From: Greg Kroah-Hartman <gregkh@linuxfoundation•org>
To: linux-kernel@vger•kernel.org, netdev@vger•kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
stable@vger•kernel.org, Eric Dumazet <edumazet@google•com>,
"David S. Miller" <davem@davemloft•net>
Subject: [PATCH 4.9 65/71] net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends
Date: Tue, 16 Oct 2018 19:10:02 +0200 [thread overview]
Message-ID: <20181016170542.658704337@linuxfoundation.org> (raw)
In-Reply-To: <20181016170539.315587743@linuxfoundation.org>
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google•com>
After working on IP defragmentation lately, I found that some large
packets defeat CHECKSUM_COMPLETE optimization because of NIC adding
zero paddings on the last (small) fragment.
While removing the padding with pskb_trim_rcsum(), we set skb->ip_summed
to CHECKSUM_NONE, forcing a full csum validation, even if all prior
fragments had CHECKSUM_COMPLETE set.
We can instead compute the checksum of the part we are trimming,
usually smaller than the part we keep.
Signed-off-by: Eric Dumazet <edumazet@google•com>
Signed-off-by: David S. Miller <davem@davemloft•net>
(cherry picked from commit 88078d98d1bb085d72af8437707279e203524fa5)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation•org>
---
include/linux/skbuff.h | 5 ++---
net/core/skbuff.c | 14 ++++++++++++++
2 files changed, 16 insertions(+), 3 deletions(-)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2954,6 +2954,7 @@ static inline unsigned char *skb_push_rc
return skb->data;
}
+int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len);
/**
* pskb_trim_rcsum - trim received skb and update checksum
* @skb: buffer to trim
@@ -2967,9 +2968,7 @@ static inline int pskb_trim_rcsum(struct
{
if (likely(len >= skb->len))
return 0;
- if (skb->ip_summed == CHECKSUM_COMPLETE)
- skb->ip_summed = CHECKSUM_NONE;
- return __pskb_trim(skb, len);
+ return pskb_trim_rcsum_slow(skb, len);
}
static inline int __skb_trim_rcsum(struct sk_buff *skb, unsigned int len)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1578,6 +1578,20 @@ done:
}
EXPORT_SYMBOL(___pskb_trim);
+/* Note : use pskb_trim_rcsum() instead of calling this directly
+ */
+int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len)
+{
+ if (skb->ip_summed == CHECKSUM_COMPLETE) {
+ int delta = skb->len - len;
+
+ skb->csum = csum_sub(skb->csum,
+ skb_checksum(skb, len, delta, 0));
+ }
+ return __pskb_trim(skb, len);
+}
+EXPORT_SYMBOL(pskb_trim_rcsum_slow);
+
/**
* __pskb_pull_tail - advance tail of skb header
* @skb: buffer to reallocate
next prev parent reply other threads:[~2018-10-16 17:10 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20181016170539.315587743@linuxfoundation.org>
2018-10-16 17:09 ` [PATCH 4.9 43/71] inet: frags: change inet_frags_init_net() return value Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 44/71] inet: frags: add a pointer to struct netns_frags Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 45/71] inet: frags: refactor ipfrag_init() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 46/71] inet: frags: refactor ipv6_frag_init() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 47/71] inet: frags: refactor lowpan_net_frag_init() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 48/71] ipv6: export ip6 fragments sysctl to unprivileged users Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 49/71] rhashtable: add schedule points Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 50/71] inet: frags: use rhashtables for reassembly units Greg Kroah-Hartman
2018-10-26 13:39 ` Stefan Schmidt
2018-11-29 12:54 ` Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 51/71] inet: frags: remove some helpers Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 52/71] inet: frags: get rif of inet_frag_evicting() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 53/71] inet: frags: remove inet_frag_maybe_warn_overflow() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 54/71] inet: frags: break the 2GB limit for frags storage Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 55/71] inet: frags: do not clone skb in ip_expire() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 56/71] ipv6: frags: rewrite ip6_expire_frag_queue() Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 57/71] rhashtable: reorganize struct rhashtable layout Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 58/71] inet: frags: reorganize struct netns_frags Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 59/71] inet: frags: get rid of ipfrag_skb_cb/FRAG_CB Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 60/71] inet: frags: fix ip6frag_low_thresh boundary Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 61/71] ip: discard IPv4 datagrams with overlapping segments Greg Kroah-Hartman
2018-10-16 17:09 ` [PATCH 4.9 62/71] net: speed up skb_rbtree_purge() Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 63/71] net: modify skb_rbtree_purge to return the truesize of all purged skbs Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 64/71] ipv6: defrag: drop non-last frags smaller than min mtu Greg Kroah-Hartman
2018-10-16 17:10 ` Greg Kroah-Hartman [this message]
2018-10-16 17:10 ` [PATCH 4.9 66/71] net: add rb_to_skb() and other rb tree helpers Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 67/71] ip: use rb trees for IP frag queue Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 68/71] ip: add helpers to process in-order fragments faster Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 69/71] ip: process in-order fragments efficiently Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 70/71] ip: frags: fix crash in ip_do_fragment() Greg Kroah-Hartman
2018-10-16 17:10 ` [PATCH 4.9 71/71] ipv4: frags: precedence bug in ip_expire() Greg Kroah-Hartman
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