\n", data_race(ctx->cached_sq_head));
        seq_printf(m, "CqMask:\t0x%x\n", cq_mask);
        seq_printf(m, "CqHead:\t%u\n", cq_head);
        seq_printf(m, "CqTail:\t%u\n", cq_tail);
        seq_printf(m, "CachedCqTail:\t%u\n", data_race(ctx->cached_cq_tail));
        seq_printf(m, "SQEs:\t%u\n", sq_tail - sq_head);
        sq_entries = min(sq_tail - sq_head, ctx->sq_entries);
        for (i = 0; i < sq_entries; i++) {
                unsigned int entry = i + sq_head;
                struct io_uring_sqe *sqe;
                unsigned int sq_idx;
                bool sqe128 = false;
                u8 opcode;

                if (ctx->flags & IORING_SETUP_NO_SQARRAY)
                        sq_idx = entry & sq_mask;
                else
                        sq_idx = READ_ONCE(ctx->sq_array[entry & sq_mask]);
                if (sq_idx > sq_mask)
                        continue;

                sqe = &ctx->sq_sqes[sq_idx << sq_shift];
                opcode = READ_ONCE(sqe->opcode);
                if (opcode >= IORING_OP_LAST)
                        continue;
                opcode = array_index_nospec(opcode, IORING_OP_LAST);
                if (sq_shift) {
                        sqe128 = true;
                } else if (io_issue_defs[opcode].is_128) {
                        if (!(ctx->flags & IORING_SETUP_SQE_MIXED)) {
                                seq_printf(m,
                                        "%5u: invalid sqe, 128B entry on non-mixed sq\n",
                                        sq_idx);
                                break;
                        }
                        if (sq_idx == sq_mask) {
                                seq_printf(m,
                                        "%5u: corrupted sqe, wrapping 128B entry\n",
                                        sq_idx);
                                break;
                        }
                        sq_head++;
                        i++;
                        sqe128 = true;
                }
                seq_printf(m, "%5u: opcode:%s, fd:%d, flags:%x, off:%llu, "
                              "addr:0x%llx, rw_flags:0x%x, buf_index:%d "
                              "user_data:%llu",
                           sq_idx, io_uring_get_opcode(opcode), sqe->fd,
                           sqe->flags, (unsigned long long) sqe->off,
                           (unsigned long long) sqe->addr, sqe->rw_flags,
                           sqe->buf_index, sqe->user_data);
                if (sqe128) {
                        u64 *sqeb = (void *) (sqe + 1);
                        int size = sizeof(struct io_uring_sqe) / sizeof(u64);
                        int j;

                        for (j = 0; j < size; j++) {
                                seq_printf(m, ", e%d:0x%llx", j,
                                                (unsigned long long) *sqeb);
                                sqeb++;
                        }
                }
                seq_printf(m, "\n");
                cond_resched();
        }
        seq_printf(m, "CQEs:\t%u\n", cq_tail - cq_head);
        cq_entries = min(cq_tail - cq_head, ctx->cq_entries);
        for (i = 0; i < cq_entries; i++) {
                struct io_uring_cqe *cqe;
                bool cqe32 = false;

                cqe = &r->cqes[(cq_head & cq_mask)];
                if (cqe->flags & IORING_CQE_F_32 || ctx->flags & IORING_SETUP_CQE32)
                        cqe32 = true;
                seq_printf(m, "%5u: user_data:%llu, res:%d, flags:%x",
                           cq_head & cq_mask, cqe->user_data, cqe->res,
                           cqe->flags);
                if (cqe32)
                        seq_printf(m, ", extra1:%llu, extra2:%llu",
                                        cqe->big_cqe[0], cqe->big_cqe[1]);
                seq_printf(m, "\n");
                cq_head++;
                if (cqe32) {
                        cq_head++;
                        i++;
                }
                cond_resched();
        }

        if (ctx->flags & IORING_SETUP_SQPOLL) {
                struct io_sq_data *sq = ctx->sq_data;
                struct task_struct *tsk;

                rcu_read_lock();
                tsk = rcu_dereference(sq->thread);
                /*
                 * sq->thread might be NULL if we raced with the sqpoll
                 * thread termination.
                 */
                if (tsk) {
                        u64 usec;

                        get_task_struct(tsk);
                        rcu_read_unlock();
                        usec = io_sq_cpu_usec(tsk);
                        put_task_struct(tsk);
                        sq_pid = sq->task_pid;
                        sq_cpu = sq->sq_cpu;
                        sq_total_time = usec;
                        sq_work_time = sq->work_time;
                } else {
                        rcu_read_unlock();
                }
        }

        seq_printf(m, "SqThread:\t%d\n", sq_pid);
        seq_printf(m, "SqThreadCpu:\t%d\n", sq_cpu);
        seq_printf(m, "SqTotalTime:\t%llu\n", sq_total_time);
        seq_printf(m, "SqWorkTime:\t%llu\n", sq_work_time);
        seq_printf(m, "UserFiles:\t%u\n", ctx->file_table.data.nr);
        for (i = 0; i < ctx->file_table.data.nr; i++) {
                struct file *f = NULL;

                if (ctx->file_table.data.nodes[i])
                        f = io_slot_file(ctx->file_table.data.nodes[i]);
                if (f) {
                        seq_printf(m, "%5u: ", i);
                        seq_file_path(m, f, " \t\n\\");
                        seq_puts(m, "\n");
                }
        }
        seq_printf(m, "UserBufs:\t%u\n", ctx->buf_table.nr);
        for (i = 0; i < ctx->buf_table.nr; i++) {
                struct io_mapped_ubuf *buf = NULL;

                if (ctx->buf_table.nodes[i])
                        buf = ctx->buf_table.nodes[i]->buf;
                if (buf)
                        seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, buf->len);
                else
                        seq_printf(m, "%5u: <none>\n", i);
        }

        seq_puts(m, "PollList:\n");
        for (i = 0; i < (1U << ctx->cancel_table.hash_bits); i++) {
                struct io_hash_bucket *hb = &ctx->cancel_table.hbs[i];
                struct io_kiocb *req;

                hlist_for_each_entry(req, &hb->list, hash_node)
                        seq_printf(m, "  op=%d, task_works=%d\n", req->opcode,
                                        task_work_pending(req->tctx->task));
        }

        seq_puts(m, "CqOverflowList:\n");
        spin_lock(&ctx->completion_lock);
        list_for_each_entry(ocqe, &ctx->cq_overflow_list, list) {
                struct io_uring_cqe *cqe = &ocqe->cqe;

                seq_printf(m, "  user_data=%llu, res=%d, flags=%x\n",
                           cqe->user_data, cqe->res, cqe->flags);

        }
        spin_unlock(&ctx->completion_lock);
        napi_show_fdinfo(ctx, m);
}

/*
 * Caller holds a reference to the file already, we don't need to do
 * anything else to get an extra reference.
 */
__cold void io_uring_show_fdinfo(struct seq_file *m, struct file *file)
{
        struct io_ring_ctx *ctx = file->private_data;

        /*
         * Avoid ABBA deadlock between the seq lock and the io_uring mutex,
         * since fdinfo case grabs it in the opposite direction of normal use
         * cases.
         */
        if (mutex_trylock(&ctx->uring_lock)) {
                __io_uring_show_fdinfo(ctx, m);
                mutex_unlock(&ctx->uring_lock);
        }
}