linux-toradex.git/drivers/net/bonding/bonding.h, branch v3.10.12

bonding: fix igmp_retrans type and two related races

2013-06-13T09:33:37+00:00

First the type of igmp_retrans (which is the actual counter of
igmp_resend parameter) is changed to u8 to be able to store values up
to 255 (as per documentation). There are two races that were hidden
there and which are easy to trigger after the previous fix, the first is
between bond_resend_igmp_join_requests and bond_change_active_slave
where igmp_retrans is set and can be altered by the periodic. The second
race condition is between multiple running instances of the periodic
(upon execution it can be scheduled again for immediate execution which
can cause the counter to go < 0 which in the unsigned case leads to
unnecessary igmp retransmissions).
Since in bond_change_active_slave bond->lock is held for reading and
curr_slave_lock for writing, we use curr_slave_lock for mutual
exclusion. We can't drop them as there're cases where RTNL is not held
when bond_change_active_slave is called. RCU is unlocked in
bond_resend_igmp_join_requests before getting curr_slave_lock since we
don't need it there and it's pointless to delay.
The decrement is moved inside the "if" block because if we decrement
unconditionally there's still a possibility for a race condition although
it is much more difficult to hit (many changes have to happen in
a very short period in order to trigger) which in the case of 3 parallel
running instances of this function and igmp_retrans == 1
(with check bond->igmp_retrans-- > 1) is:
f1 passes, doesn't re-schedule, but decrements - igmp_retrans = 0
f2 then passes, doesn't re-schedule, but decrements - igmp_retrans = 255
f3 does the unnecessary retransmissions.

Signed-off-by: Nikolay Aleksandrov 
Signed-off-by: Jay Vosburgh 
Signed-off-by: David S. Miller

bond: have random dev address by default instead of zeroes

2013-01-30T20:34:00+00:00

Makes more sense to have randomly generated address by default than to
have all zeroes. It also allows user to for example put the bond into
bridge without need to have any slaves in it.

Also note that this changes only behaviour of bonds with no slaves. Once
the first slave device is enslaved, its address will be used (no change
here).

Also, fix dev_assign_type values on the way.

Reported-by: Pavel Šimerda 
Signed-off-by: Jiri Pirko 
Signed-off-by: Jay Vosburgh 
Signed-off-by: David S. Miller

bonding: remove usage of dev->master

2013-01-04T21:31:50+00:00

Benefit from new upper dev list and free bonding from dev->master usage.

Signed-off-by: Jiri Pirko 
Signed-off-by: David S. Miller

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2012-12-13T20:00:02+00:00

Pull trivial branch from Jiri Kosina:
 "Usual stuff -- comment/printk typo fixes, documentation updates, dead
  code elimination."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
  HOWTO: fix double words typo
  x86 mtrr: fix comment typo in mtrr_bp_init
  propagate name change to comments in kernel source
  doc: Update the name of profiling based on sysfs
  treewide: Fix typos in various drivers
  treewide: Fix typos in various Kconfig
  wireless: mwifiex: Fix typo in wireless/mwifiex driver
  messages: i2o: Fix typo in messages/i2o
  scripts/kernel-doc: check that non-void fcts describe their return value
  Kernel-doc: Convention: Use a "Return" section to describe return values
  radeon: Fix typo and copy/paste error in comments
  doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c
  various: Fix spelling of "asynchronous" in comments.
  Fix misspellings of "whether" in comments.
  eisa: Fix spelling of "asynchronous".
  various: Fix spelling of "registered" in comments.
  doc: fix quite a few typos within Documentation
  target: iscsi: fix comment typos in target/iscsi drivers
  treewide: fix typo of "suport" in various comments and Kconfig
  treewide: fix typo of "suppport" in various comments
  ...

bonding: rlb mode of bond should not alter ARP originating via bridge

2012-11-30T17:07:26+00:00

Do not modify or load balance ARP packets passing through balance-alb
mode (wherein the ARP did not originate locally, and arrived via a bridge).

Modifying pass-through ARP replies causes an incorrect MAC address
to be placed into the ARP packet, rendering peers unable to communicate
with the actual destination from which the ARP reply originated.

Load balancing pass-through ARP requests causes an entry to be
created for the peer in the rlb table, and bond_alb_monitor will
occasionally issue ARP updates to all peers in the table instrucing them
as to which MAC address they should communicate with; this occurs when
some event sets rx_ntt.  In the bridged case, however, the MAC address
used for the update would be the MAC of the slave, not the actual source
MAC of the originating destination.  This would render peers unable to
communicate with the destinations beyond the bridge.

Signed-off-by: Zheng Li 
Cc: Jay Vosburgh 
Cc: Andy Gospodarek 
Cc: "David S. Miller" 
Signed-off-by: Jay Vosburgh 
Signed-off-by: David S. Miller

treewide: fix typo of "suport" in various comments and Kconfig

2012-11-19T13:16:09+00:00

Signed-off-by: Masanari Iida 
Signed-off-by: Jiri Kosina

bonding: remove packet cloning in recv_probe()

2012-06-13T01:51:09+00:00

Cloning all packets in input path have a significant cost.

Use skb_header_pointer()/skb_copy_bits() instead of pskb_may_pull() so
that recv_probe handlers (bond_3ad_lacpdu_recv / bond_arp_rcv /
rlb_arp_recv ) dont touch input skb.

bond_handle_frame() can avoid the skb_clone()/dev_kfree_skb()

Signed-off-by: Eric Dumazet 
Cc: Jay Vosburgh 
Cc: Andy Gospodarek 
Cc: Jiri Bohac 
Cc: Nicolas de Pesloüan 
Cc: Maciej Żenczykowski 
Signed-off-by: Jay Vosburgh 
Signed-off-by: David S. Miller

bonding: Fix LACPDU rx_dropped commit.

2012-05-13T19:45:13+00:00

I applied the wrong version of Jiri's bonding fix in commit
13a8e0c8cdb43982372bd6c65fb26839c8fd8ce9 ("bonding: don't increase
rx_dropped after processing LACPDUs")

I applied v3, which introduces warnings I asked him to fix,
instead of v4 which properly takes care of those issues.

This inter-diffs such that the warnings are now gone.

Signed-off-by: David S. Miller

bonding: remove entries for master_ip and vlan_ip and query devices instead

2012-03-23T02:36:17+00:00

The following patch aimed to resolve an issue where secondary, tertiary,
etc. addresses added to bond interfaces could overwrite the
bond->master_ip and vlan_ip values.

        commit 917fbdb32f37e9a93b00bb12ee83532982982df3
        Author: Henrik Saavedra Persson 
        Date:   Wed Nov 23 23:37:15 2011 +0000

            bonding: only use primary address for ARP

That patch was good because it prevented bonds using ARP monitoring from
sending frames with an invalid source IP address.  Unfortunately, it
didn't always work as expected.

When using an ioctl (like ifconfig does) to set the IP address and
netmask, 2 separate ioctls are actually called to set the IP and netmask
if the mask chosen doesn't match the standard mask for that class of
address.  The first ioctl did not have a mask that matched the one in
the primary address and would still cause the device address to be
overwritten.  The second ioctl that was called to set the mask would
then detect as secondary and ignored, but the damage was already done.

This was not an issue when using an application that used netlink
sockets as the setting of IP and netmask came down at once.  The
inconsistent behavior between those two interfaces was something that
needed to be resolved.

While I was thinking about how I wanted to resolve this, Ralf Zeidler
came with a patch that resolved this on a RHEL kernel by keeping a full
shadow of the entries in dev->ifa_list for the bonding device and vlan
devices in the bonding driver.  I didn't like the duplication of the
list as I want to see the 'bonding' struct and code shrink rather than
grow, but liked the general idea.

As the Subject indicates this patch drops the master_ip and vlan_ip
elements from the 'bonding' and 'vlan_entry' structs, respectively.
This can be done because a device's address-list is now traversed to
determine the optimal source IP address for ARP requests and for checks
to see if the bonding device has a particular IP address.  This code
could have all be contained inside the bonding driver, but it made more
sense to me to EXPORT and call inet_confirm_addr since it did exactly
what was needed.

I tested this and a backported patch and everything works as expected.
Ralf also helped with verification of the backported patch.

Thanks to Ralf for all his help on this.

v2: Whitespace and organizational changes based on suggestions from Jay
Vosburgh and Dave Miller.

v3: Fixup incorrect usage of rcu_read_unlock based on Dave Miller's
suggestion.

Signed-off-by: Andy Gospodarek 
CC: Ralf Zeidler 
Signed-off-by: David S. Miller

bonding: eliminate bond_close race conditions

2011-10-30T07:13:14+00:00

This patch resolves two sets of race conditions.

	Mitsuo Hayasaka  reported the
first, as follows:

The bond_close() calls cancel_delayed_work() to cancel delayed works.
It, however, cannot cancel works that were already queued in workqueue.
The bond_open() initializes work->data, and proccess_one_work() refers
get_work_cwq(work)->wq->flags. The get_work_cwq() returns NULL when
work->data has been initialized. Thus, a panic occurs.

	He included a patch that converted the cancel_delayed_work calls
in bond_close to flush_delayed_work_sync, which eliminated the above
problem.

	His patch is incorporated, at least in principle, into this
patch.  In this patch, we use cancel_delayed_work_sync in place of
flush_delayed_work_sync, and also convert bond_uninit in addition to
bond_close.

	This conversion to _sync, however, opens new races between
bond_close and three periodically executing workqueue functions:
bond_mii_monitor, bond_alb_monitor and bond_activebackup_arp_mon.

	The race occurs because bond_close and bond_uninit are always
called with RTNL held, and these workqueue functions may acquire RTNL to
perform failover-related activities.  If bond_close or bond_uninit is
waiting in cancel_delayed_work_sync, deadlock occurs.

	These deadlocks are resolved by having the workqueue functions
acquire RTNL conditionally.  If the rtnl_trylock() fails, the functions
reschedule and return immediately.  For the cases that are attempting to
perform link failover, a delay of 1 is used; for the other cases, the
normal interval is used (as those activities are not as time critical).

	Additionally, the bond_mii_monitor function now stores the delay
in a variable (mimicing the structure of activebackup_arp_mon).

	Lastly, all of the above renders the kill_timers sentinel moot,
and therefore it has been removed.

Tested-by: Mitsuo Hayasaka 
Signed-off-by: Jay Vosburgh 
Signed-off-by: David S. Miller