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    • Hannes Frederic Sowa's avatar
      ipv6: fix compiler warning in ipv6_exthdrs_len · f52d81dc
      Hannes Frederic Sowa authored 
      Commit 299603e8

 ("net-gro: Prepare GRO
stack for the upcoming tunneling support") used an uninitialized variable
which leads to the following compiler warning:

net/ipv6/ip6_offload.c: In function ‘ipv6_gro_complete’:
net/ipv6/ip6_offload.c:178:24: warning: ‘optlen’ may be used uninitialized in this function [-Wmaybe-uninitialized]
    opth = (void *)opth + optlen;
                        ^
net/ipv6/ip6_offload.c:164:22: note: ‘optlen’ was declared here
  int len = 0, proto, optlen;
                      ^
Fix it up.

Cc: Jerry Chu <hkchu@google.com>
Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f52d81dc
    • David S. Miller's avatar
      Merge branch 'bonding_rcu' · df012169
      David S. Miller authored 
      

Ding Tianhong says:

====================
bonding: rebuild the lock use for bond monitor

Now the bond slave list is not protected by bond lock, only by RTNL,
but the monitor still use the bond lock to protect the slave list,
it is useless, according to the Veaceslav's opinion, there were
three way to fix the protect problem:

1. add bond_master_upper_dev_link() and bond_upper_dev_unlink()
   in bond->lock, but it is unsafe to call call_netdevice_notifiers()
   in write lock.
2. remove unused bond->lock for monitor function, only use the exist
   rtnl lock(), it will take performance loss in fast path.
3. use RCU to protect the slave list, of course, performance is better,
   but in slow path, it is ignored.

obviously the solution 1 is not fit here, I will consider the 2 and 3
solution. My principle is simple, if in fast path, RCU is better,
otherwise in slow path, both is well, but according to the Jay Vosburgh's
opinion, the monitor will loss performace if use RTNL to protect the all
slave list, so remove the bond lock and replace with RCU.

The second problem is the curr_slave_lock for bond, it is too old and
unwanted in many place, because the curr_active_slave would only be
changed in 3 place:

1. enslave slave.
2. release slave.
3. change active slave.

all above were already holding bond lock, RTNL and curr_slave_lock
together, it is tedious and no need to add so mach lock, when change
the curr_active_slave, you have to hold the RTNL and curr_slave_lock
together, and when you read the curr_active_slave, RTNL or curr_slave_lock,
any one of them is no problem.

for the stability, I did not change the logic for the monitor,
all change is clear and simple, I have test the patch set for lockdep,
it work well and stability.

v2. accept the Jay Vosburgh's opinion, remove the RTNL and replace with RCU,
    also add some rcu function for bond use, so the patch set reach 10.

v3. accept the Nikolay Aleksandrov's opinion, remove no needed bond_has_slave_rcu(),
    add protection for several 3ad mode handler functions and current_arp_slave.
    rebuild the bond_first_slave_rcu(), make it more clear.

v4. because the struct netdev_adjacent should not be exist in netdevice.h, so I have
    to make a new function to support micro bond_first_slave_rcu().
    also add a new patch to simplify the bond_resend_igmp_join_requests_delayed().

v5. according the Jay Vosburgh's opinion, in patch 2 and 6, the calling of notify
    peer is hardly to happen with the bond_xxx_commit() when the monitoring is running,
    so the performance impact about make two round trips to one trip on RTNL is minimal,
    no need to do that,the reason is very clear, so modify the patch 2 and 6, recover
    the notify peer in RTNL alone.
====================

Signed-off-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      df012169
    • dingtianhong's avatar
      bonding: rebuild the bond_resend_igmp_join_requests_delayed() · f2369109
      dingtianhong authored 
      

The bond_resend_igmp_join_requests_delayed() and
bond_resend_igmp_join_requests() should be integrated,
because the bond_resend_igmp_join_requests_delayed() did
nothing except bond_resend_igmp_join_requests().

The bond igmp_retrans could only be changed in bond_change_active_slave
and here, bond_change_active_slave will be called in RTNL and curr_slave_lock,
the bond_resend_igmp_join_requests already hold RTNL, so no need
to free RTNL and hold curr_slave_lock again, it may be a small optimization,
so move the igmp_retrans in RTNL and remove the curr_slave_lock.

Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f2369109
    • dingtianhong's avatar
      bonding: remove unwanted lock for bond_store_primaryxxx() · 75ad932c
      dingtianhong authored 
      

The bond_select_active_slave() will not release and acquire
bond lock, so it is no need to read the bond lock for them,
and the bond_store_primaryxxx() is already in RTNL, so remove the
unwanted lock.

Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      75ad932c
    • dingtianhong's avatar
      bonding: remove unwanted lock for bond_option_active_slave_set() · 4e789fc1
      dingtianhong authored 
      

The bond_option_active_slave_set() is always called in RTNL,
the RTNL could protect bond slave list, so remove the unwanted
bond lock.

Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4e789fc1
    • dingtianhong's avatar
      bonding: add RCU for bond_3ad_state_machine_handler() · be79bd04
      dingtianhong authored 
      

The bond_3ad_state_machine_handler() use the bond lock to protect
the bond slave list and slave port together, but it is not enough,
the bond slave list was link and unlink in RTNL, not bond lock,
so I add RCU to protect the slave list from leaving.

The bond lock is still used here, because when the slave has been
removed from the list by the time the state machine runs, it appears
to be possible for both function to manupulate the same aggregator->lag_ports
by finding the aggregator via two different ports that are both members of
that aggregator (i.e., port A of the agg is being unbound, and port B
of the agg is runing its state machine).

If I remove the bond lock, there are nothing to mutex changes
to aggregator->lag_ports between bond_3ad_state_machine_handler and
bond_3ad_unbind_slave, So the bond lock is the simplest way to protect
aggregator->lag_ports.

There was a lot of function need RCU protect, I have two choice
to make the function in RCU-safe, (1) create new similar functions
and make the bond slave list in RCU. (2) modify the existed functions
and make them in read-side critical section, because the RCU
read-side critical sections may be nested.

I choose (2) because it is no need to create more similar functions.

The nots in the function is still too old, clean up the nots.

Suggested-by: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      be79bd04
    • dingtianhong's avatar
      bonding: remove unwanted lock for bond enslave and release · c8517035
      dingtianhong authored 
      

The bond_change_active_slave() and bond_select_active_slave()
do't need bond lock anymore, so remove the unwanted bond lock
for these two functions.

The bond_select_active_slave() will release and acquire
curr_slave_lock, so the curr_slave_lock need to protect
the function.

In bond enslave and bond release, the bond slave list is also
protected by RTNL, so bond lock is no need to exist, remove
the lock and clean the functions.

Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c8517035
    • dingtianhong's avatar
      bonding: rebuild the lock use for bond_activebackup_arp_mon() · eb9fa4b0
      dingtianhong authored 
      

The bond_activebackup_arp_mon() use the bond lock for read to
protect the slave list, it is no effect, and the RTNL is only
called for bond_ab_arp_commit() and peer notify, for the performance
better, use RCU to replace with the bond lock, to the bond slave
list need to called in RCU, add a new bond_first_slave_rcu()
to get the first slave in RCU protection.

In bond_ab_arp_probe(), the bond->current_arp_slave may changd
if bond release slave, just like:

        bond_ab_arp_probe()                     bond_release()
        cpu 0                                   cpu 1
        ...
        if (bond->current_arp_slave...)         ...
        ...                             bond->current_arp_slave = NULl
        bond->current_arp_slave->dev->name      ...

So the current_arp_slave need to dereference in the section.

Suggested-by: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      eb9fa4b0
    • dingtianhong's avatar
      bonding: create bond_first_slave_rcu() · e001bfad
      dingtianhong authored 
      

The bond_first_slave_rcu() will be used to instead of bond_first_slave()
in rcu_read_lock().

According to the Jay Vosburgh's suggestion, the struct netdev_adjacent
should hide from users who wanted to use it directly. so I package a
new function to get the first slave of the bond.

Suggested-by: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e001bfad
    • dingtianhong's avatar
      bonding: rebuild the lock use for bond_loadbalance_arp_mon() · 2e52f4fe
      dingtianhong authored 
      

The bond_loadbalance_arp_mon() use the bond lock to protect the
bond slave list, it is no effect, so I could use RTNL or RCU to
replace it, considering the performance impact, the RCU is more
better here, so the bond lock replace with the RCU.

The bond_select_active_slave() need RTNL and curr_slave_lock
together, but there is no RTNL lock here, so add a rtnl_rtylock.

Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2e52f4fe
    • dingtianhong's avatar
      bonding: rebuild the lock use for bond_alb_monitor() · 733ab639
      dingtianhong authored 
      

The bond_alb_monitor use bond lock to protect the bond slave list,
it is no effect here, we need to use RTNL or RCU to replace bond lock,
the bond_alb_monitor will called 10 times one second, RTNL may loss
performance here, so I replace bond lock with RCU to protect the
bond slave list, also the RTNL is preserved, the logic of the monitor
did not changed.

Suggested-by: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      733ab639
    • dingtianhong's avatar
      bonding: rebuild the lock use for bond_mii_monitor() · 4cb4f97b
      dingtianhong authored 
      

The bond_mii_monitor() still use bond lock to protect bond slave list,
it is no effect, I have 2 way to fix the problem, move the RTNL to the
top of the function, or add RCU to protect the bond slave list,
according to the Jay Vosburgh's opinion, 10 times one second is a
truely big performance loss if use RTNL to protect the whole monitor,
so I would take the advice and use RCU to protect the bond slave list.

The bond_has_slave() will not protect by anything, there will no things
happen if the slave list is be changed, unless the bond was free, but
it will not happened before the monitor, the bond will closed before
be freed.

The peers notify for the bond will calling curr_active_slave, so
derefence the slave to make sure we will accessing the same slave
if the curr_active_slave changed, as the rcu dereference need in
read-side critical sector and bond_change_active_slave() will call
it with no RCU hold,  so add peer notify in rcu_read_lock which
will be nested in monitor.

Suggested-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Suggested-by: default avatarVeaceslav Falico <vfalico@redhat.com>
Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4cb4f97b