This patch uses __copy_from_user_nocache on transmit to bypass data
cache for a performance improvement.  skb_add_data_nocache and
skb_copy_to_page_nocache can be called by sendmsg functions to use
this feature, initial support is in tcp_sendmsg.  This functionality is
configurable per device using ethtool.

Presumably, this feature would only be useful when the driver does
not touch the data.  The feature is turned on by default if a device
indicates that it does some form of checksum offload; it is off by
default for devices that do no checksum offload or indicate no checksum
is necessary.  For the former case copy-checksum is probably done
anyway, in the latter case the device is likely loopback in which case
the no cache copy is probably not beneficial.

This patch was tested using 200 instances of netperf TCP_RR with
1400 byte request and one byte reply.  Platform is 16 core AMD x86.

No-cache copy disabled:
   672703 tps, 97.13% utilization
   50/90/99% latency:244.31 484.205 1028.41

No-cache copy enabled:
   702113 tps, 96.16% utilization,
   50/90/99% latency 238.56 467.56 956.955

Using 14000 byte request and response sizes demonstrate the
effects more dramatically:

No-cache copy disabled:
   79571 tps, 34.34 %utlization
   50/90/95% latency 1584.46 2319.59 5001.76

No-cache copy enabled:
   83856 tps, 34.81% utilization
   50/90/95% latency 2508.42 2622.62 2735.88

Note especially the effect on latency tail (95th percentile).

This seems to provide a nice performance improvement and is
consistent in the tests I ran.  Presumably, this would provide
the greatest benfits in the presence of an application workload
stressing the cache and a lot of transmit data happening.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This prevents possible race between bond_enslave and bond_handle_frame
as reported by Nicolas by moving rx_handler register/unregister.
slave->bond is added to hold pointer to master bonding sructure. That
way dev->master is no longer used in bond_handler_frame.
Also, this removes "BUG: scheduling while atomic" message
Reported-by: NNicolas de Pesloüan <nicolas.2p.debian@gmail.com>
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NAndy Gospodarek <andy@greyhouse.net>
Tested-by: NNicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NNicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Only slaves that are up should transmit netpoll frames, so there is no
need to check to see if a slave is up before enabling netpoll on it.
This resolves a reported failure on active-backup bonds where a slave
interface is down when netpoll was enabled.
Signed-off-by: NAndy Gospodarek <andy@greyhouse.net>
Tested-by: NWANG Cong <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch allows rx_handlers to better signalize what to do next to
it's caller. That makes skb->deliver_no_wcard no longer needed.

kernel-doc for rx_handler_result is taken from Nicolas' patch.
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Reviewed-by: NNicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since bond-related code was moved from net/core/dev.c into bonding,
IFF_SLAVE_INACTIVE is no longer needed. Replace is with flag "inactive"
stored in slave structure
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Reviewed-by: NNicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

transfers slave->state into slave->backup (that it's going to transfer
into bitfield. Introduce wrapper inlines to do the work with it.
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Reviewed-by: NNicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now when bond-related code is moved from net/core/dev.c into bonding
code, multiple priv_flags are not needed anymore. So let them rot.
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Reviewed-by: NNicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Register slave pointer as rx_handler data. That would eventually prevent
need to loop over slave devices to find the right slave.

Use synchronize_net to ensure that bond_handle_frame does not get slave
structure freed when working with that.
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Reviewed-by: NNicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Bringing up a bond interface with all network cables disconnected
does not properly set the interface as DOWN because the call to
netif_carrier_off occurs too early in bond_init.  The call needs
to occur after register_netdevice has set dev->reg_state to
NETREG_REGISTERED, so that netif_carrier_off will trigger the
call to linkwatch_fire_event.
Signed-off-by: NPhil Oester <kernel@linuxace.com>
Signed-off-by: NAndy Gospodarek <andy@greyhouse.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When packets come in from a device with >= 16 receive queues
headed out a bonding interface, syslog gets filled with this:

    kernel: bond0 selects TX queue 16, but real number of TX queues is 16

because queue_mapping is offset by 1.  Adjust return value
to account for the offset.

This is a revision of my earlier patch (which did not use the
skb_rx_queue_* helpers - thanks to Ben for the suggestion).
Andy submitted a similar patch which emits a pr_warning on
invalid queue selection, but I believe the log spew is
not useful.  We can revisit that question in the future,
but in the interim I believe fixing the core problem is
worthwhile.
Signed-off-by: NPhil Oester <kernel@linuxace.com>
Signed-off-by: NAndy Gospodarek <andy@greyhouse.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The idea here is this minimizes the number of places one has to edit
in order to make changes to how flows are defined and used.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

V2: Move #ifdef CONFIG_PROC_FS into bonding.h, as suggested by David.

bond_main.c is bloating, separate the procfs code out,
move them to bond_procfs.c
Signed-off-by: NWANG Cong <amwang@redhat.com>
Reviewed-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NAndy Gospodarek <andy@greyhouse.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When there is a ptype handler holding a clone of this skb, whose
destination MAC addresse is overwritten, the owner of this handler may
get a corrupted packet.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These two functions are only used when net poll controller is enabled.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Instead of on the stack.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch converts bonding to use rx_handler. Results in cleaner
__netif_receive_skb() with much less exceptions needed. Also
bond-specific work is moved into bond code.

Did performance test using pktgen and counting incoming packets by
iptables. No regression noted.
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Reviewed-by: NNicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

V4: rebase to net-next-2.6

This patch removes the flag IFF_IN_NETPOLL, we don't need it any more since
we have netpoll_tx_running() now.
Signed-off-by: NWANG Cong <amwang@redhat.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

V4: rebase to net-next-2.6
V3: remove an useless #ifdef.

This patch unifies the netpoll code in bonding with netpoll code in bridge,
thanks to Herbert that code is much cleaner now.
Signed-off-by: NWANG Cong <amwang@redhat.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

allow enslaving/releasing using netlink interface
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

dev->master is now tightly connected to bonding driver. This patch makes
this pointer more general and ready to be used by others.

 - netdev_set_master() - bond specifics moved to new function
   netdev_set_bond_master()
 - introduced netif_is_bond_slave() to check if device is a bonding slave
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reduce printk() levels to KERN_INFO in netdev_fix_features() as this will
be used by ethtool and might spam dmesg unnecessarily.

This converts the function to use netdev_info() instead of plain printk().

As a side effect, bonding and bridge devices will now log dropped features
on every slave device change.
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Quoting Ben Hutchings: we presumably won't be defining features that
can only be enabled on 64-bit architectures.

Occurences found by `grep -r` on net/, drivers/net, include/

[ Move features and vlan_features next to each other in
  struct netdev, as per Eric Dumazet's suggestion -DaveM ]
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Recently reported oops:

kernel BUG at net/core/skbuff.c:813!
invalid opcode: 0000 [#1] SMP
last sysfs file: /sys/devices/virtual/net/bond0/broadcast
CPU 8
Modules linked in: sit tunnel4 cpufreq_ondemand acpi_cpufreq freq_table bonding
ipv6 dm_mirror dm_region_hash dm_log cdc_ether usbnet mii serio_raw i2c_i801
i2c_core iTCO_wdt iTCO_vendor_support shpchp ioatdma i7core_edac edac_core bnx2
ixgbe dca mdio sg ext4 mbcache jbd2 sd_mod crc_t10dif mptsas mptscsih mptbase
scsi_transport_sas dm_mod [last unloaded: microcode]

Modules linked in: sit tunnel4 cpufreq_ondemand acpi_cpufreq freq_table bonding
ipv6 dm_mirror dm_region_hash dm_log cdc_ether usbnet mii serio_raw i2c_i801
i2c_core iTCO_wdt iTCO_vendor_support shpchp ioatdma i7core_edac edac_core bnx2
ixgbe dca mdio sg ext4 mbcache jbd2 sd_mod crc_t10dif mptsas mptscsih mptbase
scsi_transport_sas dm_mod [last unloaded: microcode]
Pid: 0, comm: swapper Not tainted 2.6.32-71.el6.x86_64 #1 BladeCenter HS22
-[7870AC1]-
RIP: 0010:[<ffffffff81405b16>]  [<ffffffff81405b16>]
pskb_expand_head+0x36/0x1e0
RSP: 0018:ffff880028303b70  EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff880c6458ec80 RCX: 0000000000000020
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880c6458ec80
RBP: ffff880028303bc0 R08: ffffffff818a6180 R09: ffff880c6458ed64
R10: ffff880c622b36c0 R11: 0000000000000400 R12: 0000000000000000
R13: 0000000000000180 R14: ffff880c622b3000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff880028300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 00000038653452a4 CR3: 0000000001001000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 0, threadinfo ffff8806649c2000, task ffff880c64f16ab0)
Stack:
 ffff880028303bc0 ffffffff8104fff9 000000000000001c 0000000100000000
<0> ffff880000047d80 ffff880c6458ec80 000000000000001c ffff880c6223da00
<0> ffff880c622b3000 0000000000000000 ffff880028303c10 ffffffff81407f7a
Call Trace:
<IRQ>
 [<ffffffff8104fff9>] ? __wake_up_common+0x59/0x90
 [<ffffffff81407f7a>] __pskb_pull_tail+0x2aa/0x360
 [<ffffffffa0244530>] bond_arp_rcv+0x2c0/0x2e0 [bonding]
 [<ffffffff814a0857>] ? packet_rcv+0x377/0x440
 [<ffffffff8140f21b>] netif_receive_skb+0x2db/0x670
 [<ffffffff8140f788>] napi_skb_finish+0x58/0x70
 [<ffffffff8140fc89>] napi_gro_receive+0x39/0x50
 [<ffffffffa01286eb>] ixgbe_clean_rx_irq+0x35b/0x900 [ixgbe]
 [<ffffffffa01290f6>] ixgbe_clean_rxtx_many+0x136/0x240 [ixgbe]
 [<ffffffff8140fe53>] net_rx_action+0x103/0x210
 [<ffffffff81073bd7>] __do_softirq+0xb7/0x1e0
 [<ffffffff810d8740>] ? handle_IRQ_event+0x60/0x170
 [<ffffffff810142cc>] call_softirq+0x1c/0x30
 [<ffffffff81015f35>] do_softirq+0x65/0xa0
 [<ffffffff810739d5>] irq_exit+0x85/0x90
 [<ffffffff814cf915>] do_IRQ+0x75/0xf0
 [<ffffffff81013ad3>] ret_from_intr+0x0/0x11
 <EOI>
 [<ffffffff8101bc01>] ? mwait_idle+0x71/0xd0
 [<ffffffff814cd80a>] ? atomic_notifier_call_chain+0x1a/0x20
 [<ffffffff81011e96>] cpu_idle+0xb6/0x110
 [<ffffffff814c17c8>] start_secondary+0x1fc/0x23f

Resulted from bonding driver registering packet handlers via dev_add_pack and
then trying to call pskb_may_pull. If another packet handler (like for AF_PACKET
sockets) gets called first, the delivered skb will have a user count > 1, which
causes pskb_may_pull to BUG halt when it does its skb_shared check.  Fix this by
calling skb_share_check prior to the may_pull call sites in the bonding driver
to clone the skb when needed.  Tested by myself and the reported successfully.

Signed-off-by: Neil Horman
CC: Andy Gospodarek <andy@greyhouse.net>
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NAndy Gospodarek <andy@greyhouse.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

bond_change_active_slave() may be called when a slave is added, even
if the bond has not been brought up yet.  It may then attempt to send
packets, and further it may use mcast_work which is uninitialised
before the bond is brought up.  Add the necessary checks for
netif_running(bond->dev).
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A bond may have a mixture of slave devices with and without hardware
VLAN tag insertion capability.  Therefore it always claims this
capability and performs software VLAN tag insertion if the slave does
not.

Since commit 7b9c6090, this has
also been done by dev_hard_start_xmit().  The result is that VLAN-
tagged skbs are now double-tagged when transmitted through slave
devices without hardware VLAN tag insertion!

Remove the now-redundant logic from bond_dev_queue_xmit().
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Reviewed-by: NJesse Gross <jesse@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch provides the debugfs facility to the bonding driver.
The "bonding" directory is created in the debugfs root and directories of
each bonding interface (like bond0, bond1...) are created in that.

 # mount -t debugfs none /sys/kernel/debug

 # ls /sys/kernel/debug/bonding
 bond0  bond1
Signed-off-by: NTaku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A while back I made some changes to enable netpoll in the bonding driver.  Among
them was a per-cpu flag that indicated we were in a path that held locks which
could cause the netpoll path to block in during tx, and as such the tx path
should queue the frame for later use.  This appears to have given rise to a
regression.  If one of those paths on which we hold the per-cpu flag yields the
cpu, its possible for us to come back on a different cpu, leading to us clearing
a different flag than we set.  This results in odd netpoll drops, and BUG
backtraces appearing in the log, as we check to make sure that we only clear set
bits, and only set clear bits.  I had though briefly about changing the
offending paths so that they wouldn't sleep, but looking at my origional work
more closely, it doesn't appear that a per-cpu flag is warranted.  We alrady
gate the checking of this flag on IFF_IN_NETPOLL, so we don't hit this in the
normal tx case anyway.  And practically speaking, the normal use case for
netpoll is to only have one client anyway, so we're not going to erroneously
queue netpoll frames when its actually safe to do so.  As such, lets just
convert that per-cpu flag to an atomic counter.  It fixes the rescheduling bugs,
is equivalent from a performance perspective and actually eliminates some code
in the process.

Tested by the reporter and myself, successfully
Reported-by: NLiang Zheng <lzheng@redhat.com>
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: David S. Miller <davem@davemloft.net>
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Restore the check for an unassigned mac address before adopting the
first slaves as it's own. The change in behavior was introduced by:

commit c20811a7
Author: Jiri Pirko <jpirko@redhat.com>

    bonding: move dev_addr cpy to bond_enslave
Signed-off-by: NDavid Strand <dpstrand@gmail.com>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Instead of iterating in_dev->mc_list from bonding driver, its better
to call a helper function provided by igmp.c
Details of implementation (locking) are private to igmp code.

ip_mc_rejoin_group(struct ip_mc_list *im) becomes
ip_mc_rejoin_groups(struct in_device *in_dev);
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RCU conversion in IGMP code done in net-next-2.6 raised a race in
__bond_resend_igmp_join_requests().

It iterates in_dev->mc_list without appropriate protection (RTNL, or
read_lock on in_dev->mc_list_lock).

Another cpu might delete an entry while we use it and trigger a fault.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

bond_info_seq_start() uses a read_lock(&dev_base_lock) to make sure
device doesn’t disappear. Same goal can be achieved using RCU.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix lockdep warning:
[   52.991402] ======================================================
[   52.991511] [ INFO: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected ]
[   52.991569] 2.6.36-04573-g4b60626-dirty #65
[   52.991622] ------------------------------------------------------
[   52.991696] ip/4842 [HC0[0]:SC0[4]:HE1:SE0] is trying to acquire:
[   52.991758]  (&bond->lock){++++..}, at: [<efe4d300>] bond_set_multicast_list+0x60/0x2c0 [bonding]
[   52.991966]
[   52.991967] and this task is already holding:
[   52.992008]  (&bonding_netdev_addr_lock_key){+.....}, at: [<c04e5530>] dev_mc_sync+0x50/0xa0
[   52.992008] which would create a new lock dependency:
[   52.992008]  (&bonding_netdev_addr_lock_key){+.....} -> (&bond->lock){++++..}
[   52.992008]
[   52.992008] but this new dependency connects a SOFTIRQ-irq-safe lock:
[   52.992008]  (&(&mc->mca_lock)->rlock){+.-...}
[   52.992008] ... which became SOFTIRQ-irq-safe at:
[   52.992008]   [<c0272beb>] __lock_acquire+0x96b/0x1960
[   52.992008]   [<c027415e>] lock_acquire+0x7e/0xf0
[   52.992008]   [<c05f356d>] _raw_spin_lock_bh+0x3d/0x50
[   52.992008]   [<c0584e40>] mld_ifc_timer_expire+0xf0/0x280
[   52.992008]   [<c024cee6>] run_timer_softirq+0x146/0x310
[   52.992008]   [<c024591d>] __do_softirq+0xad/0x1c0
[   52.992008]
[   52.992008] to a SOFTIRQ-irq-unsafe lock:
[   52.992008]  (&bond->lock){++++..}
[   52.992008] ... which became SOFTIRQ-irq-unsafe at:
[   52.992008] ...  [<c0272c3b>] __lock_acquire+0x9bb/0x1960
[   52.992008]   [<c027415e>] lock_acquire+0x7e/0xf0
[   52.992008]   [<c05f36b8>] _raw_write_lock+0x38/0x50
[   52.992008]   [<efe4cbe4>] bond_vlan_rx_register+0x24/0x70 [bonding]
[   52.992008]   [<c0598010>] register_vlan_dev+0xc0/0x280
[   52.992008]   [<c0599f3a>] vlan_newlink+0xaa/0xd0
[   52.992008]   [<c04ed4b4>] rtnl_newlink+0x404/0x490
[   52.992008]   [<c04ece35>] rtnetlink_rcv_msg+0x1e5/0x220
[   52.992008]   [<c050424e>] netlink_rcv_skb+0x8e/0xb0
[   52.992008]   [<c04ecbac>] rtnetlink_rcv+0x1c/0x30
[   52.992008]   [<c0503bfb>] netlink_unicast+0x24b/0x290
[   52.992008]   [<c0503e37>] netlink_sendmsg+0x1f7/0x310
[   52.992008]   [<c04cd41c>] sock_sendmsg+0xac/0xe0
[   52.992008]   [<c04ceb80>] sys_sendmsg+0x130/0x230
[   52.992008]   [<c04cf04e>] sys_socketcall+0xde/0x280
[   52.992008]   [<c0202d10>] sysenter_do_call+0x12/0x36
[   52.992008]
[   52.992008] other info that might help us debug this:
...
[ Full info at netdev: Wed, 27 Oct 2010 12:24:30 +0200
  Subject: [BUG net-2.6 vlan/bonding] lockdep splats ]

Use BH variant of write_lock(&bond->lock) (as elsewhere in bond_main)
to prevent this dependency.

Fixes commit f35188fa [v2.6.36]
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Tested-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Jay Vosburgh <fubar@us.ibm.com>

Only used in main file.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Acked-by: NAndy Gospodarek <andy@greyhouse.net>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Acked-by: NFlavio Leitner <fleitner@redhat.com>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some recent testing in netpoll with bonding showed this backtrace

 ------------[ cut here ]------------
 kernel BUG at drivers/net/bonding/bonding.h:134!
 invalid opcode: 0000 [#1] SMP
 last sysfs file: /sys/devices/pci0000:00/0000:00:1d.2/usb7/devnum
 CPU 0
 Pid: 1876, comm: rmmod Not tainted 2.6.36-rc3+ #10 D26928/
 RIP: 0010:[<ffffffffa0514ba4>]  [<ffffffffa0514ba4>] bond_uninit+0x6f4/0x7a0
 RSP: 0018:ffff88003b1b5d58  EFLAGS: 00010296
 RAX: ffff88003b9b6200 RBX: ffff8800373e8e00 RCX: 00000000000f4240
 RDX: 00000000ffffffff RSI: 0000000000000286 RDI: 0000000000000286
 RBP: ffff88003b1b5dc8 R08: 0000000000000000 R09: 00000001af7de920
 R10: 0000000000000000 R11: ffff880002495e98 R12: ffff880037922700
 R13: ffff880038c31000 R14: ffff880037922730 R15: 0000000000000286
 FS:  00007f90e6d72700(0000) GS:ffff880002400000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 000000346f0d9ad0 CR3: 000000003b263000 CR4: 00000000000006f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Process rmmod (pid: 1876, threadinfo ffff88003b1b4000, task ffff88003b36aa80)
 Stack:
 00000000ffffffff ffff88003b1b5d7a ffff8800379221e8 ffff880037922000
 <0> ffff88003b1b5dc8 ffffffff813eb5fb ffff88003b1b5da8 0000000031b177a3
 <0> ffff88003b1b5da8 ffff880037922000 ffff88003b1b5e48 ffff88003b1b5e48
 Call Trace:
 [<ffffffff813eb5fb>] ? rtmsg_ifinfo+0xcb/0xf0
 [<ffffffff813daad8>] rollback_registered_many+0x168/0x280
 [<ffffffff813dac09>] unregister_netdevice_many+0x19/0x80
 [<ffffffff813e97b3>] __rtnl_kill_links+0x63/0x90
 [<ffffffff813e980b>] __rtnl_link_unregister+0x2b/0x60
 [<ffffffff813e9bde>] rtnl_link_unregister+0x1e/0x30
 [<ffffffffa052124b>] bonding_exit+0x37/0x51 [bonding]
 [<ffffffff81098b2e>] sys_delete_module+0x19e/0x270
 [<ffffffff810bb2b2>] ? audit_syscall_entry+0x252/0x280
 [<ffffffff8100b0b2>] system_call_fastpath+0x16/0x1b
 RIP  [<ffffffffa0514ba4>] bond_uninit+0x6f4/0x7a0 [bonding]
 RSP <ffff88003b1b5d58>
 ---[ end trace 1395ad691cea24d1 ]---

It occurs because of my recent netpoll blocking patches, which I added to avoid
recursive deadlock in the bonding driver.  It relies on some per cpu bits, but
the shutdown path forces some rescheduling as we cancel workqueues for the
driver and wait for some device refcounts.  If after the forced reschedule, we
wind up on a different cpu we trigger the bughalt in unblock_netpoll_tx.

The fix is to remove the netpoll block/unblock calls from bond_release_all.
This is safe to do because bond_uninit, which is called via ndo_uninit in
rollback_registered_many, doesn't occur until we send a NETDEV_UNREGISTER event,
which triggers netconsole to remove us as a netpoll client, so we are guaranteed
not to recurse into our own tx path here.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Reviewed-by: NWANG Cong <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With the inclusion of previous fixup patches, netpoll over bonding apears to
work reliably with failover conditions.  This reverts Gospos previous commit
c22d7ac8, and allows access again to the netpoll
functionality in the bonding driver.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The monitoring paths in the bonding driver take write locks that are shared by
the tx path.  If netconsole is in use, these paths can call printk which puts us
in the netpoll tx path, which, if netconsole is attached to the bonding driver,
result in deadlock (the xmit_lock guards are useless in netpoll_send_skb, as the
monitor paths in the bonding driver don't claim the xmit_lock, nor should they).
The solution is to use a per cpu flag internal to the driver to indicate when a
cpu is holding the lock in a path that might recusrse into the tx path for the
driver via netconsole.  By checking this flag on transmit, we can defer the
sending of the netconsole frames until a later time using the retransmit feature
of netpoll_send_skb that is triggered on the return code NETDEV_TX_BUSY.  I've
tested this and am able to transmit via netconsole while causing failover
conditions on the bond slave links.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The bonding driver currently modifies the netpoll structure in its xmit path
while sending frames from netpoll.  This is racy, as other cpus can access the
netpoll structure in parallel. Since the bonding driver points np->dev to a
slave device, other cpus can inadvertently attempt to send data directly to
slave devices, leading to improper locking with the bonding master, lost frames,
and deadlocks.  This patch fixes that up.

This patch also removes the real_dev pointer from the netpoll structure as that
data is really only used by bonding in the poll_controller, and we can emulate
its behavior by check each slave for IS_UP.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Effect:
 Slave Interface: eth5
 MII Status: up
 Speed: 10000 Mbps
 Duplex: full
 Link Failure Count: 0
 Permanent HW addr: XX:XX:XX:XX:XX:XX
 Slave queue ID: 0
Signed-off-by: NKrzysztof Piotr Oledzki <ole@ans.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>