<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/net/core, branch v3.4.108</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>net: use for_each_netdev_safe() in rtnl_group_changelink()</title>
<updated>2015-06-19T03:40:30+00:00</updated>
<author>
<name>WANG Cong</name>
<email>xiyou.wangcong@gmail.com</email>
</author>
<published>2015-03-23T23:31:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f10c969c1fd328323f45ac953c992b756b25f31b'/>
<id>f10c969c1fd328323f45ac953c992b756b25f31b</id>
<content type='text'>
commit d079535d5e1bf5e2e7c856bae2483414ea21e137 upstream.

In case we move the whole dev group to another netns,
we should call for_each_netdev_safe(), otherwise we get
a soft lockup:

 NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [ip:798]
 irq event stamp: 255424
 hardirqs last  enabled at (255423): [&lt;ffffffff81a2aa95&gt;] restore_args+0x0/0x30
 hardirqs last disabled at (255424): [&lt;ffffffff81a2ad5a&gt;] apic_timer_interrupt+0x6a/0x80
 softirqs last  enabled at (255422): [&lt;ffffffff81079ebc&gt;] __do_softirq+0x2c1/0x3a9
 softirqs last disabled at (255417): [&lt;ffffffff8107a190&gt;] irq_exit+0x41/0x95
 CPU: 0 PID: 798 Comm: ip Not tainted 4.0.0-rc4+ #881
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 task: ffff8800d1b88000 ti: ffff880119530000 task.ti: ffff880119530000
 RIP: 0010:[&lt;ffffffff810cad11&gt;]  [&lt;ffffffff810cad11&gt;] debug_lockdep_rcu_enabled+0x28/0x30
 RSP: 0018:ffff880119533778  EFLAGS: 00000246
 RAX: ffff8800d1b88000 RBX: 0000000000000002 RCX: 0000000000000038
 RDX: 0000000000000000 RSI: ffff8800d1b888c8 RDI: ffff8800d1b888c8
 RBP: ffff880119533778 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 000000000000b5c2 R12: 0000000000000246
 R13: ffff880119533708 R14: 00000000001d5a40 R15: ffff88011a7d5a40
 FS:  00007fc01315f740(0000) GS:ffff88011a600000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 00007f367a120988 CR3: 000000011849c000 CR4: 00000000000007f0
 Stack:
  ffff880119533798 ffffffff811ac868 ffffffff811ac831 ffffffff811ac828
  ffff8801195337c8 ffffffff811ac8c9 ffff8801195339b0 ffff8801197633e0
  0000000000000000 ffff8801195339b0 ffff8801195337d8 ffffffff811ad2d7
 Call Trace:
  [&lt;ffffffff811ac868&gt;] rcu_read_lock+0x37/0x6e
  [&lt;ffffffff811ac831&gt;] ? rcu_read_unlock+0x5f/0x5f
  [&lt;ffffffff811ac828&gt;] ? rcu_read_unlock+0x56/0x5f
  [&lt;ffffffff811ac8c9&gt;] __fget+0x2a/0x7a
  [&lt;ffffffff811ad2d7&gt;] fget+0x13/0x15
  [&lt;ffffffff811be732&gt;] proc_ns_fget+0xe/0x38
  [&lt;ffffffff817c7714&gt;] get_net_ns_by_fd+0x11/0x59
  [&lt;ffffffff817df359&gt;] rtnl_link_get_net+0x33/0x3e
  [&lt;ffffffff817df3d7&gt;] do_setlink+0x73/0x87b
  [&lt;ffffffff810b28ce&gt;] ? trace_hardirqs_off+0xd/0xf
  [&lt;ffffffff81a2aa95&gt;] ? retint_restore_args+0xe/0xe
  [&lt;ffffffff817e0301&gt;] rtnl_newlink+0x40c/0x699
  [&lt;ffffffff817dffe0&gt;] ? rtnl_newlink+0xeb/0x699
  [&lt;ffffffff81a29246&gt;] ? _raw_spin_unlock+0x28/0x33
  [&lt;ffffffff8143ed1e&gt;] ? security_capable+0x18/0x1a
  [&lt;ffffffff8107da51&gt;] ? ns_capable+0x4d/0x65
  [&lt;ffffffff817de5ce&gt;] rtnetlink_rcv_msg+0x181/0x194
  [&lt;ffffffff817de407&gt;] ? rtnl_lock+0x17/0x19
  [&lt;ffffffff817de407&gt;] ? rtnl_lock+0x17/0x19
  [&lt;ffffffff817de44d&gt;] ? __rtnl_unlock+0x17/0x17
  [&lt;ffffffff818327c6&gt;] netlink_rcv_skb+0x4d/0x93
  [&lt;ffffffff817de42f&gt;] rtnetlink_rcv+0x26/0x2d
  [&lt;ffffffff81830f18&gt;] netlink_unicast+0xcb/0x150
  [&lt;ffffffff8183198e&gt;] netlink_sendmsg+0x501/0x523
  [&lt;ffffffff8115cba9&gt;] ? might_fault+0x59/0xa9
  [&lt;ffffffff817b5398&gt;] ? copy_from_user+0x2a/0x2c
  [&lt;ffffffff817b7b74&gt;] sock_sendmsg+0x34/0x3c
  [&lt;ffffffff817b7f6d&gt;] ___sys_sendmsg+0x1b8/0x255
  [&lt;ffffffff8115c5eb&gt;] ? handle_pte_fault+0xbd5/0xd4a
  [&lt;ffffffff8100a2b0&gt;] ? native_sched_clock+0x35/0x37
  [&lt;ffffffff8109e94b&gt;] ? sched_clock_local+0x12/0x72
  [&lt;ffffffff8109eb9c&gt;] ? sched_clock_cpu+0x9e/0xb7
  [&lt;ffffffff810cadbf&gt;] ? rcu_read_lock_held+0x3b/0x3d
  [&lt;ffffffff811ac1d8&gt;] ? __fcheck_files+0x4c/0x58
  [&lt;ffffffff811ac946&gt;] ? __fget_light+0x2d/0x52
  [&lt;ffffffff817b8adc&gt;] __sys_sendmsg+0x42/0x60
  [&lt;ffffffff817b8b0c&gt;] SyS_sendmsg+0x12/0x1c
  [&lt;ffffffff81a29e32&gt;] system_call_fastpath+0x12/0x17

Fixes: e7ed828f10bd8 ("netlink: support setting devgroup parameters")
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Zefan Li &lt;lizefan@huawei.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit d079535d5e1bf5e2e7c856bae2483414ea21e137 upstream.

In case we move the whole dev group to another netns,
we should call for_each_netdev_safe(), otherwise we get
a soft lockup:

 NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [ip:798]
 irq event stamp: 255424
 hardirqs last  enabled at (255423): [&lt;ffffffff81a2aa95&gt;] restore_args+0x0/0x30
 hardirqs last disabled at (255424): [&lt;ffffffff81a2ad5a&gt;] apic_timer_interrupt+0x6a/0x80
 softirqs last  enabled at (255422): [&lt;ffffffff81079ebc&gt;] __do_softirq+0x2c1/0x3a9
 softirqs last disabled at (255417): [&lt;ffffffff8107a190&gt;] irq_exit+0x41/0x95
 CPU: 0 PID: 798 Comm: ip Not tainted 4.0.0-rc4+ #881
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 task: ffff8800d1b88000 ti: ffff880119530000 task.ti: ffff880119530000
 RIP: 0010:[&lt;ffffffff810cad11&gt;]  [&lt;ffffffff810cad11&gt;] debug_lockdep_rcu_enabled+0x28/0x30
 RSP: 0018:ffff880119533778  EFLAGS: 00000246
 RAX: ffff8800d1b88000 RBX: 0000000000000002 RCX: 0000000000000038
 RDX: 0000000000000000 RSI: ffff8800d1b888c8 RDI: ffff8800d1b888c8
 RBP: ffff880119533778 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 000000000000b5c2 R12: 0000000000000246
 R13: ffff880119533708 R14: 00000000001d5a40 R15: ffff88011a7d5a40
 FS:  00007fc01315f740(0000) GS:ffff88011a600000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 00007f367a120988 CR3: 000000011849c000 CR4: 00000000000007f0
 Stack:
  ffff880119533798 ffffffff811ac868 ffffffff811ac831 ffffffff811ac828
  ffff8801195337c8 ffffffff811ac8c9 ffff8801195339b0 ffff8801197633e0
  0000000000000000 ffff8801195339b0 ffff8801195337d8 ffffffff811ad2d7
 Call Trace:
  [&lt;ffffffff811ac868&gt;] rcu_read_lock+0x37/0x6e
  [&lt;ffffffff811ac831&gt;] ? rcu_read_unlock+0x5f/0x5f
  [&lt;ffffffff811ac828&gt;] ? rcu_read_unlock+0x56/0x5f
  [&lt;ffffffff811ac8c9&gt;] __fget+0x2a/0x7a
  [&lt;ffffffff811ad2d7&gt;] fget+0x13/0x15
  [&lt;ffffffff811be732&gt;] proc_ns_fget+0xe/0x38
  [&lt;ffffffff817c7714&gt;] get_net_ns_by_fd+0x11/0x59
  [&lt;ffffffff817df359&gt;] rtnl_link_get_net+0x33/0x3e
  [&lt;ffffffff817df3d7&gt;] do_setlink+0x73/0x87b
  [&lt;ffffffff810b28ce&gt;] ? trace_hardirqs_off+0xd/0xf
  [&lt;ffffffff81a2aa95&gt;] ? retint_restore_args+0xe/0xe
  [&lt;ffffffff817e0301&gt;] rtnl_newlink+0x40c/0x699
  [&lt;ffffffff817dffe0&gt;] ? rtnl_newlink+0xeb/0x699
  [&lt;ffffffff81a29246&gt;] ? _raw_spin_unlock+0x28/0x33
  [&lt;ffffffff8143ed1e&gt;] ? security_capable+0x18/0x1a
  [&lt;ffffffff8107da51&gt;] ? ns_capable+0x4d/0x65
  [&lt;ffffffff817de5ce&gt;] rtnetlink_rcv_msg+0x181/0x194
  [&lt;ffffffff817de407&gt;] ? rtnl_lock+0x17/0x19
  [&lt;ffffffff817de407&gt;] ? rtnl_lock+0x17/0x19
  [&lt;ffffffff817de44d&gt;] ? __rtnl_unlock+0x17/0x17
  [&lt;ffffffff818327c6&gt;] netlink_rcv_skb+0x4d/0x93
  [&lt;ffffffff817de42f&gt;] rtnetlink_rcv+0x26/0x2d
  [&lt;ffffffff81830f18&gt;] netlink_unicast+0xcb/0x150
  [&lt;ffffffff8183198e&gt;] netlink_sendmsg+0x501/0x523
  [&lt;ffffffff8115cba9&gt;] ? might_fault+0x59/0xa9
  [&lt;ffffffff817b5398&gt;] ? copy_from_user+0x2a/0x2c
  [&lt;ffffffff817b7b74&gt;] sock_sendmsg+0x34/0x3c
  [&lt;ffffffff817b7f6d&gt;] ___sys_sendmsg+0x1b8/0x255
  [&lt;ffffffff8115c5eb&gt;] ? handle_pte_fault+0xbd5/0xd4a
  [&lt;ffffffff8100a2b0&gt;] ? native_sched_clock+0x35/0x37
  [&lt;ffffffff8109e94b&gt;] ? sched_clock_local+0x12/0x72
  [&lt;ffffffff8109eb9c&gt;] ? sched_clock_cpu+0x9e/0xb7
  [&lt;ffffffff810cadbf&gt;] ? rcu_read_lock_held+0x3b/0x3d
  [&lt;ffffffff811ac1d8&gt;] ? __fcheck_files+0x4c/0x58
  [&lt;ffffffff811ac946&gt;] ? __fget_light+0x2d/0x52
  [&lt;ffffffff817b8adc&gt;] __sys_sendmsg+0x42/0x60
  [&lt;ffffffff817b8b0c&gt;] SyS_sendmsg+0x12/0x1c
  [&lt;ffffffff81a29e32&gt;] system_call_fastpath+0x12/0x17

Fixes: e7ed828f10bd8 ("netlink: support setting devgroup parameters")
Signed-off-by: Cong Wang &lt;xiyou.wangcong@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Zefan Li &lt;lizefan@huawei.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rtnetlink: ifla_vf_policy: fix misuses of NLA_BINARY</title>
<updated>2015-06-19T03:40:14+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2015-02-05T17:44:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1f18b8072286b6fea3d5d2ac938d7631586b14c6'/>
<id>1f18b8072286b6fea3d5d2ac938d7631586b14c6</id>
<content type='text'>
commit 364d5716a7adb91b731a35765d369602d68d2881 upstream.

ifla_vf_policy[] is wrong in advertising its individual member types as
NLA_BINARY since .type = NLA_BINARY in combination with .len declares the
len member as *max* attribute length [0, len].

The issue is that when do_setvfinfo() is being called to set up a VF
through ndo handler, we could set corrupted data if the attribute length
is less than the size of the related structure itself.

The intent is exactly the opposite, namely to make sure to pass at least
data of minimum size of len.

Fixes: ebc08a6f47ee ("rtnetlink: Add VF config code to rtnetlink")
Cc: Mitch Williams &lt;mitch.a.williams@intel.com&gt;
Cc: Jeff Kirsher &lt;jeffrey.t.kirsher@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Thomas Graf &lt;tgraf@suug.ch&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[lizf: Backported to 3.4: drop changes to IFLA_VF_RATE and IFLA_VF_LINK_STATE]
Signed-off-by: Zefan Li &lt;lizefan@huawei.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 364d5716a7adb91b731a35765d369602d68d2881 upstream.

ifla_vf_policy[] is wrong in advertising its individual member types as
NLA_BINARY since .type = NLA_BINARY in combination with .len declares the
len member as *max* attribute length [0, len].

The issue is that when do_setvfinfo() is being called to set up a VF
through ndo handler, we could set corrupted data if the attribute length
is less than the size of the related structure itself.

The intent is exactly the opposite, namely to make sure to pass at least
data of minimum size of len.

Fixes: ebc08a6f47ee ("rtnetlink: Add VF config code to rtnetlink")
Cc: Mitch Williams &lt;mitch.a.williams@intel.com&gt;
Cc: Jeff Kirsher &lt;jeffrey.t.kirsher@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Thomas Graf &lt;tgraf@suug.ch&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[lizf: Backported to 3.4: drop changes to IFLA_VF_RATE and IFLA_VF_LINK_STATE]
Signed-off-by: Zefan Li &lt;lizefan@huawei.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: Fix stacked vlan offload features computation</title>
<updated>2015-04-14T09:33:48+00:00</updated>
<author>
<name>Toshiaki Makita</name>
<email>makita.toshiaki@lab.ntt.co.jp</email>
</author>
<published>2014-12-22T10:04:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3f2bfecbcd11c03e3a0303c99097981edc386cb9'/>
<id>3f2bfecbcd11c03e3a0303c99097981edc386cb9</id>
<content type='text'>
commit 796f2da81bead71ffc91ef70912cd8d1827bf756 upstream.

When vlan tags are stacked, it is very likely that the outer tag is stored
in skb-&gt;vlan_tci and skb-&gt;protocol shows the inner tag's vlan_proto.
Currently netif_skb_features() first looks at skb-&gt;protocol even if there
is the outer tag in vlan_tci, thus it incorrectly retrieves the protocol
encapsulated by the inner vlan instead of the inner vlan protocol.
This allows GSO packets to be passed to HW and they end up being
corrupted.

Fixes: 58e998c6d239 ("offloading: Force software GSO for multiple vlan tags.")
Signed-off-by: Toshiaki Makita &lt;makita.toshiaki@lab.ntt.co.jp&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[lizf: Backported to 3.4:
 - remove ETH_P_8021AD
 - pass protocol to harmonize_features()]
Signed-off-by: Zefan Li &lt;lizefan@huawei.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 796f2da81bead71ffc91ef70912cd8d1827bf756 upstream.

When vlan tags are stacked, it is very likely that the outer tag is stored
in skb-&gt;vlan_tci and skb-&gt;protocol shows the inner tag's vlan_proto.
Currently netif_skb_features() first looks at skb-&gt;protocol even if there
is the outer tag in vlan_tci, thus it incorrectly retrieves the protocol
encapsulated by the inner vlan instead of the inner vlan protocol.
This allows GSO packets to be passed to HW and they end up being
corrupted.

Fixes: 58e998c6d239 ("offloading: Force software GSO for multiple vlan tags.")
Signed-off-by: Toshiaki Makita &lt;makita.toshiaki@lab.ntt.co.jp&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[lizf: Backported to 3.4:
 - remove ETH_P_8021AD
 - pass protocol to harmonize_features()]
Signed-off-by: Zefan Li &lt;lizefan@huawei.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: Do not enable tx-nocache-copy by default</title>
<updated>2014-12-01T10:02:45+00:00</updated>
<author>
<name>Benjamin Poirier</name>
<email>bpoirier@suse.de</email>
</author>
<published>2014-01-07T15:11:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=10d5d534765ccd203e34e3ccf5f67edba5e577c7'/>
<id>10d5d534765ccd203e34e3ccf5f67edba5e577c7</id>
<content type='text'>
commit cdb3f4a31b64c3a1c6eef40bc01ebc9594c58a8c upstream.

There are many cases where this feature does not improve performance or even
reduces it.

For example, here are the results from tests that I've run using 3.12.6 on one
Intel Xeon W3565 and one i7 920 connected by ixgbe adapters. The results are
from the Xeon, but they're similar on the i7. All numbers report the
mean±stddev over 10 runs of 10s.

1) latency tests similar to what is described in "c6e1a0d net: Allow no-cache
copy from user on transmit"
There is no statistically significant difference between tx-nocache-copy
on/off.
nic irqs spread out (one queue per cpu)

200x netperf -r 1400,1
tx-nocache-copy off
        692000±1000 tps
        50/90/95/99% latency (us): 275±2/643.8±0.4/799±1/2474.4±0.3
tx-nocache-copy on
        693000±1000 tps
        50/90/95/99% latency (us): 274±1/644.1±0.7/800±2/2474.5±0.7

200x netperf -r 14000,14000
tx-nocache-copy off
        86450±80 tps
        50/90/95/99% latency (us): 334.37±0.02/838±1/2100±20/3990±40
tx-nocache-copy on
        86110±60 tps
        50/90/95/99% latency (us): 334.28±0.01/837±2/2110±20/3990±20

2) single stream throughput tests
tx-nocache-copy leads to higher service demand

                        throughput  cpu0        cpu1        demand
                        (Gb/s)      (Gcycle)    (Gcycle)    (cycle/B)

nic irqs and netperf on cpu0 (1x netperf -T0,0 -t omni -- -d send)

tx-nocache-copy off     9402±5      9.4±0.2                 0.80±0.01
tx-nocache-copy on      9403±3      9.85±0.04               0.838±0.004

nic irqs on cpu0, netperf on cpu1 (1x netperf -T1,1 -t omni -- -d send)

tx-nocache-copy off     9401±5      5.83±0.03   5.0±0.1     0.923±0.007
tx-nocache-copy on      9404±2      5.74±0.03   5.523±0.009 0.958±0.002

As a second example, here are some results from Eric Dumazet with latest
net-next.
tx-nocache-copy also leads to higher service demand

(cpu is Intel(R) Xeon(R) CPU X5660  @ 2.80GHz)

lpq83:~# ./ethtool -K eth0 tx-nocache-copy on
lpq83:~# perf stat ./netperf -H lpq84 -c
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to lpq84.prod.google.com () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  16384    10.00      9407.44   2.50     -1.00    0.522   -1.000

 Performance counter stats for './netperf -H lpq84 -c':

       4282.648396 task-clock                #    0.423 CPUs utilized
             9,348 context-switches          #    0.002 M/sec
                88 CPU-migrations            #    0.021 K/sec
               355 page-faults               #    0.083 K/sec
    11,812,797,651 cycles                    #    2.758 GHz                     [82.79%]
     9,020,522,817 stalled-cycles-frontend   #   76.36% frontend cycles idle    [82.54%]
     4,579,889,681 stalled-cycles-backend    #   38.77% backend  cycles idle    [67.33%]
     6,053,172,792 instructions              #    0.51  insns per cycle
                                             #    1.49  stalled cycles per insn [83.64%]
       597,275,583 branches                  #  139.464 M/sec                   [83.70%]
         8,960,541 branch-misses             #    1.50% of all branches         [83.65%]

      10.128990264 seconds time elapsed

lpq83:~# ./ethtool -K eth0 tx-nocache-copy off
lpq83:~# perf stat ./netperf -H lpq84 -c
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to lpq84.prod.google.com () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  16384    10.00      9412.45   2.15     -1.00    0.449   -1.000

 Performance counter stats for './netperf -H lpq84 -c':

       2847.375441 task-clock                #    0.281 CPUs utilized
            11,632 context-switches          #    0.004 M/sec
                49 CPU-migrations            #    0.017 K/sec
               354 page-faults               #    0.124 K/sec
     7,646,889,749 cycles                    #    2.686 GHz                     [83.34%]
     6,115,050,032 stalled-cycles-frontend   #   79.97% frontend cycles idle    [83.31%]
     1,726,460,071 stalled-cycles-backend    #   22.58% backend  cycles idle    [66.55%]
     2,079,702,453 instructions              #    0.27  insns per cycle
                                             #    2.94  stalled cycles per insn [83.22%]
       363,773,213 branches                  #  127.757 M/sec                   [83.29%]
         4,242,732 branch-misses             #    1.17% of all branches         [83.51%]

      10.128449949 seconds time elapsed

CC: Tom Herbert &lt;therbert@google.com&gt;
Signed-off-by: Benjamin Poirier &lt;bpoirier@suse.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Zefan Li &lt;lizefan@huawei.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cdb3f4a31b64c3a1c6eef40bc01ebc9594c58a8c upstream.

There are many cases where this feature does not improve performance or even
reduces it.

For example, here are the results from tests that I've run using 3.12.6 on one
Intel Xeon W3565 and one i7 920 connected by ixgbe adapters. The results are
from the Xeon, but they're similar on the i7. All numbers report the
mean±stddev over 10 runs of 10s.

1) latency tests similar to what is described in "c6e1a0d net: Allow no-cache
copy from user on transmit"
There is no statistically significant difference between tx-nocache-copy
on/off.
nic irqs spread out (one queue per cpu)

200x netperf -r 1400,1
tx-nocache-copy off
        692000±1000 tps
        50/90/95/99% latency (us): 275±2/643.8±0.4/799±1/2474.4±0.3
tx-nocache-copy on
        693000±1000 tps
        50/90/95/99% latency (us): 274±1/644.1±0.7/800±2/2474.5±0.7

200x netperf -r 14000,14000
tx-nocache-copy off
        86450±80 tps
        50/90/95/99% latency (us): 334.37±0.02/838±1/2100±20/3990±40
tx-nocache-copy on
        86110±60 tps
        50/90/95/99% latency (us): 334.28±0.01/837±2/2110±20/3990±20

2) single stream throughput tests
tx-nocache-copy leads to higher service demand

                        throughput  cpu0        cpu1        demand
                        (Gb/s)      (Gcycle)    (Gcycle)    (cycle/B)

nic irqs and netperf on cpu0 (1x netperf -T0,0 -t omni -- -d send)

tx-nocache-copy off     9402±5      9.4±0.2                 0.80±0.01
tx-nocache-copy on      9403±3      9.85±0.04               0.838±0.004

nic irqs on cpu0, netperf on cpu1 (1x netperf -T1,1 -t omni -- -d send)

tx-nocache-copy off     9401±5      5.83±0.03   5.0±0.1     0.923±0.007
tx-nocache-copy on      9404±2      5.74±0.03   5.523±0.009 0.958±0.002

As a second example, here are some results from Eric Dumazet with latest
net-next.
tx-nocache-copy also leads to higher service demand

(cpu is Intel(R) Xeon(R) CPU X5660  @ 2.80GHz)

lpq83:~# ./ethtool -K eth0 tx-nocache-copy on
lpq83:~# perf stat ./netperf -H lpq84 -c
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to lpq84.prod.google.com () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  16384    10.00      9407.44   2.50     -1.00    0.522   -1.000

 Performance counter stats for './netperf -H lpq84 -c':

       4282.648396 task-clock                #    0.423 CPUs utilized
             9,348 context-switches          #    0.002 M/sec
                88 CPU-migrations            #    0.021 K/sec
               355 page-faults               #    0.083 K/sec
    11,812,797,651 cycles                    #    2.758 GHz                     [82.79%]
     9,020,522,817 stalled-cycles-frontend   #   76.36% frontend cycles idle    [82.54%]
     4,579,889,681 stalled-cycles-backend    #   38.77% backend  cycles idle    [67.33%]
     6,053,172,792 instructions              #    0.51  insns per cycle
                                             #    1.49  stalled cycles per insn [83.64%]
       597,275,583 branches                  #  139.464 M/sec                   [83.70%]
         8,960,541 branch-misses             #    1.50% of all branches         [83.65%]

      10.128990264 seconds time elapsed

lpq83:~# ./ethtool -K eth0 tx-nocache-copy off
lpq83:~# perf stat ./netperf -H lpq84 -c
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to lpq84.prod.google.com () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % U      us/KB   us/KB

 87380  16384  16384    10.00      9412.45   2.15     -1.00    0.449   -1.000

 Performance counter stats for './netperf -H lpq84 -c':

       2847.375441 task-clock                #    0.281 CPUs utilized
            11,632 context-switches          #    0.004 M/sec
                49 CPU-migrations            #    0.017 K/sec
               354 page-faults               #    0.124 K/sec
     7,646,889,749 cycles                    #    2.686 GHz                     [83.34%]
     6,115,050,032 stalled-cycles-frontend   #   79.97% frontend cycles idle    [83.31%]
     1,726,460,071 stalled-cycles-backend    #   22.58% backend  cycles idle    [66.55%]
     2,079,702,453 instructions              #    0.27  insns per cycle
                                             #    2.94  stalled cycles per insn [83.22%]
       363,773,213 branches                  #  127.757 M/sec                   [83.29%]
         4,242,732 branch-misses             #    1.17% of all branches         [83.51%]

      10.128449949 seconds time elapsed

CC: Tom Herbert &lt;therbert@google.com&gt;
Signed-off-by: Benjamin Poirier &lt;bpoirier@suse.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Zefan Li &lt;lizefan@huawei.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>iovec: make sure the caller actually wants anything in memcpy_fromiovecend</title>
<updated>2014-08-14T00:42:36+00:00</updated>
<author>
<name>Sasha Levin</name>
<email>sasha.levin@oracle.com</email>
</author>
<published>2014-08-01T03:00:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8fbbef088e95f015f89cc155a02fe64017905765'/>
<id>8fbbef088e95f015f89cc155a02fe64017905765</id>
<content type='text'>
[ Upstream commit 06ebb06d49486676272a3c030bfeef4bd969a8e6 ]

Check for cases when the caller requests 0 bytes instead of running off
and dereferencing potentially invalid iovecs.

Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 06ebb06d49486676272a3c030bfeef4bd969a8e6 ]

Check for cases when the caller requests 0 bytes instead of running off
and dereferencing potentially invalid iovecs.

Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: Correctly set segment mac_len in skb_segment().</title>
<updated>2014-08-14T00:42:36+00:00</updated>
<author>
<name>Vlad Yasevich</name>
<email>vyasevic@redhat.com</email>
</author>
<published>2014-07-31T14:33:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=80db1671bd9bf67acf9c3b21350442b4b77e7cc4'/>
<id>80db1671bd9bf67acf9c3b21350442b4b77e7cc4</id>
<content type='text'>
[ Upstream commit fcdfe3a7fa4cb74391d42b6a26dc07c20dab1d82 ]

When performing segmentation, the mac_len value is copied right
out of the original skb.  However, this value is not always set correctly
(like when the packet is VLAN-tagged) and we'll end up copying a bad
value.

One way to demonstrate this is to configure a VM which tags
packets internally and turn off VLAN acceleration on the forwarding
bridge port.  The packets show up corrupt like this:
16:18:24.985548 52:54:00:ab:be:25 &gt; 52:54:00:26:ce:a3, ethertype 802.1Q
(0x8100), length 1518: vlan 100, p 0, ethertype 0x05e0,
        0x0000:  8cdb 1c7c 8cdb 0064 4006 b59d 0a00 6402 ...|...d@.....d.
        0x0010:  0a00 6401 9e0d b441 0a5e 64ec 0330 14fa ..d....A.^d..0..
        0x0020:  29e3 01c9 f871 0000 0101 080a 000a e833)....q.........3
        0x0030:  000f 8c75 6e65 7470 6572 6600 6e65 7470 ...unetperf.netp
        0x0040:  6572 6600 6e65 7470 6572 6600 6e65 7470 erf.netperf.netp
        0x0050:  6572 6600 6e65 7470 6572 6600 6e65 7470 erf.netperf.netp
        0x0060:  6572 6600 6e65 7470 6572 6600 6e65 7470 erf.netperf.netp
        ...

This also leads to awful throughput as GSO packets are dropped and
cause retransmissions.

The solution is to set the mac_len using the values already available
in then new skb.  We've already adjusted all of the header offset, so we
might as well correctly figure out the mac_len using skb_reset_mac_len().
After this change, packets are segmented correctly and performance
is restored.

CC: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Vlad Yasevich &lt;vyasevic@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit fcdfe3a7fa4cb74391d42b6a26dc07c20dab1d82 ]

When performing segmentation, the mac_len value is copied right
out of the original skb.  However, this value is not always set correctly
(like when the packet is VLAN-tagged) and we'll end up copying a bad
value.

One way to demonstrate this is to configure a VM which tags
packets internally and turn off VLAN acceleration on the forwarding
bridge port.  The packets show up corrupt like this:
16:18:24.985548 52:54:00:ab:be:25 &gt; 52:54:00:26:ce:a3, ethertype 802.1Q
(0x8100), length 1518: vlan 100, p 0, ethertype 0x05e0,
        0x0000:  8cdb 1c7c 8cdb 0064 4006 b59d 0a00 6402 ...|...d@.....d.
        0x0010:  0a00 6401 9e0d b441 0a5e 64ec 0330 14fa ..d....A.^d..0..
        0x0020:  29e3 01c9 f871 0000 0101 080a 000a e833)....q.........3
        0x0030:  000f 8c75 6e65 7470 6572 6600 6e65 7470 ...unetperf.netp
        0x0040:  6572 6600 6e65 7470 6572 6600 6e65 7470 erf.netperf.netp
        0x0050:  6572 6600 6e65 7470 6572 6600 6e65 7470 erf.netperf.netp
        0x0060:  6572 6600 6e65 7470 6572 6600 6e65 7470 erf.netperf.netp
        ...

This also leads to awful throughput as GSO packets are dropped and
cause retransmissions.

The solution is to set the mac_len using the values already available
in then new skb.  We've already adjusted all of the header offset, so we
might as well correctly figure out the mac_len using skb_reset_mac_len().
After this change, packets are segmented correctly and performance
is restored.

CC: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Vlad Yasevich &lt;vyasevic@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: sendmsg: fix NULL pointer dereference</title>
<updated>2014-08-14T00:42:35+00:00</updated>
<author>
<name>Andrey Ryabinin</name>
<email>ryabinin.a.a@gmail.com</email>
</author>
<published>2014-07-26T17:26:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c28d71cac875c4419cef60e33b5a1f260b0002dc'/>
<id>c28d71cac875c4419cef60e33b5a1f260b0002dc</id>
<content type='text'>
[ Upstream commit 40eea803c6b2cfaab092f053248cbeab3f368412 ]

Sasha's report:
	&gt; While fuzzing with trinity inside a KVM tools guest running the latest -next
	&gt; kernel with the KASAN patchset, I've stumbled on the following spew:
	&gt;
	&gt; [ 4448.949424] ==================================================================
	&gt; [ 4448.951737] AddressSanitizer: user-memory-access on address 0
	&gt; [ 4448.952988] Read of size 2 by thread T19638:
	&gt; [ 4448.954510] CPU: 28 PID: 19638 Comm: trinity-c76 Not tainted 3.16.0-rc4-next-20140711-sasha-00046-g07d3099-dirty #813
	&gt; [ 4448.956823]  ffff88046d86ca40 0000000000000000 ffff880082f37e78 ffff880082f37a40
	&gt; [ 4448.958233]  ffffffffb6e47068 ffff880082f37a68 ffff880082f37a58 ffffffffb242708d
	&gt; [ 4448.959552]  0000000000000000 ffff880082f37a88 ffffffffb24255b1 0000000000000000
	&gt; [ 4448.961266] Call Trace:
	&gt; [ 4448.963158] dump_stack (lib/dump_stack.c:52)
	&gt; [ 4448.964244] kasan_report_user_access (mm/kasan/report.c:184)
	&gt; [ 4448.965507] __asan_load2 (mm/kasan/kasan.c:352)
	&gt; [ 4448.966482] ? netlink_sendmsg (net/netlink/af_netlink.c:2339)
	&gt; [ 4448.967541] netlink_sendmsg (net/netlink/af_netlink.c:2339)
	&gt; [ 4448.968537] ? get_parent_ip (kernel/sched/core.c:2555)
	&gt; [ 4448.970103] sock_sendmsg (net/socket.c:654)
	&gt; [ 4448.971584] ? might_fault (mm/memory.c:3741)
	&gt; [ 4448.972526] ? might_fault (./arch/x86/include/asm/current.h:14 mm/memory.c:3740)
	&gt; [ 4448.973596] ? verify_iovec (net/core/iovec.c:64)
	&gt; [ 4448.974522] ___sys_sendmsg (net/socket.c:2096)
	&gt; [ 4448.975797] ? put_lock_stats.isra.13 (./arch/x86/include/asm/preempt.h:98 kernel/locking/lockdep.c:254)
	&gt; [ 4448.977030] ? lock_release_holdtime (kernel/locking/lockdep.c:273)
	&gt; [ 4448.978197] ? lock_release_non_nested (kernel/locking/lockdep.c:3434 (discriminator 1))
	&gt; [ 4448.979346] ? check_chain_key (kernel/locking/lockdep.c:2188)
	&gt; [ 4448.980535] __sys_sendmmsg (net/socket.c:2181)
	&gt; [ 4448.981592] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2600)
	&gt; [ 4448.982773] ? trace_hardirqs_on (kernel/locking/lockdep.c:2607)
	&gt; [ 4448.984458] ? syscall_trace_enter (arch/x86/kernel/ptrace.c:1500 (discriminator 2))
	&gt; [ 4448.985621] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2600)
	&gt; [ 4448.986754] SyS_sendmmsg (net/socket.c:2201)
	&gt; [ 4448.987708] tracesys (arch/x86/kernel/entry_64.S:542)
	&gt; [ 4448.988929] ==================================================================

This reports means that we've come to netlink_sendmsg() with msg-&gt;msg_name == NULL and msg-&gt;msg_namelen &gt; 0.

After this report there was no usual "Unable to handle kernel NULL pointer dereference"
and this gave me a clue that address 0 is mapped and contains valid socket address structure in it.

This bug was introduced in f3d3342602f8bcbf37d7c46641cb9bca7618eb1c
(net: rework recvmsg handler msg_name and msg_namelen logic).
Commit message states that:
	"Set msg-&gt;msg_name = NULL if user specified a NULL in msg_name but had a
	 non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't
	 affect sendto as it would bail out earlier while trying to copy-in the
	 address."
But in fact this affects sendto when address 0 is mapped and contains
socket address structure in it. In such case copy-in address will succeed,
verify_iovec() function will successfully exit with msg-&gt;msg_namelen &gt; 0
and msg-&gt;msg_name == NULL.

This patch fixes it by setting msg_namelen to 0 if msg_name == NULL.

Cc: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Signed-off-by: Andrey Ryabinin &lt;a.ryabinin@samsung.com&gt;
Acked-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 40eea803c6b2cfaab092f053248cbeab3f368412 ]

Sasha's report:
	&gt; While fuzzing with trinity inside a KVM tools guest running the latest -next
	&gt; kernel with the KASAN patchset, I've stumbled on the following spew:
	&gt;
	&gt; [ 4448.949424] ==================================================================
	&gt; [ 4448.951737] AddressSanitizer: user-memory-access on address 0
	&gt; [ 4448.952988] Read of size 2 by thread T19638:
	&gt; [ 4448.954510] CPU: 28 PID: 19638 Comm: trinity-c76 Not tainted 3.16.0-rc4-next-20140711-sasha-00046-g07d3099-dirty #813
	&gt; [ 4448.956823]  ffff88046d86ca40 0000000000000000 ffff880082f37e78 ffff880082f37a40
	&gt; [ 4448.958233]  ffffffffb6e47068 ffff880082f37a68 ffff880082f37a58 ffffffffb242708d
	&gt; [ 4448.959552]  0000000000000000 ffff880082f37a88 ffffffffb24255b1 0000000000000000
	&gt; [ 4448.961266] Call Trace:
	&gt; [ 4448.963158] dump_stack (lib/dump_stack.c:52)
	&gt; [ 4448.964244] kasan_report_user_access (mm/kasan/report.c:184)
	&gt; [ 4448.965507] __asan_load2 (mm/kasan/kasan.c:352)
	&gt; [ 4448.966482] ? netlink_sendmsg (net/netlink/af_netlink.c:2339)
	&gt; [ 4448.967541] netlink_sendmsg (net/netlink/af_netlink.c:2339)
	&gt; [ 4448.968537] ? get_parent_ip (kernel/sched/core.c:2555)
	&gt; [ 4448.970103] sock_sendmsg (net/socket.c:654)
	&gt; [ 4448.971584] ? might_fault (mm/memory.c:3741)
	&gt; [ 4448.972526] ? might_fault (./arch/x86/include/asm/current.h:14 mm/memory.c:3740)
	&gt; [ 4448.973596] ? verify_iovec (net/core/iovec.c:64)
	&gt; [ 4448.974522] ___sys_sendmsg (net/socket.c:2096)
	&gt; [ 4448.975797] ? put_lock_stats.isra.13 (./arch/x86/include/asm/preempt.h:98 kernel/locking/lockdep.c:254)
	&gt; [ 4448.977030] ? lock_release_holdtime (kernel/locking/lockdep.c:273)
	&gt; [ 4448.978197] ? lock_release_non_nested (kernel/locking/lockdep.c:3434 (discriminator 1))
	&gt; [ 4448.979346] ? check_chain_key (kernel/locking/lockdep.c:2188)
	&gt; [ 4448.980535] __sys_sendmmsg (net/socket.c:2181)
	&gt; [ 4448.981592] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2600)
	&gt; [ 4448.982773] ? trace_hardirqs_on (kernel/locking/lockdep.c:2607)
	&gt; [ 4448.984458] ? syscall_trace_enter (arch/x86/kernel/ptrace.c:1500 (discriminator 2))
	&gt; [ 4448.985621] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2600)
	&gt; [ 4448.986754] SyS_sendmmsg (net/socket.c:2201)
	&gt; [ 4448.987708] tracesys (arch/x86/kernel/entry_64.S:542)
	&gt; [ 4448.988929] ==================================================================

This reports means that we've come to netlink_sendmsg() with msg-&gt;msg_name == NULL and msg-&gt;msg_namelen &gt; 0.

After this report there was no usual "Unable to handle kernel NULL pointer dereference"
and this gave me a clue that address 0 is mapped and contains valid socket address structure in it.

This bug was introduced in f3d3342602f8bcbf37d7c46641cb9bca7618eb1c
(net: rework recvmsg handler msg_name and msg_namelen logic).
Commit message states that:
	"Set msg-&gt;msg_name = NULL if user specified a NULL in msg_name but had a
	 non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't
	 affect sendto as it would bail out earlier while trying to copy-in the
	 address."
But in fact this affects sendto when address 0 is mapped and contains
socket address structure in it. In such case copy-in address will succeed,
verify_iovec() function will successfully exit with msg-&gt;msg_namelen &gt; 0
and msg-&gt;msg_name == NULL.

This patch fixes it by setting msg_namelen to 0 if msg_name == NULL.

Cc: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Reported-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Signed-off-by: Andrey Ryabinin &lt;a.ryabinin@samsung.com&gt;
Acked-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>inetpeer: get rid of ip_id_count</title>
<updated>2014-08-14T00:42:35+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2014-06-02T12:26:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ad52eef552c7896ec6024ee72fc126167fe5c4e2'/>
<id>ad52eef552c7896ec6024ee72fc126167fe5c4e2</id>
<content type='text'>
[ Upstream commit 73f156a6e8c1074ac6327e0abd1169e95eb66463 ]

Ideally, we would need to generate IP ID using a per destination IP
generator.

linux kernels used inet_peer cache for this purpose, but this had a huge
cost on servers disabling MTU discovery.

1) each inet_peer struct consumes 192 bytes

2) inetpeer cache uses a binary tree of inet_peer structs,
   with a nominal size of ~66000 elements under load.

3) lookups in this tree are hitting a lot of cache lines, as tree depth
   is about 20.

4) If server deals with many tcp flows, we have a high probability of
   not finding the inet_peer, allocating a fresh one, inserting it in
   the tree with same initial ip_id_count, (cf secure_ip_id())

5) We garbage collect inet_peer aggressively.

IP ID generation do not have to be 'perfect'

Goal is trying to avoid duplicates in a short period of time,
so that reassembly units have a chance to complete reassembly of
fragments belonging to one message before receiving other fragments
with a recycled ID.

We simply use an array of generators, and a Jenkin hash using the dst IP
as a key.

ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it
belongs (it is only used from this file)

secure_ip_id() and secure_ipv6_id() no longer are needed.

Rename ip_select_ident_more() to ip_select_ident_segs() to avoid
unnecessary decrement/increment of the number of segments.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 73f156a6e8c1074ac6327e0abd1169e95eb66463 ]

Ideally, we would need to generate IP ID using a per destination IP
generator.

linux kernels used inet_peer cache for this purpose, but this had a huge
cost on servers disabling MTU discovery.

1) each inet_peer struct consumes 192 bytes

2) inetpeer cache uses a binary tree of inet_peer structs,
   with a nominal size of ~66000 elements under load.

3) lookups in this tree are hitting a lot of cache lines, as tree depth
   is about 20.

4) If server deals with many tcp flows, we have a high probability of
   not finding the inet_peer, allocating a fresh one, inserting it in
   the tree with same initial ip_id_count, (cf secure_ip_id())

5) We garbage collect inet_peer aggressively.

IP ID generation do not have to be 'perfect'

Goal is trying to avoid duplicates in a short period of time,
so that reassembly units have a chance to complete reassembly of
fragments belonging to one message before receiving other fragments
with a recycled ID.

We simply use an array of generators, and a Jenkin hash using the dst IP
as a key.

ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it
belongs (it is only used from this file)

secure_ip_id() and secure_ipv6_id() no longer are needed.

Rename ip_select_ident_more() to ip_select_ident_segs() to avoid
unnecessary decrement/increment of the number of segments.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>skbuff: skb_segment: orphan frags before copying</title>
<updated>2014-07-01T03:01:33+00:00</updated>
<author>
<name>Michael S. Tsirkin</name>
<email>mst@redhat.com</email>
</author>
<published>2014-03-10T17:28:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2edae61bce495df81c58eb0b93faac301de849c7'/>
<id>2edae61bce495df81c58eb0b93faac301de849c7</id>
<content type='text'>
commit 1fd819ecb90cc9b822cd84d3056ddba315d3340f upstream.

skb_segment copies frags around, so we need
to copy them carefully to avoid accessing
user memory after reporting completion to userspace
through a callback.

skb_segment doesn't normally happen on datapath:
TSO needs to be disabled - so disabling zero copy
in this case does not look like a big deal.

Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Acked-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 3.2.  As skb_segment() only supports page-frags *or* a
 frag list, there is no need for the additional frag_skb pointer or the
 preparatory renaming.]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 1fd819ecb90cc9b822cd84d3056ddba315d3340f upstream.

skb_segment copies frags around, so we need
to copy them carefully to avoid accessing
user memory after reporting completion to userspace
through a callback.

skb_segment doesn't normally happen on datapath:
TSO needs to be disabled - so disabling zero copy
in this case does not look like a big deal.

Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Acked-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 3.2.  As skb_segment() only supports page-frags *or* a
 frag list, there is no need for the additional frag_skb pointer or the
 preparatory renaming.]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>skbuff: export skb_copy_ubufs</title>
<updated>2014-07-01T03:01:33+00:00</updated>
<author>
<name>Michael S. Tsirkin</name>
<email>mst@redhat.com</email>
</author>
<published>2012-07-20T09:23:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2f3ca8e5606f49ff02a0133fdbe2e6b852cb1e64'/>
<id>2f3ca8e5606f49ff02a0133fdbe2e6b852cb1e64</id>
<content type='text'>
commit dcc0fb782b3a6e2abfeaaeb45dd88ed09596be0f upstream.

Export skb_copy_ubufs so that modules can orphan frags.

Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit dcc0fb782b3a6e2abfeaaeb45dd88ed09596be0f upstream.

Export skb_copy_ubufs so that modules can orphan frags.

Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
</feed>
