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Xin Long 8aec4959d8 ip6_gre: update dst pmtu if dev mtu has been updated by toobig in __gre6_xmit
When receiving a Toobig icmpv6 packet, ip6gre_err would just set
tunnel dev's mtu, that's not enough. For skb_dst(skb)'s pmtu may
still be using the old value, it has no chance to be updated with
tunnel dev's mtu.

Jianlin found this issue by reducing route's mtu while running
netperf, the performance went to 0.

ip6ip6 and ip4ip6 tunnel can work well with this, as they lookup
the upper dst and update_pmtu it's pmtu or icmpv6_send a Toobig
to upper socket after setting tunnel dev's mtu.

We couldn't do that for ip6_gre, as gre's inner packet could be
any protocol, it's difficult to handle them (like lookup upper
dst) in a good way.

So this patch is to fix it by updating skb_dst(skb)'s pmtu when
dev->mtu < skb_dst(skb)'s pmtu in tx path. It's safe to do this
update there, as usually dev->mtu <= skb_dst(skb)'s pmtu and no
performance regression can be caused by this.

Fixes: c12b395a46 ("gre: Support GRE over IPv6")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-27 23:45:42 +09:00
arch Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-10-20 18:20:17 -04:00
block bio_copy_user_iov(): don't ignore ->iov_offset 2017-10-10 23:55:14 -04:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto Merge commit 'tags/keys-fixes-20171018' into fixes-v4.14-rc5 2017-10-19 12:28:38 +11:00
Documentation doc: Fix RCU's docbook options 2017-10-19 22:26:11 -04:00
drivers net: stmmac: First Queue must always be in DCB mode 2017-10-27 23:32:56 +09:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-10-21 21:39:18 -04:00
include Merge tag 'mlx5-fixes-2017-10-26' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux 2017-10-27 22:23:41 +09:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc fix a typo in put_compat_shm_info() 2017-09-25 20:41:46 -04:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
net ip6_gre: update dst pmtu if dev mtu has been updated by toobig in __gre6_xmit 2017-10-27 23:45:42 +09:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
scripts Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2017-10-21 21:46:39 -04:00
security commoncap: move assignment of fs_ns to avoid null pointer dereference 2017-10-19 13:09:33 +11:00
sound ALSA: hda - Fix incorrect TLV callback check introduced during set_fs() removal 2017-10-18 12:27:00 +02:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-21 22:44:48 -04:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap Update James Hogan's email address 2017-10-04 17:11:53 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Another latent bug related to PCID, an out-of-bounds access, 2017-10-12 10:42:03 -07:00
Makefile Linux 4.14-rc5 2017-10-15 21:01:12 -04:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.