diff options
| author |   Eric Dumazet <edumazet@google.com> | 2022-06-23 04:34:37 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2022-06-24 11:34:37 +0100 |
| commit | 9094db4b8004fca4899852684df2a32dab15c851 (patch) | |
| tree | 1f97777c0c51517dc1c8a2624eb437aef025d7fe | |
| parent | ipmr: do not acquire mrt_lock in ioctl(SIOCGETVIFCNT) (diff) | |
| download | linux-dev-9094db4b8004fca4899852684df2a32dab15c851.tar.xz linux-dev-9094db4b8004fca4899852684df2a32dab15c851.zip | |
ipmr: do not acquire mrt_lock before calling ipmr_cache_unresolved()
rcu_read_lock() protection is good enough.
ipmr_cache_unresolved() uses a dedicated spinlock (mfc_unres_lock)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/ipmr.c | 25 |
1 files changed, 8 insertions, 17 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index bc8b7504fde6..6ea54bc3d9b6 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -680,7 +680,7 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify, if (VIF_EXISTS(mrt, tmp)) break; } - mrt->maxvif = tmp+1; + WRITE_ONCE(mrt->maxvif, tmp + 1); } write_unlock_bh(&mrt_lock); @@ -905,7 +905,7 @@ static int vif_add(struct net *net, struct mr_table *mrt, WRITE_ONCE(mrt->mroute_reg_vif_num, vifi); } if (vifi+1 > mrt->maxvif) - mrt->maxvif = vifi+1; + WRITE_ONCE(mrt->maxvif, vifi + 1); write_unlock_bh(&mrt_lock); call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev, vifi, mrt->id); @@ -1923,11 +1923,12 @@ out_free: kfree_skb(skb); } -static int ipmr_find_vif(struct mr_table *mrt, struct net_device *dev) +/* Called with mrt_lock or rcu_read_lock() */ +static int ipmr_find_vif(const struct mr_table *mrt, struct net_device *dev) { int ct; - - for (ct = mrt->maxvif-1; ct >= 0; ct--) { + /* Pairs with WRITE_ONCE() in vif_delete()/vif_add() */ + for (ct = READ_ONCE(mrt->maxvif) - 1; ct >= 0; ct--) { if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev) break; } @@ -2161,15 +2162,9 @@ int ip_mr_input(struct sk_buff *skb) skb = skb2; } - read_lock(&mrt_lock); vif = ipmr_find_vif(mrt, dev); - if (vif >= 0) { - int err2 = ipmr_cache_unresolved(mrt, vif, skb, dev); - read_unlock(&mrt_lock); - - return err2; - } - read_unlock(&mrt_lock); + if (vif >= 0) + return ipmr_cache_unresolved(mrt, vif, skb, dev); kfree_skb(skb); return -ENODEV; } @@ -2273,18 +2268,15 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb, int vif = -1; dev = skb->dev; - read_lock(&mrt_lock); if (dev) vif = ipmr_find_vif(mrt, dev); if (vif < 0) { - read_unlock(&mrt_lock); rcu_read_unlock(); return -ENODEV; } skb2 = skb_realloc_headroom(skb, sizeof(struct iphdr)); if (!skb2) { - read_unlock(&mrt_lock); rcu_read_unlock(); return -ENOMEM; } @@ -2298,7 +2290,6 @@ int ipmr_get_route(struct net *net, struct sk_buff *skb, iph->daddr = daddr; iph->version = 0; err = ipmr_cache_unresolved(mrt, vif, skb2, dev); - read_unlock(&mrt_lock); rcu_read_unlock(); return err; } |