// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (C) 2019 Samsung Electronics Co., Ltd.
 */

#include <linux/list.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

#include "server.h"
#include "connection.h"
#include "ksmbd_work.h"
#include "mgmt/ksmbd_ida.h"

static struct kmem_cache *work_cache;
static struct workqueue_struct *ksmbd_wq;

struct ksmbd_work *ksmbd_alloc_work_struct(void)
{
        struct ksmbd_work *work = kmem_cache_zalloc(work_cache, KSMBD_DEFAULT_GFP);

        if (work) {
                work->compound_fid = KSMBD_NO_FID;
                work->compound_pfid = KSMBD_NO_FID;
                INIT_LIST_HEAD(&work->request_entry);
                INIT_LIST_HEAD(&work->async_request_entry);
                INIT_LIST_HEAD(&work->fp_entry);
                INIT_LIST_HEAD(&work->aux_read_list);
                work->iov_alloc_cnt = 4;
                work->iov = kzalloc_objs(struct kvec, work->iov_alloc_cnt,
                                         KSMBD_DEFAULT_GFP);
                if (!work->iov) {
                        kmem_cache_free(work_cache, work);
                        work = NULL;
                }
        }
        return work;
}

void ksmbd_free_work_struct(struct ksmbd_work *work)
{
        struct aux_read *ar, *tmp;

        WARN_ON(work->saved_cred != NULL);

        kvfree(work->response_buf);

        list_for_each_entry_safe(ar, tmp, &work->aux_read_list, entry) {
                kvfree(ar->buf);
                list_del(&ar->entry);
                kfree(ar);
        }

        kfree(work->tr_buf);
        kvfree(work->request_buf);
        kfree(work->iov);

        if (work->async_id)
                ksmbd_release_id(&work->conn->async_ida, work->async_id);
        kmem_cache_free(work_cache, work);
}

void ksmbd_work_pool_destroy(void)
{
        kmem_cache_destroy(work_cache);
}

int ksmbd_work_pool_init(void)
{
        work_cache = kmem_cache_create("ksmbd_work_cache",
                                       sizeof(struct ksmbd_work), 0,
                                       SLAB_HWCACHE_ALIGN, NULL);
        if (!work_cache)
                return -ENOMEM;
        return 0;
}

int ksmbd_workqueue_init(void)
{
        ksmbd_wq = alloc_workqueue("ksmbd-io", WQ_PERCPU, 0);
        if (!ksmbd_wq)
                return -ENOMEM;
        return 0;
}

void ksmbd_workqueue_destroy(void)
{
        destroy_workqueue(ksmbd_wq);
        ksmbd_wq = NULL;
}

bool ksmbd_queue_work(struct ksmbd_work *work)
{
        return queue_work(ksmbd_wq, &work->work);
}

static inline void __ksmbd_iov_pin(struct ksmbd_work *work, void *ib,
                                   unsigned int ib_len)
{
        work->iov[++work->iov_idx].iov_base = ib;
        work->iov[work->iov_idx].iov_len = ib_len;
        work->iov_cnt++;
}

static int __ksmbd_iov_pin_rsp(struct ksmbd_work *work, void *ib, int len,
                               void *aux_buf, unsigned int aux_size)
{
        struct aux_read *ar = NULL;
        int need_iov_cnt = 1;

        if (aux_size) {
                need_iov_cnt++;
                ar = kmalloc_obj(struct aux_read, KSMBD_DEFAULT_GFP);
                if (!ar)
                        return -ENOMEM;
        }

        if (work->iov_alloc_cnt < work->iov_cnt + need_iov_cnt) {
                struct kvec *new;

                work->iov_alloc_cnt += 4;
                new = krealloc(work->iov,
                               sizeof(struct kvec) * work->iov_alloc_cnt,
                               KSMBD_DEFAULT_GFP | __GFP_ZERO);
                if (!new) {
                        kfree(ar);
                        work->iov_alloc_cnt -= 4;
                        return -ENOMEM;
                }
                work->iov = new;
        }

        /* Plus rfc_length size on first iov */
        if (!work->iov_idx) {
                work->iov[work->iov_idx].iov_base = work->response_buf;
                *(__be32 *)work->iov[0].iov_base = 0;
                work->iov[work->iov_idx].iov_len = 4;
                work->iov_cnt++;
        }

        __ksmbd_iov_pin(work, ib, len);
        inc_rfc1001_len(work->iov[0].iov_base, len);

        if (aux_size) {
                __ksmbd_iov_pin(work, aux_buf, aux_size);
                inc_rfc1001_len(work->iov[0].iov_base, aux_size);

                ar->buf = aux_buf;
                list_add(&ar->entry, &work->aux_read_list);
        }

        return 0;
}

int ksmbd_iov_pin_rsp(struct ksmbd_work *work, void *ib, int len)
{
        return __ksmbd_iov_pin_rsp(work, ib, len, NULL, 0);
}

int ksmbd_iov_pin_rsp_read(struct ksmbd_work *work, void *ib, int len,
                           void *aux_buf, unsigned int aux_size)
{
        return __ksmbd_iov_pin_rsp(work, ib, len, aux_buf, aux_size);
}

int allocate_interim_rsp_buf(struct ksmbd_work *work)
{
        work->response_buf = kzalloc(MAX_CIFS_SMALL_BUFFER_SIZE, KSMBD_DEFAULT_GFP);
        if (!work->response_buf)
                return -ENOMEM;
        work->response_sz = MAX_CIFS_SMALL_BUFFER_SIZE;
        return 0;
}