1 files changed, 55 insertions, 13 deletions

diff --git a/net/core/dst_cache.c b/net/core/dst_cache.c
index 64cef977484a..9ab4902324e1 100644
--- a/net/core/dst_cache.c
+++ b/net/core/dst_cache.c
@@ -1,12 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * 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>
@@ -21,6 +17,7 @@
 struct dst_cache_pcpu {
 	unsigned long refresh_ts;
 	struct dst_entry *dst;
+	local_lock_t bh_lock;
 	u32 cookie;
 	union {
 		struct in_addr in_saddr;
@@ -31,6 +28,7 @@ struct dst_cache_pcpu {
 static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache,
 				      struct dst_entry *dst, u32 cookie)
 {
+	DEBUG_NET_WARN_ON_ONCE(!in_softirq());
 	dst_release(dst_cache->dst);
 	if (dst)
 		dst_hold(dst);
@@ -44,6 +42,7 @@ static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache,
 {
 	struct dst_entry *dst;
 
+	DEBUG_NET_WARN_ON_ONCE(!in_softirq());
 	dst = idst->dst;
 	if (!dst)
 		goto fail;
@@ -51,8 +50,9 @@ static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache,
 	/* 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)))) {
+	if (unlikely(!time_after(idst->refresh_ts,
+				 READ_ONCE(dst_cache->reset_ts)) ||
+		     (READ_ONCE(dst->obsolete) && !dst->ops->check(dst, idst->cookie)))) {
 		dst_cache_per_cpu_dst_set(idst, NULL, 0);
 		dst_release(dst);
 		goto fail;
@@ -66,10 +66,15 @@ fail:
 
 struct dst_entry *dst_cache_get(struct dst_cache *dst_cache)
 {
+	struct dst_entry *dst;
+
 	if (!dst_cache->cache)
 		return NULL;
 
-	return dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache));
+	local_lock_nested_bh(&dst_cache->cache->bh_lock);
+	dst = dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache));
+	local_unlock_nested_bh(&dst_cache->cache->bh_lock);
+	return dst;
 }
 EXPORT_SYMBOL_GPL(dst_cache_get);
 
@@ -81,13 +86,17 @@ struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr)
 	if (!dst_cache->cache)
 		return NULL;
 
+	local_lock_nested_bh(&dst_cache->cache->bh_lock);
 	idst = this_cpu_ptr(dst_cache->cache);
 	dst = dst_cache_per_cpu_get(dst_cache, idst);
-	if (!dst)
+	if (!dst) {
+		local_unlock_nested_bh(&dst_cache->cache->bh_lock);
 		return NULL;
+	}
 
 	*saddr = idst->in_saddr.s_addr;
-	return container_of(dst, struct rtable, dst);
+	local_unlock_nested_bh(&dst_cache->cache->bh_lock);
+	return dst_rtable(dst);
 }
 EXPORT_SYMBOL_GPL(dst_cache_get_ip4);
 
@@ -99,9 +108,11 @@ void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst,
 	if (!dst_cache->cache)
 		return;
 
+	local_lock_nested_bh(&dst_cache->cache->bh_lock);
 	idst = this_cpu_ptr(dst_cache->cache);
 	dst_cache_per_cpu_dst_set(idst, dst, 0);
 	idst->in_saddr.s_addr = saddr;
+	local_unlock_nested_bh(&dst_cache->cache->bh_lock);
 }
 EXPORT_SYMBOL_GPL(dst_cache_set_ip4);
 
@@ -114,10 +125,13 @@ void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst,
 	if (!dst_cache->cache)
 		return;
 
+	local_lock_nested_bh(&dst_cache->cache->bh_lock);
+
 	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));
+	dst_cache_per_cpu_dst_set(idst, dst,
+				  rt6_get_cookie(dst_rt6_info(dst)));
 	idst->in6_saddr = *saddr;
+	local_unlock_nested_bh(&dst_cache->cache->bh_lock);
 }
 EXPORT_SYMBOL_GPL(dst_cache_set_ip6);
 
@@ -130,12 +144,17 @@ struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache,
 	if (!dst_cache->cache)
 		return NULL;
 
+	local_lock_nested_bh(&dst_cache->cache->bh_lock);
+
 	idst = this_cpu_ptr(dst_cache->cache);
 	dst = dst_cache_per_cpu_get(dst_cache, idst);
-	if (!dst)
+	if (!dst) {
+		local_unlock_nested_bh(&dst_cache->cache->bh_lock);
 		return NULL;
+	}
 
 	*saddr = idst->in6_saddr;
+	local_unlock_nested_bh(&dst_cache->cache->bh_lock);
 	return dst;
 }
 EXPORT_SYMBOL_GPL(dst_cache_get_ip6);
@@ -143,10 +162,14 @@ EXPORT_SYMBOL_GPL(dst_cache_get_ip6);
 
 int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp)
 {
+	unsigned int i;
+
 	dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu,
 					    gfp | __GFP_ZERO);
 	if (!dst_cache->cache)
 		return -ENOMEM;
+	for_each_possible_cpu(i)
+		local_lock_init(&per_cpu_ptr(dst_cache->cache, i)->bh_lock);
 
 	dst_cache_reset(dst_cache);
 	return 0;
@@ -166,3 +189,22 @@ void dst_cache_destroy(struct dst_cache *dst_cache)
 	free_percpu(dst_cache->cache);
 }
 EXPORT_SYMBOL_GPL(dst_cache_destroy);
+
+void dst_cache_reset_now(struct dst_cache *dst_cache)
+{
+	int i;
+
+	if (!dst_cache->cache)
+		return;
+
+	dst_cache_reset(dst_cache);
+	for_each_possible_cpu(i) {
+		struct dst_cache_pcpu *idst = per_cpu_ptr(dst_cache->cache, i);
+		struct dst_entry *dst = idst->dst;
+
+		idst->cookie = 0;
+		idst->dst = NULL;
+		dst_release(dst);
+	}
+}
+EXPORT_SYMBOL_GPL(dst_cache_reset_now);