Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932685AbZJAO26 (ORCPT ); Thu, 1 Oct 2009 10:28:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932662AbZJAO25 (ORCPT ); Thu, 1 Oct 2009 10:28:57 -0400 Received: from victor.provo.novell.com ([137.65.250.26]:51368 "EHLO victor.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932481AbZJAO24 (ORCPT ); Thu, 1 Oct 2009 10:28:56 -0400 From: Suresh Jayaraman To: Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: netdev@vger.kernel.org, Neil Brown , Miklos Szeredi , Wouter Verhelst , Peter Zijlstra , trond.myklebust@fys.uio.no, Suresh Jayaraman Subject: [PATCH 22/31] netvm: skb processing Date: Thu, 1 Oct 2009 19:39:01 +0530 Message-Id: <1254406141-16445-1-git-send-email-sjayaraman@suse.de> X-Mailer: git-send-email 1.6.0.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5082 Lines: 187 From: Peter Zijlstra In order to make sure emergency packets receive all memory needed to proceed ensure processing of emergency SKBs happens under PF_MEMALLOC. Use the (new) sk_backlog_rcv() wrapper to ensure this for backlog processing. Skip taps, since those are user-space again. Signed-off-by: Peter Zijlstra Signed-off-by: Suresh Jayaraman --- include/net/sock.h | 5 ++++ net/core/dev.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++----- net/core/sock.c | 16 ++++++++++++++ 3 files changed, 73 insertions(+), 5 deletions(-) Index: mmotm/include/net/sock.h =================================================================== --- mmotm.orig/include/net/sock.h +++ mmotm/include/net/sock.h @@ -619,8 +619,13 @@ static inline void sk_add_backlog(struct skb->next = NULL; } +extern int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb); + static inline int sk_backlog_rcv(struct sock *sk, struct sk_buff *skb) { + if (skb_emergency(skb)) + return __sk_backlog_rcv(sk, skb); + return sk->sk_backlog_rcv(sk, skb); } Index: mmotm/net/core/dev.c =================================================================== --- mmotm.orig/net/core/dev.c +++ mmotm/net/core/dev.c @@ -2225,6 +2225,30 @@ void netif_nit_deliver(struct sk_buff *s rcu_read_unlock(); } +/* + * Filter the protocols for which the reserves are adequate. + * + * Before adding a protocol make sure that it is either covered by the existing + * reserves, or add reserves covering the memory need of the new protocol's + * packet processing. + */ +static int skb_emergency_protocol(struct sk_buff *skb) +{ + if (skb_emergency(skb)) + switch (skb->protocol) { + case __constant_htons(ETH_P_ARP): + case __constant_htons(ETH_P_IP): + case __constant_htons(ETH_P_IPV6): + case __constant_htons(ETH_P_8021Q): + break; + + default: + return 0; + } + + return 1; +} + /** * netif_receive_skb - process receive buffer from network * @skb: buffer to process @@ -2247,13 +2271,26 @@ int netif_receive_skb(struct sk_buff *sk struct net_device *null_or_orig; int ret = NET_RX_DROP; __be16 type; + unsigned long pflags = current->flags; if (skb->vlan_tci && vlan_hwaccel_do_receive(skb)) return NET_RX_SUCCESS; + /* Emergency skb are special, they should + * - be delivered to SOCK_MEMALLOC sockets only + * - stay away from userspace + * - have bounded memory usage + * + * Use PF_MEMALLOC as a poor mans memory pool - the grouping kind. + * This saves us from propagating the allocation context down to all + * allocation sites. + */ + if (skb_emergency(skb)) + current->flags |= PF_MEMALLOC; + /* if we've gotten here through NAPI, check netpoll */ if (netpoll_receive_skb(skb)) - return NET_RX_DROP; + goto out; if (!skb->tstamp.tv64) net_timestamp(skb); @@ -2287,6 +2324,9 @@ int netif_receive_skb(struct sk_buff *sk } #endif + if (skb_emergency(skb)) + goto skip_taps; + list_for_each_entry_rcu(ptype, &ptype_all, list) { if (ptype->dev == null_or_orig || ptype->dev == skb->dev || ptype->dev == orig_dev) { @@ -2296,19 +2336,23 @@ int netif_receive_skb(struct sk_buff *sk } } +skip_taps: #ifdef CONFIG_NET_CLS_ACT skb = handle_ing(skb, &pt_prev, &ret, orig_dev); if (!skb) - goto out; + goto unlock; ncls: #endif + if (!skb_emergency_protocol(skb)) + goto drop; + skb = handle_bridge(skb, &pt_prev, &ret, orig_dev); if (!skb) - goto out; + goto unlock; skb = handle_macvlan(skb, &pt_prev, &ret, orig_dev); if (!skb) - goto out; + goto unlock; type = skb->protocol; list_for_each_entry_rcu(ptype, @@ -2325,6 +2369,7 @@ ncls: if (pt_prev) { ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev); } else { +drop: kfree_skb(skb); /* Jamal, now you will not able to escape explaining * me how you were going to use this. :-) @@ -2332,8 +2377,10 @@ ncls: ret = NET_RX_DROP; } -out: +unlock: rcu_read_unlock(); +out: + tsk_restore_flags(current, pflags, PF_MEMALLOC); return ret; } Index: mmotm/net/core/sock.c =================================================================== --- mmotm.orig/net/core/sock.c +++ mmotm/net/core/sock.c @@ -315,6 +315,22 @@ int sk_clear_memalloc(struct sock *sk) return set; } EXPORT_SYMBOL_GPL(sk_clear_memalloc); + +int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb) +{ + int ret; + unsigned long pflags = current->flags; + + /* these should have been dropped before queueing */ + BUG_ON(!sk_has_memalloc(sk)); + + current->flags |= PF_MEMALLOC; + ret = sk->sk_backlog_rcv(sk, skb); + tsk_restore_flags(current, pflags, PF_MEMALLOC); + + return ret; +} +EXPORT_SYMBOL(__sk_backlog_rcv); #endif static int sock_set_timeout(long *timeo_p, char __user *optval, int optlen) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/