linux-imx

/*

 * Copyright (c) 2016 Citrix Systems Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License version 2

 * as published by the Free Softare Foundation; or, when distributed

 * separately from the Linux kernel or incorporated into other

 * software packages, subject to the following license:

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this source file (the "Software"), to deal in the Software without

 * restriction, including without limitation the rights to use, copy, modify,

 * merge, publish, distribute, sublicense, and/or sell copies of the Software,

 * and to permit persons to whom the Software is furnished to do so, subject to

 * the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

​

#define XEN_NETIF_DEFINE_TOEPLITZ

​

#include "common.h"

#include <linux/vmalloc.h>

#include <linux/rculist.h>

​

static void xenvif_add_hash(struct xenvif *vif, const u8 *tag,

                unsigned int len, u32 val)

{

    struct xenvif_hash_cache_entry *new, *entry, *oldest;

    unsigned long flags;

    bool found;

​

    new = kmalloc(sizeof(*entry), GFP_ATOMIC);

    if (!new)

        return;

​

    memcpy(new->tag, tag, len);

    new->len = len;

    new->val = val;

​

    spin_lock_irqsave(&vif->hash.cache.lock, flags);

​

    found = false;

    oldest = NULL;

    list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {

        /* Make sure we don't add duplicate entries */

        if (entry->len == len &&

            memcmp(entry->tag, tag, len) == 0)

            found = true;

        if (!oldest || entry->seq < oldest->seq)

            oldest = entry;

    }

​

    if (!found) {

        new->seq = atomic_inc_return(&vif->hash.cache.seq);

        list_add_rcu(&new->link, &vif->hash.cache.list);

​

        if (++vif->hash.cache.count > xenvif_hash_cache_size) {

            list_del_rcu(&oldest->link);

            vif->hash.cache.count--;

            kfree_rcu(oldest, rcu);

        }

    }

​

    spin_unlock_irqrestore(&vif->hash.cache.lock, flags);

​

    if (found)

        kfree(new);

}

​

static u32 xenvif_new_hash(struct xenvif *vif, const u8 *data,

               unsigned int len)

{

    u32 val;

​

    val = xen_netif_toeplitz_hash(vif->hash.key,

                      sizeof(vif->hash.key),

                      data, len);

​

    if (xenvif_hash_cache_size != 0)

        xenvif_add_hash(vif, data, len, val);

​

    return val;