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

#include <uapi/linux/io_uring.h>

#include "io_uring.h"
#include "alloc_cache.h"
#include "rsrc.h"
#include "kbuf.h"
#include "uring_cmd.h"
#include "poll.h"

void io_cmd_cache_free(const void *entry)
{
        struct io_async_cmd *ac = (struct io_async_cmd *)entry;

        io_vec_free(&ac->vec);
        kfree(ac);
}

static void io_req_uring_cleanup(struct io_kiocb *req, unsigned int issue_flags)
{
        struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
        struct io_async_cmd *ac = req->async_data;

        if (issue_flags & IO_URING_F_UNLOCKED)
                return;

        io_alloc_cache_vec_kasan(&ac->vec);
        if (ac->vec.nr > IO_VEC_CACHE_SOFT_CAP)
                io_vec_free(&ac->vec);

        if (io_alloc_cache_put(&req->ctx->cmd_cache, ac)) {
                ioucmd->sqe = NULL;
                io_req_async_data_clear(req, REQ_F_NEED_CLEANUP);
        }
}

void io_uring_cmd_cleanup(struct io_kiocb *req)
{
        io_req_uring_cleanup(req, 0);
}

bool io_uring_try_cancel_uring_cmd(struct io_ring_ctx *ctx,
                                   struct io_uring_task *tctx, bool cancel_all)
{
        struct hlist_node *tmp;
        struct io_kiocb *req;
        bool ret = false;

        lockdep_assert_held(&ctx->uring_lock);

        hlist_for_each_entry_safe(req, tmp, &ctx->cancelable_uring_cmd,
                        hash_node) {
                struct io_uring_cmd *cmd = io_kiocb_to_cmd(req,
                                struct io_uring_cmd);
                struct file *file = req->file;

                if (!cancel_all && req->tctx != tctx)
                        continue;

                if (cmd->flags & IORING_URING_CMD_CANCELABLE) {
                        file->f_op->uring_cmd(cmd, IO_URING_F_CANCEL |
                                                   IO_URING_F_COMPLETE_DEFER);
                        ret = true;
                }
        }
        io_submit_flush_completions(ctx);
        return ret;
}

static void io_uring_cmd_del_cancelable(struct io_uring_cmd *cmd,
                unsigned int issue_flags)
{
        struct io_kiocb *req = cmd_to_io_kiocb(cmd);
        struct io_ring_ctx *ctx = req->ctx;

        if (!(cmd->flags & IORING_URING_CMD_CANCELABLE))
                return;

        cmd->flags &= ~IORING_URING_CMD_CANCELABLE;
        io_ring_submit_lock(ctx, issue_flags);
        hlist_del(&req->hash_node);
        io_ring_submit_unlock(ctx, issue_flags);
}

/*
 * Mark this command as concelable, then io_uring_try_cancel_uring_cmd()
 * will try to cancel this issued command by sending ->uring_cmd() with
 * issue_flags of IO_URING_F_CANCEL.
 *
 * The command is guaranteed to not be done when calling ->uring_cmd()
 * with IO_URING_F_CANCEL, but it is driver's responsibility to deal
 * with race between io_uring canceling and normal completion.
 */
void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd,
                unsigned int issue_flags)
{
        struct io_kiocb *req = cmd_to_io_kiocb(cmd);
        struct io_ring_ctx *ctx = req->ctx;

        /*
         * Doing cancelations on IOPOLL requests are not supported. Both
         * because they can't get canceled in the block stack, but also
         * because iopoll completion data overlaps with the hash_node used
         * for tracking.
         */
        if (ctx->flags & IORING_SETUP_IOPOLL)
                return;

        if (!(cmd->flags & IORING_URING_CMD_CANCELABLE)) {
                cmd->flags |= IORING_URING_CMD_CANCELABLE;
                io_ring_submit_lock(ctx, issue_flags);
                hlist_add_head(&req->hash_node, &ctx->cancelable_uring_cmd);
                io_ring_submit_unlock(ctx, issue_flags);
        }
}
EXPORT_SYMBOL_GPL(io_uring_cmd_mark_cancelable);

void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd,
                        io_req_tw_func_t task_work_cb,
                        unsigned flags)
{
        struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);

        if (WARN_ON_ONCE(req->flags & REQ_F_APOLL_MULTISHOT))
                return;

        req->io_task_work.func = task_work_cb;
        __io_req_task_work_add(req, flags);
}
EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task);

static inline void io_req_set_cqe32_extra(struct io_kiocb *req,
                                          u64 extra1, u64 extra2)
{
        req->big_cqe.extra1 = extra1;
        req->big_cqe.extra2 = extra2;
}

/*
 * Called by consumers of io_uring_cmd, if they originally returned
 * -EIOCBQUEUED upon receiving the command.
 */
void __io_uring_cmd_done(struct io_uring_cmd *ioucmd, s32 ret, u64 res2,
                       unsigned issue_flags, bool is_cqe32)
{
        struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);

        if (WARN_ON_ONCE(req->flags & REQ_F_APOLL_MULTISHOT))
                return;

        io_uring_cmd_del_cancelable(ioucmd, issue_flags);

        if (ret < 0)
                req_set_fail(req);

        io_req_set_res(req, ret, 0);
        if (is_cqe32) {
                if (req->ctx->flags & IORING_SETUP_CQE_MIXED)
                        req->cqe.flags |= IORING_CQE_F_32;
                io_req_set_cqe32_extra(req, res2, 0);
        }
        io_req_uring_cleanup(req, issue_flags);
        if (req->ctx->flags & IORING_SETUP_IOPOLL) {
                /* order with io_iopoll_req_issued() checking ->iopoll_complete */
                smp_store_release(&req->iopoll_completed, 1);
        } else if (issue_flags & IO_URING_F_COMPLETE_DEFER) {
                if (WARN_ON_ONCE(issue_flags & IO_URING_F_UNLOCKED))
                        return;
                io_req_complete_defer(req);
        } else {
                req->io_task_work.func = io_req_task_complete;
                io_req_task_work_add(req);
        }
}
EXPORT_SYMBOL_GPL(__io_uring_cmd_done);

int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
        struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
        struct io_async_cmd *ac;

        if (sqe->__pad1)
                return -EINVAL;

        ioucmd->flags = READ_ONCE(sqe->uring_cmd_flags);
        if (ioucmd->flags & ~IORING_URING_CMD_MASK)
                return -EINVAL;

        if (ioucmd->flags & IORING_URING_CMD_FIXED) {
                if (ioucmd->flags & IORING_URING_CMD_MULTISHOT)
                        return -EINVAL;
                req->buf_index = READ_ONCE(sqe->buf_index);
        }

        if (!!(ioucmd->flags & IORING_URING_CMD_MULTISHOT) !=
            !!(req->flags & REQ_F_BUFFER_SELECT))
                return -EINVAL;

        ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);

        ac = io_uring_alloc_async_data(&req->ctx->cmd_cache, req);
        if (!ac)
                return -ENOMEM;
        ioucmd->sqe = sqe;
        return 0;
}

/*
 * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
 * slot.
 */
static inline size_t uring_sqe_size(struct io_kiocb *req)
{
        if (req->ctx->flags & IORING_SETUP_SQE128 ||
            req->opcode == IORING_OP_URING_CMD128)
                return 2 * sizeof(struct io_uring_sqe);
        return sizeof(struct io_uring_sqe);
}

void io_uring_cmd_sqe_copy(struct io_kiocb *req)
{
        struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
        struct io_async_cmd *ac = req->async_data;

        /* Should not happen, as REQ_F_SQE_COPIED covers this */
        if (WARN_ON_ONCE(ioucmd->sqe == ac->sqes))
                return;
        memcpy(ac->sqes, ioucmd->sqe, uring_sqe_size(req));
        ioucmd->sqe = ac->sqes;
}

int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
{
        struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
        struct io_ring_ctx *ctx = req->ctx;
        struct file *file = req->file;
        int ret;

        if (!file->f_op->uring_cmd)
                return -EOPNOTSUPP;

        ret = security_uring_cmd(ioucmd);
        if (ret)
                return ret;

        if (ctx->flags & IORING_SETUP_SQE128 ||
            req->opcode == IORING_OP_URING_CMD128)
                issue_flags |= IO_URING_F_SQE128;
        if (ctx->flags & (IORING_SETUP_CQE32 | IORING_SETUP_CQE_MIXED))
                issue_flags |= IO_URING_F_CQE32;
        if (io_is_compat(ctx))
                issue_flags |= IO_URING_F_COMPAT;
        if (ctx->flags & IORING_SETUP_IOPOLL) {
                if (!file->f_op->uring_cmd_iopoll)
                        return -EOPNOTSUPP;
                issue_flags |= IO_URING_F_IOPOLL;
                req->iopoll_completed = 0;
                if (ctx->flags & IORING_SETUP_HYBRID_IOPOLL) {
                        /* make sure every req only blocks once */
                        req->flags &= ~REQ_F_IOPOLL_STATE;
                        req->iopoll_start = ktime_get_ns();
                }
        }

        ret = file->f_op->uring_cmd(ioucmd, issue_flags);
        if (ioucmd->flags & IORING_URING_CMD_MULTISHOT) {
                if (ret >= 0)
                        return IOU_ISSUE_SKIP_COMPLETE;
        }
        if (ret == -EAGAIN) {
                ioucmd->flags |= IORING_URING_CMD_REISSUE;
                return ret;
        }
        if (ret == -EIOCBQUEUED)
                return ret;
        if (ret < 0)
                req_set_fail(req);
        io_req_uring_cleanup(req, issue_flags);
        io_req_set_res(req, ret, 0);
        return IOU_COMPLETE;
}

int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
                              struct iov_iter *iter,
                              struct io_uring_cmd *ioucmd,
                              unsigned int issue_flags)
{
        struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);

        if (WARN_ON_ONCE(!(ioucmd->flags & IORING_URING_CMD_FIXED)))
                return -EINVAL;

        return io_import_reg_buf(req, iter, ubuf, len, rw, issue_flags);
}
EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);

int io_uring_cmd_import_fixed_vec(struct io_uring_cmd *ioucmd,
                                  const struct iovec __user *uvec,
                                  size_t uvec_segs,
                                  int ddir, struct iov_iter *iter,
                                  unsigned issue_flags)
{
        struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
        struct io_async_cmd *ac = req->async_data;
        int ret;

        if (WARN_ON_ONCE(!(ioucmd->flags & IORING_URING_CMD_FIXED)))
                return -EINVAL;

        ret = io_prep_reg_iovec(req, &ac->vec, uvec, uvec_segs);
        if (ret)
                return ret;

        return io_import_reg_vec(ddir, iter, req, &ac->vec, uvec_segs,
                                 issue_flags);
}
EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed_vec);

void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd)
{
        struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);

        io_req_queue_iowq(req);
}

int io_cmd_poll_multishot(struct io_uring_cmd *cmd,
                          unsigned int issue_flags, __poll_t mask)
{
        struct io_kiocb *req = cmd_to_io_kiocb(cmd);
        int ret;

        if (likely(req->flags & REQ_F_APOLL_MULTISHOT))
                return 0;

        req->flags |= REQ_F_APOLL_MULTISHOT;
        mask &= ~EPOLLONESHOT;

        ret = io_arm_apoll(req, issue_flags, mask);
        return ret == IO_APOLL_OK ? -EIOCBQUEUED : -ECANCELED;
}

bool io_uring_cmd_post_mshot_cqe32(struct io_uring_cmd *cmd,
                                   unsigned int issue_flags,
                                   struct io_uring_cqe cqe[2])
{
        struct io_kiocb *req = cmd_to_io_kiocb(cmd);

        if (WARN_ON_ONCE(!(issue_flags & IO_URING_F_MULTISHOT)))
                return false;
        return io_req_post_cqe32(req, cqe);
}

/*
 * Work with io_uring_mshot_cmd_post_cqe() together for committing the
 * provided buffer upfront
 */
struct io_br_sel io_uring_cmd_buffer_select(struct io_uring_cmd *ioucmd,
                                            unsigned buf_group, size_t *len,
                                            unsigned int issue_flags)
{
        struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);

        if (!(ioucmd->flags & IORING_URING_CMD_MULTISHOT))
                return (struct io_br_sel) { .val = -EINVAL };

        if (WARN_ON_ONCE(!io_do_buffer_select(req)))
                return (struct io_br_sel) { .val = -EINVAL };

        return io_buffer_select(req, len, buf_group, issue_flags);
}
EXPORT_SYMBOL_GPL(io_uring_cmd_buffer_select);

/*
 * Return true if this multishot uring_cmd needs to be completed, otherwise
 * the event CQE is posted successfully.
 *
 * This function must use `struct io_br_sel` returned from
 * io_uring_cmd_buffer_select() for committing the buffer in the same
 * uring_cmd submission context.
 */
bool io_uring_mshot_cmd_post_cqe(struct io_uring_cmd *ioucmd,
                                 struct io_br_sel *sel, unsigned int issue_flags)
{
        struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
        unsigned int cflags = 0;

        if (!(ioucmd->flags & IORING_URING_CMD_MULTISHOT))
                return true;

        if (sel->val > 0) {
                cflags = io_put_kbuf(req, sel->val, sel->buf_list);
                if (io_req_post_cqe(req, sel->val, cflags | IORING_CQE_F_MORE))
                        return false;
        }

        io_kbuf_recycle(req, sel->buf_list, issue_flags);
        if (sel->val < 0)
                req_set_fail(req);
        io_req_set_res(req, sel->val, cflags);
        return true;
}
EXPORT_SYMBOL_GPL(io_uring_mshot_cmd_post_cqe);