From a8c9486b816f74d4645144db9e8fa2f711c1fc4b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 1 Oct 2010 16:15:08 +0000 Subject: [PATCH] ipmr: RCU protection for mfc_cache_array Use RCU & RTNL protection for mfc_cache_array[] ipmr_cache_find() is called under rcu_read_lock(); Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/mroute.h | 1 + net/ipv4/ipmr.c | 87 +++++++++++++++++++++++------------------- 2 files changed, 48 insertions(+), 40 deletions(-) diff --git a/include/linux/mroute.h b/include/linux/mroute.h index fa04b246c9a..0fa7a3a874c 100644 --- a/include/linux/mroute.h +++ b/include/linux/mroute.h @@ -213,6 +213,7 @@ struct mfc_cache { unsigned char ttls[MAXVIFS]; /* TTL thresholds */ } res; } mfc_un; + struct rcu_head rcu; }; #define MFC_STATIC 1 diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index e2db2ea616f..cbb6dabe024 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -577,11 +577,18 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify, return 0; } -static inline void ipmr_cache_free(struct mfc_cache *c) +static void ipmr_cache_free_rcu(struct rcu_head *head) { + struct mfc_cache *c = container_of(head, struct mfc_cache, rcu); + kmem_cache_free(mrt_cachep, c); } +static inline void ipmr_cache_free(struct mfc_cache *c) +{ + call_rcu(&c->rcu, ipmr_cache_free_rcu); +} + /* Destroy an unresolved cache entry, killing queued skbs and reporting error to netlink readers. */ @@ -781,6 +788,7 @@ static int vif_add(struct net *net, struct mr_table *mrt, return 0; } +/* called with rcu_read_lock() */ static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt, __be32 origin, __be32 mcastgrp) @@ -788,7 +796,7 @@ static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt, int line = MFC_HASH(mcastgrp, origin); struct mfc_cache *c; - list_for_each_entry(c, &mrt->mfc_cache_array[line], list) { + list_for_each_entry_rcu(c, &mrt->mfc_cache_array[line], list) { if (c->mfc_origin == origin && c->mfc_mcastgrp == mcastgrp) return c; } @@ -801,19 +809,20 @@ static struct mfc_cache *ipmr_cache_find(struct mr_table *mrt, static struct mfc_cache *ipmr_cache_alloc(void) { struct mfc_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_KERNEL); - if (c == NULL) - return NULL; - c->mfc_un.res.minvif = MAXVIFS; + + if (c) + c->mfc_un.res.minvif = MAXVIFS; return c; } static struct mfc_cache *ipmr_cache_alloc_unres(void) { struct mfc_cache *c = kmem_cache_zalloc(mrt_cachep, GFP_ATOMIC); - if (c == NULL) - return NULL; - skb_queue_head_init(&c->mfc_un.unres.unresolved); - c->mfc_un.unres.expires = jiffies + 10*HZ; + + if (c) { + skb_queue_head_init(&c->mfc_un.unres.unresolved); + c->mfc_un.unres.expires = jiffies + 10*HZ; + } return c; } @@ -1040,9 +1049,7 @@ static int ipmr_mfc_delete(struct mr_table *mrt, struct mfcctl *mfc) list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[line], list) { if (c->mfc_origin == mfc->mfcc_origin.s_addr && c->mfc_mcastgrp == mfc->mfcc_mcastgrp.s_addr) { - write_lock_bh(&mrt_lock); - list_del(&c->list); - write_unlock_bh(&mrt_lock); + list_del_rcu(&c->list); ipmr_cache_free(c); return 0; @@ -1095,9 +1102,7 @@ static int ipmr_mfc_add(struct net *net, struct mr_table *mrt, if (!mrtsock) c->mfc_flags |= MFC_STATIC; - write_lock_bh(&mrt_lock); - list_add(&c->list, &mrt->mfc_cache_array[line]); - write_unlock_bh(&mrt_lock); + list_add_rcu(&c->list, &mrt->mfc_cache_array[line]); /* * Check to see if we resolved a queued list. If so we @@ -1149,12 +1154,9 @@ static void mroute_clean_tables(struct mr_table *mrt) */ for (i = 0; i < MFC_LINES; i++) { list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[i], list) { - if (c->mfc_flags&MFC_STATIC) + if (c->mfc_flags & MFC_STATIC) continue; - write_lock_bh(&mrt_lock); - list_del(&c->list); - write_unlock_bh(&mrt_lock); - + list_del_rcu(&c->list); ipmr_cache_free(c); } } @@ -1422,19 +1424,19 @@ int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg) if (copy_from_user(&sr, arg, sizeof(sr))) return -EFAULT; - read_lock(&mrt_lock); + rcu_read_lock(); c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr); if (c) { sr.pktcnt = c->mfc_un.res.pkt; sr.bytecnt = c->mfc_un.res.bytes; sr.wrong_if = c->mfc_un.res.wrong_if; - read_unlock(&mrt_lock); + rcu_read_unlock(); if (copy_to_user(arg, &sr, sizeof(sr))) return -EFAULT; return 0; } - read_unlock(&mrt_lock); + rcu_read_unlock(); return -EADDRNOTAVAIL; default: return -ENOIOCTLCMD; @@ -1764,7 +1766,7 @@ int ip_mr_input(struct sk_buff *skb) } } - read_lock(&mrt_lock); + /* already under rcu_read_lock() */ cache = ipmr_cache_find(mrt, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr); /* @@ -1776,13 +1778,12 @@ int ip_mr_input(struct sk_buff *skb) if (local) { struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); ip_local_deliver(skb); - if (skb2 == NULL) { - read_unlock(&mrt_lock); + if (skb2 == NULL) return -ENOBUFS; - } skb = skb2; } + read_lock(&mrt_lock); vif = ipmr_find_vif(mrt, skb->dev); if (vif >= 0) { int err2 = ipmr_cache_unresolved(mrt, vif, skb); @@ -1795,8 +1796,8 @@ int ip_mr_input(struct sk_buff *skb) return -ENODEV; } + read_lock(&mrt_lock); ip_mr_forward(net, mrt, skb, cache, local); - read_unlock(&mrt_lock); if (local) @@ -1963,7 +1964,7 @@ int ipmr_get_route(struct net *net, if (mrt == NULL) return -ENOENT; - read_lock(&mrt_lock); + rcu_read_lock(); cache = ipmr_cache_find(mrt, rt->rt_src, rt->rt_dst); if (cache == NULL) { @@ -1973,18 +1974,21 @@ int ipmr_get_route(struct net *net, int vif; if (nowait) { - read_unlock(&mrt_lock); + rcu_read_unlock(); return -EAGAIN; } dev = skb->dev; + read_lock(&mrt_lock); if (dev == NULL || (vif = ipmr_find_vif(mrt, dev)) < 0) { read_unlock(&mrt_lock); + rcu_read_unlock(); return -ENODEV; } skb2 = skb_clone(skb, GFP_ATOMIC); if (!skb2) { read_unlock(&mrt_lock); + rcu_read_unlock(); return -ENOMEM; } @@ -1997,13 +2001,16 @@ int ipmr_get_route(struct net *net, iph->version = 0; err = ipmr_cache_unresolved(mrt, vif, skb2); read_unlock(&mrt_lock); + rcu_read_unlock(); return err; } - if (!nowait && (rtm->rtm_flags&RTM_F_NOTIFY)) + read_lock(&mrt_lock); + if (!nowait && (rtm->rtm_flags & RTM_F_NOTIFY)) cache->mfc_flags |= MFC_NOTIFY; err = __ipmr_fill_mroute(mrt, skb, cache, rtm); read_unlock(&mrt_lock); + rcu_read_unlock(); return err; } @@ -2055,14 +2062,14 @@ static int ipmr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb) s_h = cb->args[1]; s_e = cb->args[2]; - read_lock(&mrt_lock); + rcu_read_lock(); ipmr_for_each_table(mrt, net) { if (t < s_t) goto next_table; if (t > s_t) s_h = 0; for (h = s_h; h < MFC_LINES; h++) { - list_for_each_entry(mfc, &mrt->mfc_cache_array[h], list) { + list_for_each_entry_rcu(mfc, &mrt->mfc_cache_array[h], list) { if (e < s_e) goto next_entry; if (ipmr_fill_mroute(mrt, skb, @@ -2080,7 +2087,7 @@ next_table: t++; } done: - read_unlock(&mrt_lock); + rcu_read_unlock(); cb->args[2] = e; cb->args[1] = h; @@ -2213,14 +2220,14 @@ static struct mfc_cache *ipmr_mfc_seq_idx(struct net *net, struct mr_table *mrt = it->mrt; struct mfc_cache *mfc; - read_lock(&mrt_lock); + rcu_read_lock(); for (it->ct = 0; it->ct < MFC_LINES; it->ct++) { it->cache = &mrt->mfc_cache_array[it->ct]; - list_for_each_entry(mfc, it->cache, list) + list_for_each_entry_rcu(mfc, it->cache, list) if (pos-- == 0) return mfc; } - read_unlock(&mrt_lock); + rcu_read_unlock(); spin_lock_bh(&mfc_unres_lock); it->cache = &mrt->mfc_unres_queue; @@ -2279,7 +2286,7 @@ static void *ipmr_mfc_seq_next(struct seq_file *seq, void *v, loff_t *pos) } /* exhausted cache_array, show unresolved */ - read_unlock(&mrt_lock); + rcu_read_unlock(); it->cache = &mrt->mfc_unres_queue; it->ct = 0; @@ -2302,7 +2309,7 @@ static void ipmr_mfc_seq_stop(struct seq_file *seq, void *v) if (it->cache == &mrt->mfc_unres_queue) spin_unlock_bh(&mfc_unres_lock); else if (it->cache == &mrt->mfc_cache_array[it->ct]) - read_unlock(&mrt_lock); + rcu_read_unlock(); } static int ipmr_mfc_seq_show(struct seq_file *seq, void *v) @@ -2426,7 +2433,7 @@ int __init ip_mr_init(void) mrt_cachep = kmem_cache_create("ip_mrt_cache", sizeof(struct mfc_cache), - 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, + 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); if (!mrt_cachep) return -ENOMEM; -- 2.39.3