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From: Kuniyuki Iwashima To: "David S . Miller" , David Ahern , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Kuniyuki Iwashima , Kuniyuki Iwashima , netdev@vger.kernel.org Content-Type: text/plain; charset="UTF-8" mr6_msgsize() calculates skb size needed for ip6mr_fill_mroute(). The size differs based on mrt->maxvif. We will drop RTNL for ip6mr_rtm_getroute() and mrt->maxvif may change under RCU. To avoid -EMSGSIZE, let's calculate the size with the maximum value of mrt->maxvif, MAXMIFS. struct rtnexthop is 8 bytes and MAXMIFS is 32, so the maximum delta is 256 bytes, which is small enough. Signed-off-by: Kuniyuki Iwashima --- net/ipv6/ip6mr.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index b263d3c69a5a..7ea572db9075 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -2539,7 +2539,7 @@ static int _ip6mr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb, cmd, flags); } -static int mr6_msgsize(bool unresolved, int maxvif) +static int mr6_msgsize(bool unresolved) { size_t len = NLMSG_ALIGN(sizeof(struct rtmsg)) @@ -2552,7 +2552,7 @@ static int mr6_msgsize(bool unresolved, int maxvif) len = len + nla_total_size(4) /* RTA_IIF */ + nla_total_size(0) /* RTA_MULTIPATH */ - + maxvif * NLA_ALIGN(sizeof(struct rtnexthop)) + + MAXMIFS * NLA_ALIGN(sizeof(struct rtnexthop)) /* RTA_MFC_STATS */ + nla_total_size_64bit(sizeof(struct rta_mfc_stats)) ; @@ -2567,8 +2567,7 @@ static void mr6_netlink_event(struct mr_table *mrt, struct mfc6_cache *mfc, struct sk_buff *skb; int err = -ENOBUFS; - skb = nlmsg_new(mr6_msgsize(mfc->_c.mfc_parent >= MAXMIFS, mrt->maxvif), - GFP_ATOMIC); + skb = nlmsg_new(mr6_msgsize(mfc->_c.mfc_parent >= MAXMIFS), GFP_ATOMIC); if (!skb) goto errout; @@ -2724,7 +2723,7 @@ static int ip6mr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, return -ENOENT; } - skb = nlmsg_new(mr6_msgsize(false, mrt->maxvif), GFP_KERNEL); + skb = nlmsg_new(mr6_msgsize(false), GFP_KERNEL); if (!skb) return -ENOBUFS; -- 2.53.0.1213.gd9a14994de-goog