<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/net/core/dev.c, branch v3.2.3</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/core: fix rollback handler in register_netdevice_notifier</title>
<updated>2011-12-01T04:43:07+00:00</updated>
<author>
<name>RongQing.Li</name>
<email>roy.qing.li@gmail.com</email>
</author>
<published>2011-12-01T04:43:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8f891489866ec62a87494eff3ed17c88152c32d4'/>
<id>8f891489866ec62a87494eff3ed17c88152c32d4</id>
<content type='text'>
Within nested statements, the break statement terminates only the
do, for, switch, or while statement that immediately encloses it,
So replace the break with goto.

Signed-off-by: RongQing.Li &lt;roy.qing.li@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Within nested statements, the break statement terminates only the
do, for, switch, or while statement that immediately encloses it,
So replace the break with goto.

Signed-off-by: RongQing.Li &lt;roy.qing.li@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: Fix corruption in /proc/*/net/dev_mcast</title>
<updated>2011-11-28T23:07:29+00:00</updated>
<author>
<name>Anton Blanchard</name>
<email>anton@samba.org</email>
</author>
<published>2011-11-27T21:14:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5cac98dd06bc43a7baab3523184f70fd359e9f35'/>
<id>5cac98dd06bc43a7baab3523184f70fd359e9f35</id>
<content type='text'>
I just hit this during my testing. Isn't there another bug lurking?

BUG kmalloc-8: Redzone overwritten

INFO: 0xc0000000de9dec48-0xc0000000de9dec4b. First byte 0x0 instead of 0xcc
INFO: Allocated in .__seq_open_private+0x30/0xa0 age=0 cpu=5 pid=3896
	.__kmalloc+0x1e0/0x2d0
	.__seq_open_private+0x30/0xa0
	.seq_open_net+0x60/0xe0
	.dev_mc_seq_open+0x4c/0x70
	.proc_reg_open+0xd8/0x260
	.__dentry_open.clone.11+0x2b8/0x400
	.do_last+0xf4/0x950
	.path_openat+0xf8/0x480
	.do_filp_open+0x48/0xc0
	.do_sys_open+0x140/0x250
	syscall_exit+0x0/0x40

dev_mc_seq_ops uses dev_seq_start/next/stop but only allocates
sizeof(struct seq_net_private) of private data, whereas it expects
sizeof(struct dev_iter_state):

struct dev_iter_state {
	struct seq_net_private p;
	unsigned int pos; /* bucket &lt;&lt; BUCKET_SPACE + offset */
};

Create dev_seq_open_ops and use it so we don't have to expose
struct dev_iter_state.

[ Problem added by commit f04565ddf52e4 (dev: use name hash for
  dev_seq_ops) -Eric ]

Signed-off-by: Anton Blanchard &lt;anton@samba.org&gt;
Acked-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
I just hit this during my testing. Isn't there another bug lurking?

BUG kmalloc-8: Redzone overwritten

INFO: 0xc0000000de9dec48-0xc0000000de9dec4b. First byte 0x0 instead of 0xcc
INFO: Allocated in .__seq_open_private+0x30/0xa0 age=0 cpu=5 pid=3896
	.__kmalloc+0x1e0/0x2d0
	.__seq_open_private+0x30/0xa0
	.seq_open_net+0x60/0xe0
	.dev_mc_seq_open+0x4c/0x70
	.proc_reg_open+0xd8/0x260
	.__dentry_open.clone.11+0x2b8/0x400
	.do_last+0xf4/0x950
	.path_openat+0xf8/0x480
	.do_filp_open+0x48/0xc0
	.do_sys_open+0x140/0x250
	syscall_exit+0x0/0x40

dev_mc_seq_ops uses dev_seq_start/next/stop but only allocates
sizeof(struct seq_net_private) of private data, whereas it expects
sizeof(struct dev_iter_state):

struct dev_iter_state {
	struct seq_net_private p;
	unsigned int pos; /* bucket &lt;&lt; BUCKET_SPACE + offset */
};

Create dev_seq_open_ops and use it so we don't have to expose
struct dev_iter_state.

[ Problem added by commit f04565ddf52e4 (dev: use name hash for
  dev_seq_ops) -Eric ]

Signed-off-by: Anton Blanchard &lt;anton@samba.org&gt;
Acked-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>vlan: allow nested vlan_do_receive()</title>
<updated>2011-10-30T08:43:30+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>eric.dumazet@gmail.com</email>
</author>
<published>2011-10-29T06:13:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6a32e4f9dd9219261f8856f817e6655114cfec2f'/>
<id>6a32e4f9dd9219261f8856f817e6655114cfec2f</id>
<content type='text'>
commit 2425717b27eb (net: allow vlan traffic to be received under bond)
broke ARP processing on vlan on top of bonding.

       +-------+
eth0 --| bond0 |---bond0.103
eth1 --|       |
       +-------+

52870.115435: skb_gro_reset_offset &lt;-napi_gro_receive
52870.115435: dev_gro_receive &lt;-napi_gro_receive
52870.115435: napi_skb_finish &lt;-napi_gro_receive
52870.115435: netif_receive_skb &lt;-napi_skb_finish
52870.115435: get_rps_cpu &lt;-netif_receive_skb
52870.115435: __netif_receive_skb &lt;-netif_receive_skb
52870.115436: vlan_do_receive &lt;-__netif_receive_skb
52870.115436: bond_handle_frame &lt;-__netif_receive_skb
52870.115436: vlan_do_receive &lt;-__netif_receive_skb
52870.115436: arp_rcv &lt;-__netif_receive_skb
52870.115436: kfree_skb &lt;-arp_rcv

Packet is dropped in arp_rcv() because its pkt_type was set to
PACKET_OTHERHOST in the first vlan_do_receive() call, since no eth0.103
exists.

We really need to change pkt_type only if no more rx_handler is about to
be called for the packet.

Signed-off-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Reviewed-by: Jiri Pirko &lt;jpirko@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2425717b27eb (net: allow vlan traffic to be received under bond)
broke ARP processing on vlan on top of bonding.

       +-------+
eth0 --| bond0 |---bond0.103
eth1 --|       |
       +-------+

52870.115435: skb_gro_reset_offset &lt;-napi_gro_receive
52870.115435: dev_gro_receive &lt;-napi_gro_receive
52870.115435: napi_skb_finish &lt;-napi_gro_receive
52870.115435: netif_receive_skb &lt;-napi_skb_finish
52870.115435: get_rps_cpu &lt;-netif_receive_skb
52870.115435: __netif_receive_skb &lt;-netif_receive_skb
52870.115436: vlan_do_receive &lt;-__netif_receive_skb
52870.115436: bond_handle_frame &lt;-__netif_receive_skb
52870.115436: vlan_do_receive &lt;-__netif_receive_skb
52870.115436: arp_rcv &lt;-__netif_receive_skb
52870.115436: kfree_skb &lt;-arp_rcv

Packet is dropped in arp_rcv() because its pkt_type was set to
PACKET_OTHERHOST in the first vlan_do_receive() call, since no eth0.103
exists.

We really need to change pkt_type only if no more rx_handler is about to
be called for the packet.

Signed-off-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Reviewed-by: Jiri Pirko &lt;jpirko@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next</title>
<updated>2011-10-25T11:25:22+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-10-25T11:25:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8a9ea3237e7eb5c25f09e429ad242ae5a3d5ea22'/>
<id>8a9ea3237e7eb5c25f09e429ad242ae5a3d5ea22</id>
<content type='text'>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1745 commits)
  dp83640: free packet queues on remove
  dp83640: use proper function to free transmit time stamping packets
  ipv6: Do not use routes from locally generated RAs
  |PATCH net-next] tg3: add tx_dropped counter
  be2net: don't create multiple RX/TX rings in multi channel mode
  be2net: don't create multiple TXQs in BE2
  be2net: refactor VF setup/teardown code into be_vf_setup/clear()
  be2net: add vlan/rx-mode/flow-control config to be_setup()
  net_sched: cls_flow: use skb_header_pointer()
  ipv4: avoid useless call of the function check_peer_pmtu
  TCP: remove TCP_DEBUG
  net: Fix driver name for mdio-gpio.c
  ipv4: tcp: fix TOS value in ACK messages sent from TIME_WAIT
  rtnetlink: Add missing manual netlink notification in dev_change_net_namespaces
  ipv4: fix ipsec forward performance regression
  jme: fix irq storm after suspend/resume
  route: fix ICMP redirect validation
  net: hold sock reference while processing tx timestamps
  tcp: md5: add more const attributes
  Add ethtool -g support to virtio_net
  ...

Fix up conflicts in:
 - drivers/net/Kconfig:
	The split-up generated a trivial conflict with removal of a
	stale reference to Documentation/networking/net-modules.txt.
	Remove it from the new location instead.
 - fs/sysfs/dir.c:
	Fairly nasty conflicts with the sysfs rb-tree usage, conflicting
	with Eric Biederman's changes for tagged directories.
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1745 commits)
  dp83640: free packet queues on remove
  dp83640: use proper function to free transmit time stamping packets
  ipv6: Do not use routes from locally generated RAs
  |PATCH net-next] tg3: add tx_dropped counter
  be2net: don't create multiple RX/TX rings in multi channel mode
  be2net: don't create multiple TXQs in BE2
  be2net: refactor VF setup/teardown code into be_vf_setup/clear()
  be2net: add vlan/rx-mode/flow-control config to be_setup()
  net_sched: cls_flow: use skb_header_pointer()
  ipv4: avoid useless call of the function check_peer_pmtu
  TCP: remove TCP_DEBUG
  net: Fix driver name for mdio-gpio.c
  ipv4: tcp: fix TOS value in ACK messages sent from TIME_WAIT
  rtnetlink: Add missing manual netlink notification in dev_change_net_namespaces
  ipv4: fix ipsec forward performance regression
  jme: fix irq storm after suspend/resume
  route: fix ICMP redirect validation
  net: hold sock reference while processing tx timestamps
  tcp: md5: add more const attributes
  Add ethtool -g support to virtio_net
  ...

Fix up conflicts in:
 - drivers/net/Kconfig:
	The split-up generated a trivial conflict with removal of a
	stale reference to Documentation/networking/net-modules.txt.
	Remove it from the new location instead.
 - fs/sysfs/dir.c:
	Fairly nasty conflicts with the sysfs rb-tree usage, conflicting
	with Eric Biederman's changes for tagged directories.
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core</title>
<updated>2011-10-25T10:13:59+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2011-10-25T10:13:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2d03423b2319cc854adeb28a03f65de5b5e0ab63'/>
<id>2d03423b2319cc854adeb28a03f65de5b5e0ab63</id>
<content type='text'>
* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (38 commits)
  mm: memory hotplug: Check if pages are correctly reserved on a per-section basis
  Revert "memory hotplug: Correct page reservation checking"
  Update email address for stable patch submission
  dynamic_debug: fix undefined reference to `__netdev_printk'
  dynamic_debug: use a single printk() to emit messages
  dynamic_debug: remove num_enabled accounting
  dynamic_debug: consolidate repetitive struct _ddebug descriptor definitions
  uio: Support physical addresses &gt;32 bits on 32-bit systems
  sysfs: add unsigned long cast to prevent compile warning
  drivers: base: print rejected matches with DEBUG_DRIVER
  memory hotplug: Correct page reservation checking
  memory hotplug: Refuse to add unaligned memory regions
  remove the messy code file Documentation/zh_CN/SubmitChecklist
  ARM: mxc: convert device creation to use platform_device_register_full
  new helper to create platform devices with dma mask
  docs/driver-model: Update device class docs
  docs/driver-model: Document device.groups
  kobj_uevent: Ignore if some listeners cannot handle message
  dynamic_debug: make netif_dbg() call __netdev_printk()
  dynamic_debug: make netdev_dbg() call __netdev_printk()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (38 commits)
  mm: memory hotplug: Check if pages are correctly reserved on a per-section basis
  Revert "memory hotplug: Correct page reservation checking"
  Update email address for stable patch submission
  dynamic_debug: fix undefined reference to `__netdev_printk'
  dynamic_debug: use a single printk() to emit messages
  dynamic_debug: remove num_enabled accounting
  dynamic_debug: consolidate repetitive struct _ddebug descriptor definitions
  uio: Support physical addresses &gt;32 bits on 32-bit systems
  sysfs: add unsigned long cast to prevent compile warning
  drivers: base: print rejected matches with DEBUG_DRIVER
  memory hotplug: Correct page reservation checking
  memory hotplug: Refuse to add unaligned memory regions
  remove the messy code file Documentation/zh_CN/SubmitChecklist
  ARM: mxc: convert device creation to use platform_device_register_full
  new helper to create platform devices with dma mask
  docs/driver-model: Update device class docs
  docs/driver-model: Document device.groups
  kobj_uevent: Ignore if some listeners cannot handle message
  dynamic_debug: make netif_dbg() call __netdev_printk()
  dynamic_debug: make netdev_dbg() call __netdev_printk()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'master' of ra.kernel.org:/pub/scm/linux/kernel/git/davem/net</title>
<updated>2011-10-24T22:18:09+00:00</updated>
<author>
<name>David S. Miller</name>
<email>davem@davemloft.net</email>
</author>
<published>2011-10-24T22:18:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1805b2f04855f07afe3a71d620a68f483b0ed74f'/>
<id>1805b2f04855f07afe3a71d620a68f483b0ed74f</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>rtnetlink: Add missing manual netlink notification in dev_change_net_namespaces</title>
<updated>2011-10-24T07:03:37+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2011-10-21T06:24:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d2237d35748e7f448a9c2d9dc6a85ef637466e24'/>
<id>d2237d35748e7f448a9c2d9dc6a85ef637466e24</id>
<content type='text'>
Renato Westphal noticed that since commit a2835763e130c343ace5320c20d33c281e7097b7
"rtnetlink: handle rtnl_link netlink notifications manually" was merged
we no longer send a netlink message when a networking device is moved
from one network namespace to another.

Fix this by adding the missing manual notification in dev_change_net_namespaces.

Since all network devices that are processed by dev_change_net_namspaces are
in the initialized state the complicated tests that guard the manual
rtmsg_ifinfo calls in rollback_registered and register_netdevice are
unnecessary and we can just perform a plain notification.

Cc: stable@kernel.org
Tested-by: Renato Westphal &lt;renatowestphal@gmail.com&gt;
Signed-off-by: Eric W. Biederman &lt;ebiederm@xmission.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Renato Westphal noticed that since commit a2835763e130c343ace5320c20d33c281e7097b7
"rtnetlink: handle rtnl_link netlink notifications manually" was merged
we no longer send a netlink message when a networking device is moved
from one network namespace to another.

Fix this by adding the missing manual notification in dev_change_net_namespaces.

Since all network devices that are processed by dev_change_net_namspaces are
in the initialized state the complicated tests that guard the manual
rtmsg_ifinfo calls in rollback_registered and register_netdevice are
unnecessary and we can just perform a plain notification.

Cc: stable@kernel.org
Tested-by: Renato Westphal &lt;renatowestphal@gmail.com&gt;
Signed-off-by: Eric W. Biederman &lt;ebiederm@xmission.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>dev: use name hash for dev_seq_ops</title>
<updated>2011-10-21T06:54:38+00:00</updated>
<author>
<name>Mihai Maruseac</name>
<email>mihai.maruseac@gmail.com</email>
</author>
<published>2011-10-20T20:45:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f04565ddf52e401880f8ba51de0dff8ba51c99fd'/>
<id>f04565ddf52e401880f8ba51de0dff8ba51c99fd</id>
<content type='text'>
Instead of using the dev-&gt;next chain and trying to resync at each call to
dev_seq_start, use the name hash, keeping the bucket and the offset in
seq-&gt;private field.

Tests revealed the following results for ifconfig &gt; /dev/null
	* 1000 interfaces:
		* 0.114s without patch
		* 0.089s with patch
	* 3000 interfaces:
		* 0.489s without patch
		* 0.110s with patch
	* 5000 interfaces:
		* 1.363s without patch
		* 0.250s with patch
	* 128000 interfaces (other setup):
		* ~100s without patch
		* ~30s with patch

Signed-off-by: Mihai Maruseac &lt;mmaruseac@ixiacom.com&gt;
Signed-off-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Instead of using the dev-&gt;next chain and trying to resync at each call to
dev_seq_start, use the name hash, keeping the bucket and the offset in
seq-&gt;private field.

Tests revealed the following results for ifconfig &gt; /dev/null
	* 1000 interfaces:
		* 0.114s without patch
		* 0.089s with patch
	* 3000 interfaces:
		* 0.489s without patch
		* 0.110s with patch
	* 5000 interfaces:
		* 1.363s without patch
		* 0.250s with patch
	* 128000 interfaces (other setup):
		* ~100s without patch
		* ~30s with patch

Signed-off-by: Mihai Maruseac &lt;mmaruseac@ixiacom.com&gt;
Signed-off-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: validate HWTSTAMP ioctl parameters</title>
<updated>2011-10-19T21:00:35+00:00</updated>
<author>
<name>Richard Cochran</name>
<email>richard.cochran@omicron.at</email>
</author>
<published>2011-10-19T21:00:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4dc360c5e7e155373bffbb3c1f7ea0022dee650c'/>
<id>4dc360c5e7e155373bffbb3c1f7ea0022dee650c</id>
<content type='text'>
This patch adds a sanity check on the values provided by user space for
the hardware time stamping configuration. If the values lie outside of
the absolute limits, then the ioctl request will be denied.

Signed-off-by: Richard Cochran &lt;richard.cochran@omicron.at&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds a sanity check on the values provided by user space for
the hardware time stamping configuration. If the values lie outside of
the absolute limits, then the ioctl request will be denied.

Signed-off-by: Richard Cochran &lt;richard.cochran@omicron.at&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: Move rcu_barrier from rollback_registered_many to netdev_run_todo.</title>
<updated>2011-10-19T20:59:42+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2011-10-13T22:25:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=850a545bd8a41648445bfc5541afe36ca105b0b8'/>
<id>850a545bd8a41648445bfc5541afe36ca105b0b8</id>
<content type='text'>
This patch moves the rcu_barrier from rollback_registered_many
(inside the rtnl_lock) into netdev_run_todo (just outside the rtnl_lock).
This allows us to gain the full benefit of sychronize_net calling
synchronize_rcu_expedited when the rtnl_lock is held.

The rcu_barrier in rollback_registered_many was originally a synchronize_net
but was promoted to be a rcu_barrier() when it was found that people were
unnecessarily hitting the 250ms wait in netdev_wait_allrefs().  Changing
the rcu_barrier back to a synchronize_net is therefore safe.

Since we only care about waiting for the rcu callbacks before we get
to netdev_wait_allrefs() it is also safe to move the wait into
netdev_run_todo.

This was tested by creating and destroying 1000 tap devices and observing
/proc/lock_stat.  /proc/lock_stat reports this change reduces the hold
times of the rtnl_lock by a factor of 10.  There was no observable
difference in the amount of time it takes to destroy a network device.

Signed-off-by: Eric W. Biederman &lt;ebiederm@xmission.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
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<pre>
This patch moves the rcu_barrier from rollback_registered_many
(inside the rtnl_lock) into netdev_run_todo (just outside the rtnl_lock).
This allows us to gain the full benefit of sychronize_net calling
synchronize_rcu_expedited when the rtnl_lock is held.

The rcu_barrier in rollback_registered_many was originally a synchronize_net
but was promoted to be a rcu_barrier() when it was found that people were
unnecessarily hitting the 250ms wait in netdev_wait_allrefs().  Changing
the rcu_barrier back to a synchronize_net is therefore safe.

Since we only care about waiting for the rcu callbacks before we get
to netdev_wait_allrefs() it is also safe to move the wait into
netdev_run_todo.

This was tested by creating and destroying 1000 tap devices and observing
/proc/lock_stat.  /proc/lock_stat reports this change reduces the hold
times of the rtnl_lock by a factor of 10.  There was no observable
difference in the amount of time it takes to destroy a network device.

Signed-off-by: Eric W. Biederman &lt;ebiederm@xmission.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
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