/*
 * net/core/dst_cache.c - dst entry cache
 *
 * Copyright (c) 2016 Paolo Abeni <pabeni@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/percpu.h>
#include <net/dst_cache.h>
#include <net/route.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ip6_fib.h>
#endif
#include <uapi/linux/in.h>

struct dst_cache_pcpu {
	unsigned long refresh_ts;
	struct dst_entry *dst;
	u32 cookie;
	union {
		struct in_addr in_saddr;
		struct in6_addr in6_saddr;
	};
};

static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache,
				      struct dst_entry *dst, u32 cookie)
{
	dst_release(dst_cache->dst);
	if (dst)
		dst_hold(dst);

	dst_cache->cookie = cookie;
	dst_cache->dst = dst;
}

static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache,
					       struct dst_cache_pcpu *idst)
{
	struct dst_entry *dst;

	dst = idst->dst;
	if (!dst)
		goto fail;

	/* the cache already hold a dst reference; it can't go away */
	dst_hold(dst);

	if (unlikely(!time_after(idst->refresh_ts, dst_cache->reset_ts) ||
		     (dst->obsolete && !dst->ops->check(dst, idst->cookie)))) {
		dst_cache_per_cpu_dst_set(idst, NULL, 0);
		dst_release(dst);
		goto fail;
	}
	return dst;

fail:
	idst->refresh_ts = jiffies;
	return NULL;
}

struct dst_entry *dst_cache_get(struct dst_cache *dst_cache)
{
	if (!dst_cache->cache)
		return NULL;

	return dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache));
}
EXPORT_SYMBOL_GPL(dst_cache_get);

struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr)
{
	struct dst_cache_pcpu *idst;
	struct dst_entry *dst;

	if (!dst_cache->cache)
		return NULL;

	idst = this_cpu_ptr(dst_cache->cache);
	dst = dst_cache_per_cpu_get(dst_cache, idst);
	if (!dst)
		return NULL;

	*saddr = idst->in_saddr.s_addr;
	return container_of(dst, struct rtable, dst);
}
EXPORT_SYMBOL_GPL(dst_cache_get_ip4);

void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst,
		       __be32 saddr)
{
	struct dst_cache_pcpu *idst;

	if (!dst_cache->cache)
		return;

	idst = this_cpu_ptr(dst_cache->cache);
	dst_cache_per_cpu_dst_set(idst, dst, 0);
	idst->in_saddr.s_addr = saddr;
}
EXPORT_SYMBOL_GPL(dst_cache_set_ip4);

#if IS_ENABLED(CONFIG_IPV6)
void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst,
		       const struct in6_addr *addr)
{
	struct dst_cache_pcpu *idst;

	if (!dst_cache->cache)
		return;

	idst = this_cpu_ptr(dst_cache->cache);
	dst_cache_per_cpu_dst_set(this_cpu_ptr(dst_cache->cache), dst,
				  rt6_get_cookie((struct rt6_info *)dst));
	idst->in6_saddr = *addr;
}
EXPORT_SYMBOL_GPL(dst_cache_set_ip6);

struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache,
				    struct in6_addr *saddr)
{
	struct dst_cache_pcpu *idst;
	struct dst_entry *dst;

	if (!dst_cache->cache)
		return NULL;

	idst = this_cpu_ptr(dst_cache->cache);
	dst = dst_cache_per_cpu_get(dst_cache, idst);
	if (!dst)
		return NULL;

	*saddr = idst->in6_saddr;
	return dst;
}
EXPORT_SYMBOL_GPL(dst_cache_get_ip6);
#endif

int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp)
{
	dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu,
					    gfp | __GFP_ZERO);
	if (!dst_cache->cache)
		return -ENOMEM;

	dst_cache_reset(dst_cache);
	return 0;
}
EXPORT_SYMBOL_GPL(dst_cache_init);

void dst_cache_destroy(struct dst_cache *dst_cache)
{
	int i;

	if (!dst_cache->cache)
		return;

	for_each_possible_cpu(i)
		dst_release(per_cpu_ptr(dst_cache->cache, i)->dst);

	free_percpu(dst_cache->cache);
}
EXPORT_SYMBOL_GPL(dst_cache_destroy);
0'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Alexander Stein &lt;alexander.stein@systec-electronic.com&gt;</td><td class='right'>2017-01-30 12:35:28 +0100</td></tr>
<tr><th>committer</th><td>Linus Walleij &lt;linus.walleij@linaro.org&gt;</td><td class='right'>2017-01-30 15:53:57 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/soc/bcm2835?id=cdca06e4e85974d8a3503ab15709dbbaf90d3dd1'>cdca06e4e85974d8a3503ab15709dbbaf90d3dd1</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/soc/bcm2835?id=cdca06e4e85974d8a3503ab15709dbbaf90d3dd1'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=cdca06e4e85974d8a3503ab15709dbbaf90d3dd1'>268b0c01070a957006db97c88dccb5fb061440ff</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/soc/bcm2835?id=cdca06e4e85974d8a3503ab15709dbbaf90d3dd1'>include/soc/bcm2835</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/soc/bcm2835?id=1b89970d81bbd52720fc64a3fe9572ee33588363'>1b89970d81bbd52720fc64a3fe9572ee33588363</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/soc/bcm2835?id=cdca06e4e85974d8a3503ab15709dbbaf90d3dd1&amp;id2=1b89970d81bbd52720fc64a3fe9572ee33588363'>diff</a>)</td></tr></table>
<div class='commit-subject'>pinctrl: baytrail: Add missing spinlock usage in byt_gpio_irq_handler</div><div class='commit-msg'>According to VLI64 Intel Atom E3800 Specification Update (#329901)
concurrent read accesses may result in returning 0xffffffff and write
accesses may be dropped silently.
To workaround all accesses must be protected by locks.

Cc: stable@vger.kernel.org
Signed-off-by: Alexander Stein &lt;alexander.stein@systec-electronic.com&gt;
Acked-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=cdca06e4e85974d8a3503ab15709dbbaf90d3dd1'>Diffstat</a> (limited to 'include/soc/bcm2835')</div><table summary='diffstat' class='diffstat'>