// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
/*
 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
 * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
 */

#include <linux/vmalloc.h>
#include "rxe.h"
#include "rxe_loc.h"
#include "rxe_queue.h"

int do_mmap_info(struct rxe_dev *rxe, struct mminfo __user *outbuf,
                 struct ib_udata *udata, struct rxe_queue_buf *buf,
                 size_t buf_size, struct rxe_mmap_info **ip_p)
{
        int err;
        struct rxe_mmap_info *ip = NULL;

        if (outbuf) {
                ip = rxe_create_mmap_info(rxe, buf_size, udata, buf);
                if (IS_ERR(ip)) {
                        err = PTR_ERR(ip);
                        goto err1;
                }

                if (copy_to_user(outbuf, &ip->info, sizeof(ip->info))) {
                        err = -EFAULT;
                        goto err2;
                }

                spin_lock_bh(&rxe->pending_lock);
                list_add(&ip->pending_mmaps, &rxe->pending_mmaps);
                spin_unlock_bh(&rxe->pending_lock);
        }

        *ip_p = ip;

        return 0;

err2:
        kfree(ip);
err1:
        return err;
}

inline void rxe_queue_reset(struct rxe_queue *q)
{
        /* queue is comprised from header and the memory
         * of the actual queue. See "struct rxe_queue_buf" in rxe_queue.h
         * reset only the queue itself and not the management header
         */
        memset(q->buf->data, 0, q->buf_size - sizeof(struct rxe_queue_buf));
}

struct rxe_queue *rxe_queue_init(struct rxe_dev *rxe, int *num_elem,
                        unsigned int elem_size, enum queue_type type)
{
        struct rxe_queue *q;
        size_t buf_size;
        unsigned int num_slots;

        /* num_elem == 0 is allowed, but uninteresting */
        if (*num_elem < 0)
                return NULL;

        q = kzalloc_obj(*q);
        if (!q)
                return NULL;

        q->rxe = rxe;
        q->type = type;

        /* used in resize, only need to copy used part of queue */
        q->elem_size = elem_size;

        /* pad element up to at least a cacheline and always a power of 2 */
        if (elem_size < cache_line_size())
                elem_size = cache_line_size();
        elem_size = roundup_pow_of_two(elem_size);

        q->log2_elem_size = order_base_2(elem_size);

        num_slots = *num_elem + 1;
        num_slots = roundup_pow_of_two(num_slots);
        q->index_mask = num_slots - 1;

        buf_size = sizeof(struct rxe_queue_buf) + num_slots * elem_size;

        q->buf = vmalloc_user(buf_size);
        if (!q->buf)
                goto err2;

        q->buf->log2_elem_size = q->log2_elem_size;
        q->buf->index_mask = q->index_mask;

        q->buf_size = buf_size;

        *num_elem = num_slots - 1;
        return q;

err2:
        kfree(q);
        return NULL;
}

/* copies elements from original q to new q and then swaps the contents of the
 * two q headers. This is so that if anyone is holding a pointer to q it will
 * still work
 */
static int resize_finish(struct rxe_queue *q, struct rxe_queue *new_q,
                         unsigned int num_elem)
{
        enum queue_type type = q->type;
        u32 new_prod;
        u32 prod;
        u32 cons;

        if (!queue_empty(q, q->type) && (num_elem < queue_count(q, type)))
                return -EINVAL;

        new_prod = queue_get_producer(new_q, type);
        prod = queue_get_producer(q, type);
        cons = queue_get_consumer(q, type);

        while ((prod - cons) & q->index_mask) {
                memcpy(queue_addr_from_index(new_q, new_prod),
                       queue_addr_from_index(q, cons), new_q->elem_size);
                new_prod = queue_next_index(new_q, new_prod);
                cons = queue_next_index(q, cons);
        }

        new_q->buf->producer_index = new_prod;
        q->buf->consumer_index = cons;

        /* update private index copies */
        if (type == QUEUE_TYPE_TO_CLIENT)
                new_q->index = new_q->buf->producer_index;
        else
                q->index = q->buf->consumer_index;

        /* exchange rxe_queue headers */
        swap(*q, *new_q);

        return 0;
}

int rxe_queue_resize(struct rxe_queue *q, unsigned int *num_elem_p,
                     unsigned int elem_size, struct ib_udata *udata,
                     struct mminfo __user *outbuf, spinlock_t *producer_lock,
                     spinlock_t *consumer_lock)
{
        struct rxe_queue *new_q;
        unsigned int num_elem = *num_elem_p;
        int err;
        unsigned long producer_flags;
        unsigned long consumer_flags;

        new_q = rxe_queue_init(q->rxe, &num_elem, elem_size, q->type);
        if (!new_q)
                return -ENOMEM;

        err = do_mmap_info(new_q->rxe, outbuf, udata, new_q->buf,
                           new_q->buf_size, &new_q->ip);
        if (err) {
                vfree(new_q->buf);
                kfree(new_q);
                goto err1;
        }

        spin_lock_irqsave(consumer_lock, consumer_flags);

        if (producer_lock) {
                spin_lock_irqsave(producer_lock, producer_flags);
                err = resize_finish(q, new_q, num_elem);
                spin_unlock_irqrestore(producer_lock, producer_flags);
        } else {
                err = resize_finish(q, new_q, num_elem);
        }

        spin_unlock_irqrestore(consumer_lock, consumer_flags);

        rxe_queue_cleanup(new_q);       /* new/old dep on err */
        if (err)
                goto err1;

        *num_elem_p = num_elem;
        return 0;

err1:
        return err;
}

void rxe_queue_cleanup(struct rxe_queue *q)
{
        if (q->ip)
                kref_put(&q->ip->ref, rxe_mmap_release);
        else
                vfree(q->buf);

        kfree(q);
}