// SPDX-License-Identifier: GPL-2.0
/* XDP user-space ring structure
 * Copyright(c) 2018 Intel Corporation.
 */

#include <linux/log2.h>
#include <linux/slab.h>
#include <linux/overflow.h>
#include <linux/vmalloc.h>
#include <net/xdp_sock_drv.h>

#include "xsk_queue.h"

static size_t xskq_get_ring_size(struct xsk_queue *q, bool umem_queue)
{
        struct xdp_umem_ring *umem_ring;
        struct xdp_rxtx_ring *rxtx_ring;

        if (umem_queue)
                return struct_size(umem_ring, desc, q->nentries);
        return struct_size(rxtx_ring, desc, q->nentries);
}

struct xsk_queue *xskq_create(u32 nentries, bool umem_queue)
{
        struct xsk_queue *q;
        size_t size;

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

        q->nentries = nentries;
        q->ring_mask = nentries - 1;

        size = xskq_get_ring_size(q, umem_queue);

        /* size which is overflowing or close to SIZE_MAX will become 0 in
         * PAGE_ALIGN(), checking SIZE_MAX is enough due to the previous
         * is_power_of_2(), the rest will be handled by vmalloc_user()
         */
        if (unlikely(size == SIZE_MAX)) {
                kfree(q);
                return NULL;
        }

        size = PAGE_ALIGN(size);

        q->ring = vmalloc_user(size);
        if (!q->ring) {
                kfree(q);
                return NULL;
        }

        q->ring_vmalloc_size = size;
        return q;
}

void xskq_destroy(struct xsk_queue *q)
{
        if (!q)
                return;

        vfree(q->ring);
        kfree(q);
}