In order for the network device ops get_stats call to be immutable, the handling
of the default internal network device stats block has to be changed. Add a new
helper function which replaces the old use of internal_get_stats.
Note: change return code to make it clear that the caller should not
go changing the returned statistics.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch changes the network device internal API to move adminstrative
operations out of the network device structure and into a separate structure.
This patch involves some hackery to maintain compatablity between the
new and old model, so all 300+ drivers don't have to be changed at once.
For drivers that aren't converted yet, the netdevice_ops virt function list
still resides in the net_device structure. For old protocols, the new
net_device_ops are copied out to the old net_device pointers.
After the transistion is completed the nag message can be changed to
an WARN_ON, and the compatiablity code can be made configurable.
Some function pointers aren't moved:
* destructor can't be in net_device_ops because
it may need to be referenced after the module is unloaded.
* neighbor setup is manipulated in a couple of places that need special
consideration
* hard_start_xmit is in the fast path for transmit.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The first argument to csum_partial is const void *
casts to char/u8 * are not necessary
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Converting /proc/net/protocols to be namespace aware is quite easy
and permits us to use sock_prot_inuse_get().
This provides seperate counters for each protocol. For example
we can really count TCPv6 sockets and TCPv4 sockets, while previously,
we had the same value, and this value was not namespace aware.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unlike ifconfig, iproute doesn't report an error when setting
an interface up fails:
(example: put wireless network mac80211 interface into repeater mode
with iwconfig but do not set a peer MAC address, it should fail with
-ENOLINK)
without patch:
# ip link set wlan0 up ; echo $?
0
#
with patch:
# ip link set wlan0 up ; echo $?
RTNETLINK answers: Link has been severed
2
#
Propagate the return value from dev_change_flags() to fix this.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Technically, patch changes format for modules, but I think nobody cares.
-86dd :ipv6:ipv6_rcv+0x0
+86dd ipv6_rcv+0x0/0x400 [ipv6]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
RCU was added to UDP lookups, using a fast infrastructure :
- sockets kmem_cache use SLAB_DESTROY_BY_RCU and dont pay the
price of call_rcu() at freeing time.
- hlist_nulls permits to use few memory barriers.
This patch uses same infrastructure for TCP/DCCP established
and timewait sockets.
Thanks to SLAB_DESTROY_BY_RCU, no slowdown for applications
using short lived TCP connections. A followup patch, converting
rwlocks to spinlocks will even speedup this case.
__inet_lookup_established() is pretty fast now we dont have to
dirty a contended cache line (read_lock/read_unlock)
Only established and timewait hashtable are converted to RCU
(bind table and listen table are still using traditional locking)
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is the next page of the scm recursion story (the commit
f8d570a4 net: Fix recursive descent in __scm_destroy()).
In function scm_fp_dup(), the INIT_LIST_HEAD(&fpl->list) of newly
created fpl is done *before* the subsequent memcpy from the old
structure and thus the freshly initialized list is overwritten.
But that's OK, since this initialization is not required at all,
since the fpl->list is list_add-ed at the destruction time in any
case (and is unused in other code), so I propose to drop both
initializations, rather than moving it after the memcpy.
Please, correct me if I miss something significant.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
During tbench/oprofile sessions, I found that dst_release() was in third position.
CPU: Core 2, speed 2999.68 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000
samples % symbol name
483726 9.0185 __copy_user_zeroing_intel
191466 3.5697 __copy_user_intel
185475 3.4580 dst_release
175114 3.2648 ip_queue_xmit
153447 2.8608 tcp_sendmsg
108775 2.0280 tcp_recvmsg
102659 1.9140 sysenter_past_esp
101450 1.8914 tcp_current_mss
95067 1.7724 __copy_from_user_ll
86531 1.6133 tcp_transmit_skb
Of course, all CPUS fight on the dst_entry associated with 127.0.0.1
Instead of first checking the refcount value, then decrement it,
we use atomic_dec_return() to help CPU to make the right memory transaction
(ie getting the cache line in exclusive mode)
dst_release() is now at the fifth position, and tbench a litle bit faster ;)
CPU: Core 2, speed 3000.1 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000
samples % symbol name
647107 8.8072 __copy_user_zeroing_intel
258840 3.5229 ip_queue_xmit
258302 3.5155 __copy_user_intel
209629 2.8531 tcp_sendmsg
165632 2.2543 dst_release
149232 2.0311 tcp_current_mss
147821 2.0119 tcp_recvmsg
137893 1.8767 sysenter_past_esp
127473 1.7349 __copy_from_user_ll
121308 1.6510 ip_finish_output
118510 1.6129 tcp_transmit_skb
109295 1.4875 tcp_v4_rcv
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
fix this warning:
net/bluetooth/af_bluetooth.c:60: warning: ‘bt_key_strings’ defined but not used
net/bluetooth/af_bluetooth.c:71: warning: ‘bt_slock_key_strings’ defined but not used
this is a lockdep macro problem in the !LOCKDEP case.
We cannot convert it to an inline because the macro works on multiple types,
but we can mark the parameter used.
[ also clean up a misaligned tab in sock_lock_init_class_and_name() ]
[ also remove #ifdefs from around af_family_clock_key strings - which
were certainly added to get rid of the ugly build warnings. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Using read_pnet() and write_pnet() in neighbour code ease the reading
of code.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
->pde isn't actually needed, since name is stashed in ->id.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since skb_reset_tail_pointer() reads skb->data, we need to set
skb->data before calling skb_reset_tail_pointer(). This was causing
spurious skb_over_panic()s from skb_put() being called on a recycled
skb that had its skb->tail set to beyond where it should have been.
Bug report from Peter van Valderen <linux@ddcrew.com>.
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While testing pktgen, I found that sometimes my configurations from
previous runs would be left over, particularly when going from a test
with 8 threads down to a test with 4 threads.
This adds new functionality to pktgen where you can call
pgset "reset"
and it will be just like you just insmod'ed pktgen again.
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
I was recently hunting a bug that occurred in network namespace
cleanup. In looking at the code it became apparrent that we have
and will continue to have cases where if we have anything going
on in a network namespace there will be assumptions that the
loopback device is present. Things like sending igmp unsubscribe
messages when we bring down network devices invokes the routing
code which assumes that at least the loopback driver is present.
Therefore to avoid magic initcall ordering hackery that is hard
to follow and hard to get right insert a call to register the
loopback device directly from net_dev_init(). This guarantes
that the loopback device is the first device registered and
the last network device to go away.
But do it carefully so we register the loopback device after
we clear dev_boot_phase.
Signed-off-by: Eric W. Biederman <ebiederm@maxwell.aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We need to setup the network namespace state before we register
the notifier. Otherwise if a network device is already registered
we get a nasty NULL pointer dereference.
Signed-off-by: Eric W. Biederman <ebiederm@maxwell.aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It's called from __init code only. And__devinit in generic networking code
is pretty strange :^)
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
__scm_destroy() walks the list of file descriptors in the scm_fp_list
pointed to by the scm_cookie argument.
Those, in turn, can close sockets and invoke __scm_destroy() again.
There is nothing which limits how deeply this can occur.
The idea for how to fix this is from Linus. Basically, we do all of
the fput()s at the top level by collecting all of the scm_fp_list
objects hit by an fput(). Inside of the initial __scm_destroy() we
keep running the list until it is empty.
Signed-off-by: David S. Miller <davem@davemloft.net>
I have been tracking for a while a case where when the
network namespace exits the cleanup gets stck in an
endless precessess of:
unregister_netdevice: waiting for lo to become free. Usage count = 3
unregister_netdevice: waiting for lo to become free. Usage count = 3
unregister_netdevice: waiting for lo to become free. Usage count = 3
unregister_netdevice: waiting for lo to become free. Usage count = 3
unregister_netdevice: waiting for lo to become free. Usage count = 3
unregister_netdevice: waiting for lo to become free. Usage count = 3
unregister_netdevice: waiting for lo to become free. Usage count = 3
It turns out that if you listen on a multicast address an unsubscribe
packet is sent when the network device goes down. If you shutdown
the network namespace without carefully cleaning up this can trigger
the unsubscribe packet to be sent over the loopback interface while
the network namespace is going down.
All of which is fine except when we drop the packet and forget to
free it leaking the skb and the dst entry attached to. As it
turns out the dst entry hold a reference to the idev which holds
the dev and keeps everything from being cleaned up. Yuck!
By fixing my earlier thinko and add the needed kfree_skb and everything
cleans up beautifully.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I was recently hunting a bug that occurred in network namespace
cleanup. In looking at the code it became apparrent that we have
and will continue to have cases where if we have anything going
on in a network namespace there will be assumptions that the
loopback device is present. Things like sending igmp unsubscribe
messages when we bring down network devices invokes the routing
code which assumes that at least the loopback driver is present.
Therefore to avoid magic initcall ordering hackery that is hard
to follow and hard to get right insert a call to register the
loopback device directly from net_dev_init(). This guarantes
that the loopback device is the first device registered and
the last network device to go away.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When physical devices are inside of network namespace and that
network namespace terminates we can not make them go away. We
have to keep them and moving them to the initial network namespace
is the best we can do.
For virtual devices left in a network namespace that is exiting
we have no need to preserve them and we now have the infrastructure
that allows us to delete them. So delete virtual devices when we
exit a network namespace. Keeping the necessary user space clean up
after a network namespace exits much more tractable.
Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I noticed a contention on udp_memory_allocated on regular UDP applications.
While tcp_memory_allocated is seldom used, it appears each incoming UDP frame
is currently touching udp_memory_allocated when queued, and when received by
application.
One possible solution is to use sk_mem_reclaim_partial() instead of
sk_mem_reclaim(), so that we keep a small reserve (less than one page)
of memory for each UDP socket.
We did something very similar on TCP side in commit
9993e7d313
([TCP]: Do not purge sk_forward_alloc entirely in tcp_delack_timer())
A more complex solution would need to convert prot->memory_allocated to
use a percpu_counter with batches of 64 or 128 pages.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The changes to deliver hardware accelerated VLAN packets to packet
sockets (commit bc1d0411) caused a warning for non-NAPI drivers.
The __vlan_hwaccel_rx() function is called directly from the drivers
RX function, for non-NAPI drivers that means its still in RX IRQ
context:
[ 27.779463] ------------[ cut here ]------------
[ 27.779509] WARNING: at kernel/softirq.c:136 local_bh_enable+0x37/0x81()
...
[ 27.782520] [<c0264755>] netif_nit_deliver+0x5b/0x75
[ 27.782590] [<c02bba83>] __vlan_hwaccel_rx+0x79/0x162
[ 27.782664] [<f8851c1d>] atl1_intr+0x9a9/0xa7c [atl1]
[ 27.782738] [<c0155b17>] handle_IRQ_event+0x23/0x51
[ 27.782808] [<c015692e>] handle_edge_irq+0xc2/0x102
[ 27.782878] [<c0105fd5>] do_IRQ+0x4d/0x64
Split hardware accelerated VLAN reception into two parts to fix this:
- __vlan_hwaccel_rx just stores the VLAN TCI and performs the VLAN
device lookup, then calls netif_receive_skb()/netif_rx()
- vlan_hwaccel_do_receive(), which is invoked by netif_receive_skb()
in softirq context, performs the real reception and delivery to
packet sockets.
Reported-and-tested-by: Ramon Casellas <ramon.casellas@cttc.es>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
I want to compile out proc_* and sysctl_* handlers totally and
stub them to NULL depending on config options, however usage of &
will prevent this, since taking adress of NULL pointer will break
compilation.
So, drop & in front of every ->proc_handler and every ->strategy
handler, it was never needed in fact.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch gets about 1.25% back on tbench regression.
My change to NAPI for multiqueue support changed the time limit on
network receive processing. Under sustained loads like tbench, this
can cause the receiver to reschedule prematurely.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 04a4bb55bc ("net: add
skb_recycle_check() to enable netdriver skb recycling") added a
method for network drivers to recycle skbuffs, but while use of
this mechanism was documented in the commit message, it should
really have been added as a docbook comment as well -- this
patch does that.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Wireless HW without any dedicated queues for aggregation
do not need the ampdu_queues mechanism present right now
in mac80211. Since mac80211 is still incomplete wrt TX MQ
changes, do not allow aggregation sessions for drivers that
set ampdu_queues.
This is only an interim hack until Intel fixes the requeue issue.
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: Luis Rodriguez <Luis.Rodriguez@Atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
netns ops which are registered with register_pernet_gen_device() are
shutdown strictly before those which are registered with
register_pernet_subsys(). Sometimes this leads to opposite (read: buggy)
shutdown ordering between two modules.
Add register_pernet_gen_subsys()/unregister_pernet_gen_subsys() for modules
which aren't elite enough for entry in struct net, and which can't use
register_pernet_gen_device(). PPTP conntracking module is such one.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Goals are :
1) Optimizing handling of incoming Unicast UDP frames, so that no memory
writes should happen in the fast path.
Note: Multicasts and broadcasts still will need to take a lock,
because doing a full lockless lookup in this case is difficult.
2) No expensive operations in the socket bind/unhash phases :
- No expensive synchronize_rcu() calls.
- No added rcu_head in socket structure, increasing memory needs,
but more important, forcing us to use call_rcu() calls,
that have the bad property of making sockets structure cold.
(rcu grace period between socket freeing and its potential reuse
make this socket being cold in CPU cache).
David did a previous patch using call_rcu() and noticed a 20%
impact on TCP connection rates.
Quoting Cristopher Lameter :
"Right. That results in cacheline cooldown. You'd want to recycle
the object as they are cache hot on a per cpu basis. That is screwed
up by the delayed regular rcu processing. We have seen multiple
regressions due to cacheline cooldown.
The only choice in cacheline hot sensitive areas is to deal with the
complexity that comes with SLAB_DESTROY_BY_RCU or give up on RCU."
- Because udp sockets are allocated from dedicated kmem_cache,
use of SLAB_DESTROY_BY_RCU can help here.
Theory of operation :
---------------------
As the lookup is lockfree (using rcu_read_lock()/rcu_read_unlock()),
special attention must be taken by readers and writers.
Use of SLAB_DESTROY_BY_RCU is tricky too, because a socket can be freed,
reused, inserted in a different chain or in worst case in the same chain
while readers could do lookups in the same time.
In order to avoid loops, a reader must check each socket found in a chain
really belongs to the chain the reader was traversing. If it finds a
mismatch, lookup must start again at the begining. This *restart* loop
is the reason we had to use rdlock for the multicast case, because
we dont want to send same message several times to the same socket.
We use RCU only for fast path.
Thus, /proc/net/udp still takes spinlocks.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
call_rcu() will unconditionally rewrite RCU head anyway.
Applies to
struct neigh_parms
struct neigh_table
struct net
struct cipso_v4_doi
struct in_ifaddr
struct in_device
rt->u.dst
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
when testing the new pktgen module with multiple queues and ixgbe with:
pgset "flag QUEUE_MAP_CPU"
I found that I was getting errors in dmesg like:
pktgen: WARNING: QUEUE_MAP_CPU disabled because CPU count (8) exceeds number
<4>pktgen: WARNING: of tx queues (8) on eth15
you'll note, 8 really doesn't exceed 8.
This patch seemed to fix the logic errors and also the attempts at
limiting line length in printk (which didn't work anyway)
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
To make testing of the network namespace simpler allow
the network namespace code and the sysfs code to be
compiled and run at the same time. To do this only
virtual devices are allowed in the additional network
namespaces and those virtual devices are not placed
in the kobject tree.
Since virtual devices don't actually do anything interesting
hardware wise that needs device management there should
be no loss in keeping them out of the kobject tree and
by implication sysfs. The gain in ease of testing
and code coverage should be significant.
Changelog:
v2: As pointed out by Benjamin Thery it only makes sense to call
device_rename in the initial network namespace for now.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Benjamin Thery <benjamin.thery@bull.net>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This converts pretty much everything to print_mac. There were
a few things that had conflicts which I have just dropped for
now, no harm done.
I've built an allyesconfig with this and looked at the files
that weren't built very carefully, but it's a huge patch.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
My change
commit e2a6b85247
net: Enable TSO if supported by at least one device
didn't do what was intended because the netdev_compute_features
function was designed for conjunctions. So what happened was that
it would simply take the TSO status of the last constituent device.
This patch extends it to support both conjunctions and disjunctions
under the new name of netdev_increment_features.
It also adds a new function netdev_fix_features which does the
sanity checking that usually occurs upon registration. This ensures
that the computation doesn't result in an illegal combination
since this checking is absent when the change is initiated via
ethtool.
The two users of netdev_compute_features have been converted.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
If changename notifier returns an error code, it gets incorrectly
cleared during rollback so the error is never returned to the user.
Found while testing similar code for MTU changes.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some code here depends on CONFIG_KMOD to not try to load
protocol modules or similar, replace by CONFIG_MODULES
where more than just request_module depends on CONFIG_KMOD
and and also use try_then_request_module in ebtables.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Clean up the various different email addresses of mine listed in the code
to a single current and valid address. As Dave says his network merges
for 2.6.28 are now done this seems a good point to send them in where
they won't risk disrupting real changes.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Seems that skb goes into void unless something magic happened
in pskb_expand_head in case of failure.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The unwind loop iterates down to -1 instead of stopping at 0 and ends up
accessing ->frags[-1].
Signed-off-by: Dimitris Michailidis <dm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Conntrack code will use it for
a) removing expectations and helpers when corresponding module is removed, and
b) removing conntracks when L3 protocol conntrack module is removed.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Benjamin Thery tracked down a bug that explains many instances
of the error
unregister_netdevice: waiting for %s to become free. Usage count = %d
It turns out that netdev_run_todo can dead-lock with itself if
a second instance of it is run in a thread that will then free
a reference to the device waited on by the first instance.
The problem is really quite silly. We were trying to create
parallelism where none was required. As netdev_run_todo always
follows a RTNL section, and that todo tasks can only be added
with the RTNL held, by definition you should only need to wait
for the very ones that you've added and be done with it.
There is no need for a second mutex or spinlock.
This is exactly what the following patch does.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
