linux_dsm_epyc7002/include
Hangbin Liu bd085ef678 net: add bool confirm_neigh parameter for dst_ops.update_pmtu
The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
__ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor
confirmed time.

But for tunnel code, it will call pmtu before xmit, like:
  - tnl_update_pmtu()
    - skb_dst_update_pmtu()
      - ip6_rt_update_pmtu()
        - __ip6_rt_update_pmtu()
          - dst_confirm_neigh()

If the tunnel remote dst mac address changed and we still do the neigh
confirm, we will not be able to update neigh cache and ping6 remote
will failed.

So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we
should not be invoking dst_confirm_neigh() as we have no evidence
of successful two-way communication at this point.

On the other hand it is also important to keep the neigh reachability fresh
for TCP flows, so we cannot remove this dst_confirm_neigh() call.

To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu
to choose whether we should do neigh update or not. I will add the parameter
in this patch and set all the callers to true to comply with the previous
way, and fix the tunnel code one by one on later patches.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Suggested-by: David Miller <davem@davemloft.net>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-24 22:28:54 -08:00
..
acpi
asm-generic powerpc updates for 5.5 #2 2019-12-06 13:36:31 -08:00
clocksource
crypto
drm
dt-bindings ARM: Device-tree updates 2019-12-05 12:09:47 -08:00
keys
kunit
kvm
linux Ext4 bug fixes (including a regression fix) for 5.5 2019-12-22 10:41:48 -08:00
math-emu
media
misc
net net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2019-12-24 22:28:54 -08:00
pcmcia
ras
rdma IB/core: Introduce rdma_user_mmap_entry_insert_range() API 2019-12-12 16:55:36 -05:00
scsi
soc drm msm + fixes for 5.5-rc1 2019-12-06 10:28:09 -08:00
sound ASoC: Fixes for v5.5 2019-12-17 14:18:32 +01:00
target
trace This is a relatively quiet cycle for nfsd, mainly various bugfixes. 2019-12-07 16:56:00 -08:00
uapi Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-12-22 09:54:33 -08:00
vdso
video
xen xen/interface: re-define FRONT/BACK_RING_ATTACH() 2019-12-20 13:44:42 +01:00