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

#include <linux/io_uring_types.h>

#define __wq_list_for_each(pos, head)                           \
        for (pos = (head)->first; pos; pos = (pos)->next)

#define wq_list_for_each(pos, prv, head)                        \
        for (pos = (head)->first, prv = NULL; pos; prv = pos, pos = (pos)->next)

#define wq_list_empty(list)     (READ_ONCE((list)->first) == NULL)

#define INIT_WQ_LIST(list)      do {                            \
        (list)->first = NULL;                                   \
} while (0)

static inline void wq_list_add_after(struct io_wq_work_node *node,
                                     struct io_wq_work_node *pos,
                                     struct io_wq_work_list *list)
{
        struct io_wq_work_node *next = pos->next;

        pos->next = node;
        node->next = next;
        if (!next)
                list->last = node;
}

static inline void wq_list_add_tail(struct io_wq_work_node *node,
                                    struct io_wq_work_list *list)
{
        node->next = NULL;
        if (!list->first) {
                list->last = node;
                WRITE_ONCE(list->first, node);
        } else {
                list->last->next = node;
                list->last = node;
        }
}

static inline void wq_list_cut(struct io_wq_work_list *list,
                               struct io_wq_work_node *last,
                               struct io_wq_work_node *prev)
{
        /* first in the list, if prev==NULL */
        if (!prev)
                WRITE_ONCE(list->first, last->next);
        else
                prev->next = last->next;

        if (last == list->last)
                list->last = prev;
        last->next = NULL;
}

static inline void wq_stack_add_head(struct io_wq_work_node *node,
                                     struct io_wq_work_node *stack)
{
        node->next = stack->next;
        stack->next = node;
}

static inline void wq_list_del(struct io_wq_work_list *list,
                               struct io_wq_work_node *node,
                               struct io_wq_work_node *prev)
{
        wq_list_cut(list, node, prev);
}

static inline
struct io_wq_work_node *wq_stack_extract(struct io_wq_work_node *stack)
{
        struct io_wq_work_node *node = stack->next;

        stack->next = node->next;
        return node;
}

static inline struct io_wq_work *wq_next_work(struct io_wq_work *work)
{
        if (!work->list.next)
                return NULL;

        return container_of(work->list.next, struct io_wq_work, list);
}

#endif // INTERNAL_IO_SLIST_H