/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef _LINUX_IO_URING_CMD_H
#define _LINUX_IO_URING_CMD_H

#include <uapi/linux/io_uring.h>
#include <linux/io_uring_types.h>
#include <linux/blk-mq.h>

/* only top 8 bits of sqe->uring_cmd_flags for kernel internal use */
#define IORING_URING_CMD_CANCELABLE     (1U << 30)
/* io_uring_cmd is being issued again */
#define IORING_URING_CMD_REISSUE        (1U << 31)

struct io_uring_cmd {
        struct file     *file;
        const struct io_uring_sqe *sqe;
        u32             cmd_op;
        u32             flags;
        u8              pdu[32]; /* available inline for free use */
        u8              unused[8];
};

#define io_uring_sqe128_cmd(sqe, type)  ({                                      \
        BUILD_BUG_ON(sizeof(type) > ((2 * sizeof(struct io_uring_sqe)) -        \
                                     offsetof(struct io_uring_sqe, cmd)));      \
        (const type *)(sqe)->cmd;                                               \
})

#define io_uring_sqe_cmd(sqe, type)     ({                                      \
        BUILD_BUG_ON(sizeof(type) > (sizeof(struct io_uring_sqe) -              \
                                     offsetof(struct io_uring_sqe, cmd)));      \
        (const type *)(sqe)->cmd;                                               \
})

static inline void io_uring_cmd_private_sz_check(size_t cmd_sz)
{
        BUILD_BUG_ON(cmd_sz > sizeof_field(struct io_uring_cmd, pdu));
}
#define io_uring_cmd_to_pdu(cmd, pdu_type) ( \
        io_uring_cmd_private_sz_check(sizeof(pdu_type)), \
        ((pdu_type *)&(cmd)->pdu) \
)

#if defined(CONFIG_IO_URING)
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);
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);

/*
 * Completes the request, i.e. posts an io_uring CQE and deallocates @ioucmd
 * and the corresponding io_uring request.
 *
 * Note: the caller should never hard code @issue_flags and is only allowed
 * to pass the mask provided by the core io_uring code.
 */
void __io_uring_cmd_done(struct io_uring_cmd *cmd, s32 ret, u64 res2,
                         unsigned issue_flags, bool is_cqe32);

void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd,
                            io_req_tw_func_t task_work_cb,
                            unsigned flags);

/*
 * Note: the caller should never hard code @issue_flags and only use the
 * mask provided by the core io_uring code.
 */
void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd,
                unsigned int issue_flags);

/* Execute the request from a blocking context */
void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd);

/*
 * Select a buffer from the provided buffer group for multishot uring_cmd.
 * Returns the selected buffer address and size.
 */
struct io_br_sel io_uring_cmd_buffer_select(struct io_uring_cmd *ioucmd,
                                            unsigned buf_group, size_t *len,
                                            unsigned int issue_flags);

/*
 * Complete a multishot uring_cmd event. This will post a CQE to the completion
 * queue and update the provided buffer.
 */
bool io_uring_mshot_cmd_post_cqe(struct io_uring_cmd *ioucmd,
                                 struct io_br_sel *sel, unsigned int issue_flags);

#else
static inline 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)
{
        return -EOPNOTSUPP;
}
static inline 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)
{
        return -EOPNOTSUPP;
}
static inline void __io_uring_cmd_done(struct io_uring_cmd *cmd, s32 ret,
                u64 ret2, unsigned issue_flags, bool is_cqe32)
{
}
static inline void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd,
                            io_req_tw_func_t task_work_cb, unsigned flags)
{
}
static inline void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd,
                unsigned int issue_flags)
{
}
static inline void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd)
{
}
static inline struct io_br_sel
io_uring_cmd_buffer_select(struct io_uring_cmd *ioucmd, unsigned buf_group,
                           size_t *len, unsigned int issue_flags)
{
        return (struct io_br_sel) { .val = -EOPNOTSUPP };
}
static inline bool io_uring_mshot_cmd_post_cqe(struct io_uring_cmd *ioucmd,
                                struct io_br_sel *sel, unsigned int issue_flags)
{
        return true;
}
#endif

static inline struct io_uring_cmd *io_uring_cmd_from_tw(struct io_tw_req tw_req)
{
        return io_kiocb_to_cmd(tw_req.req, struct io_uring_cmd);
}

/* task_work executor checks the deferred list completion */
#define IO_URING_CMD_TASK_WORK_ISSUE_FLAGS IO_URING_F_COMPLETE_DEFER

/* users must follow the IOU_F_TWQ_LAZY_WAKE semantics */
static inline void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd,
                        io_req_tw_func_t task_work_cb)
{
        __io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE);
}

static inline void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd,
                        io_req_tw_func_t task_work_cb)
{
        __io_uring_cmd_do_in_task(ioucmd, task_work_cb, 0);
}

static inline struct task_struct *io_uring_cmd_get_task(struct io_uring_cmd *cmd)
{
        return cmd_to_io_kiocb(cmd)->tctx->task;
}

/*
 * Return uring_cmd's context reference as its context handle for driver to
 * track per-context resource, such as registered kernel IO buffer
 */
static inline void *io_uring_cmd_ctx_handle(struct io_uring_cmd *cmd)
{
        return cmd_to_io_kiocb(cmd)->ctx;
}

static inline void io_uring_cmd_done(struct io_uring_cmd *ioucmd, s32 ret,
                                     unsigned issue_flags)
{
        return __io_uring_cmd_done(ioucmd, ret, 0, issue_flags, false);
}

static inline void io_uring_cmd_done32(struct io_uring_cmd *ioucmd, s32 ret,
                                       u64 res2, unsigned issue_flags)
{
        return __io_uring_cmd_done(ioucmd, ret, res2, issue_flags, true);
}

int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
                            void (*release)(void *), unsigned int index,
                            unsigned int issue_flags);
int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, unsigned int index,
                              unsigned int issue_flags);

#endif /* _LINUX_IO_URING_CMD_H */