The netpoll_rx_enable and netpoll_rx_disable functions have always
controlled polling the network drivers transmit and receive queues.
Rename them to netpoll_poll_enable and netpoll_poll_disable to make
their functionality clear.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The gfp parameter was added in:
commit 47be03a28c
Author: Amerigo Wang <amwang@redhat.com>
Date: Fri Aug 10 01:24:37 2012 +0000
netpoll: use GFP_ATOMIC in slave_enable_netpoll() and __netpoll_setup()
slave_enable_netpoll() and __netpoll_setup() may be called
with read_lock() held, so should use GFP_ATOMIC to allocate
memory. Eric suggested to pass gfp flags to __netpoll_setup().
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The reason for the gfp parameter was removed in:
commit c4cdef9b71
Author: dingtianhong <dingtianhong@huawei.com>
Date: Tue Jul 23 15:25:27 2013 +0800
bonding: don't call slave_xxx_netpoll under spinlocks
The slave_xxx_netpoll will call synchronize_rcu_bh(),
so the function may schedule and sleep, it should't be
called under spinlocks.
bond_netpoll_setup() and bond_netpoll_cleanup() are always
protected by rtnl lock, it is no need to take the read lock,
as the slave list couldn't be changed outside rtnl lock.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Cc: Jay Vosburgh <fubar@us.ibm.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Nothing else that calls __netpoll_setup or ndo_netpoll_setup
requires a gfp paramter, so remove the gfp parameter from both
of these functions making the code clearer.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The netpoll packet receive code only becomes active if the netpoll
rx_skb_hook is implemented, and there is not a single implementation
of the netpoll rx_skb_hook in the kernel.
All of the out of tree implementations I have found all call
netpoll_poll which was removed from the kernel in 2011, so this
change should not add any additional breakage.
There are problems with the netpoll packet receive code. __netpoll_rx
does not call dev_kfree_skb_irq or dev_kfree_skb_any in hard irq
context. netpoll_neigh_reply leaks every skb it receives. Reception
of packets does not work successfully on stacked devices (aka bonding,
team, bridge, and vlans).
Given that the netpoll packet receive code is buggy, there are no
out of tree users that will be merged soon, and the code has
not been used for in tree for a decade let's just remove it.
Reverting this commit can server as a starting point for anyone
who wants to resurrect netpoll packet reception support.
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make rx_skb_hook, and rx in struct netpoll depend on
CONFIG_NETPOLL_TRAP Make rx_lock, rx_np, and neigh_tx in struct
netpoll_info depend on CONFIG_NETPOLL_TRAP
Make the functions netpoll_rx_on, netpoll_rx, and netpoll_receive_skb
no-ops when CONFIG_NETPOLL_TRAP is not set.
Only build netpoll_neigh_reply, checksum_udp service_neigh_queue,
pkt_is_ns, and __netpoll_rx when CONFIG_NETPOLL_TRAP is defined.
Add helper functions netpoll_trap_setup, netpoll_trap_setup_info,
netpoll_trap_cleanup, and netpoll_trap_cleanup_info that initialize
and cleanup the struct netpoll and struct netpoll_info receive
specific fields when CONFIG_NETPOLL_TRAP is enabled and do nothing
otherwise.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we no longer need to receive packets to safely drain the
network drivers receive queue move netpoll_trap and netpoll_set_trap
under CONFIG_NETPOLL_TRAP
Making netpoll_trap and netpoll_set_trap noop inline functions
when CONFIG_NETPOLL_TRAP is not set.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change the strategy of netpoll from dropping all packets received
during netpoll_poll_dev to calling napi poll with a budget of 0
(to avoid processing drivers rx queue), and to ignore packets received
with netif_rx (those will safely be placed on the backlog queue).
All of the netpoll supporting drivers have been reviewed to ensure
either thay use netif_rx or that a budget of 0 is supported by their
napi poll routine and that a budget of 0 will not process the drivers
rx queues.
Not dropping packets makes NETPOLL_RX_DROP unnecesary so it is removed.
npinfo->rx_flags is removed as rx_flags with just the NETPOLL_RX_ENABLED
flag becomes just a redundant mirror of list_empty(&npinfo->rx_np).
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a helper netpoll_rx_processing that reports when netpoll has
receive side processing to perform.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Right now skb->data is passed to rx_hook() even if the skb
has not been linearised and without giving rx_hook() a way
to linearise it.
Change the rx_hook() interface and make it accept the skb
and the offset to the UDP payload as arguments. rx_hook() is
also renamed to rx_skb_hook() to ensure that out of the tree
users notice the API change.
In this way any rx_skb_hook() implementation can perform all
the needed operations to properly (and safely) access the
skb data.
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The netpoll_rx_disable() will always return 0, it is no use and looks wordy,
so remove the unnecessary code and get rid of it in _dev_open and _dev_close.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bart Van Assche recently reported a warning to me:
<IRQ> [<ffffffff8103d79f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8103d7fa>] warn_slowpath_null+0x1a/0x20
[<ffffffff814761dd>] mutex_trylock+0x16d/0x180
[<ffffffff813968c9>] netpoll_poll_dev+0x49/0xc30
[<ffffffff8136a2d2>] ? __alloc_skb+0x82/0x2a0
[<ffffffff81397715>] netpoll_send_skb_on_dev+0x265/0x410
[<ffffffff81397c5a>] netpoll_send_udp+0x28a/0x3a0
[<ffffffffa0541843>] ? write_msg+0x53/0x110 [netconsole]
[<ffffffffa05418bf>] write_msg+0xcf/0x110 [netconsole]
[<ffffffff8103eba1>] call_console_drivers.constprop.17+0xa1/0x1c0
[<ffffffff8103fb76>] console_unlock+0x2d6/0x450
[<ffffffff8104011e>] vprintk_emit+0x1ee/0x510
[<ffffffff8146f9f6>] printk+0x4d/0x4f
[<ffffffffa0004f1d>] scsi_print_command+0x7d/0xe0 [scsi_mod]
This resulted from my commit ca99ca14c which introduced a mutex_trylock
operation in a path that could execute in interrupt context. When mutex
debugging is enabled, the above warns the user when we are in fact
exectuting in interrupt context
interrupt context.
After some discussion, It seems that a semaphore is the proper mechanism to use
here. While mutexes are defined to be unusable in interrupt context, no such
condition exists for semaphores (save for the fact that the non blocking api
calls, like up and down_trylock must be used when in irq context).
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Bart Van Assche <bvanassche@acm.org>
CC: Bart Van Assche <bvanassche@acm.org>
CC: David Miller <davem@davemloft.net>
CC: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
__netpoll_rcu_free is used to free netpoll structures when the rtnl_lock is
already held. The mechanism is used to asynchronously call __netpoll_cleanup
outside of the holding of the rtnl_lock, so as to avoid deadlock.
Unfortunately, __netpoll_cleanup modifies pointers (dev->np), which means the
rtnl_lock must be held while calling it. Further, it cannot be held, because
rcu callbacks may be issued in softirq contexts, which cannot sleep.
Fix this by converting the rcu callback to a work queue that is guaranteed to
get scheduled in process context, so that we can hold the rtnl properly while
calling __netpoll_cleanup
Tested successfully by myself.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Cong Wang <amwang@redhat.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ivan Vercera was recently backporting commit
9c13cb8bb4 to a RHEL kernel, and I noticed that,
while this patch protects the tg3 driver from having its ndo_poll_controller
routine called during device initalization, it does nothing for the driver
during shutdown. I.e. it would be entirely possible to have the
ndo_poll_controller method (or subsequently the ndo_poll) routine called for a
driver in the netpoll path on CPU A while in parallel on CPU B, the ndo_close or
ndo_open routine could be called. Given that the two latter routines tend to
initizlize and free many data structures that the former two rely on, the result
can easily be data corruption or various other crashes. Furthermore, it seems
that this is potentially a problem with all net drivers that support netpoll,
and so this should ideally be fixed in a common path.
As Ben H Pointed out to me, we can't preform dev_open/dev_close in atomic
context, so I've come up with this solution. We can use a mutex to sleep in
open/close paths and just do a mutex_trylock in the napi poll path and abandon
the poll attempt if we're locked, as we'll just retry the poll on the next send
anyway.
I've tested this here by flooding netconsole with messages on a system whos nic
driver I modfied to periodically return NETDEV_TX_BUSY, so that the netpoll tx
workqueue would be forced to send frames and poll the device. While this was
going on I rapidly ifdown/up'ed the interface and watched for any problems.
I've not found any.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Ivan Vecera <ivecera@redhat.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Ben Hutchings <bhutchings@solarflare.com>
CC: Francois Romieu <romieu@fr.zoreil.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes several problems in the call path of
netpoll_send_skb_on_dev():
1. Disable IRQ's before calling netpoll_send_skb_on_dev().
2. All the callees of netpoll_send_skb_on_dev() should use
rcu_dereference_bh() to dereference ->npinfo.
3. Rename arp_reply() to netpoll_arp_reply(), the former is too generic.
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In __netpoll_rx(), it dereferences ->npinfo without rcu_dereference_bh(),
this patch fixes it by using the 'npinfo' passed from netpoll_rx()
where it is already dereferenced with rcu_dereference_bh().
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Like the previous patch, slave_disable_netpoll() and __netpoll_cleanup()
may be called with read_lock() held too, so we should make them
non-block, by moving the cleanup and kfree() to call_rcu_bh() callbacks.
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unused symbols waste space.
Commit 0e34e93177
"(netpoll: add generic support for bridge and bonding devices)"
added the symbol more than a year ago with the promise of "future use".
Because it is so far unused, remove it for now.
It can be easily readded if or when it actually needs to be used.
cc: WANG Cong <amwang@redhat.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David 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: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We cannot use rcu_dereference_bh safely in netpoll_rx as we may
be called with IRQs disabled. We could however simply disable
IRQs as that too causes BH to be disabled and is safe in either
case.
Thanks to John Linville for discovering this bug and providing
a patch.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
"netpoll: Use 'bool' for netpoll_rx() return type." missed the case when
CONFIG_NETPOLL is disabled.
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that RCU debugging checks for matching rcu_dereference calls
and rcu_read_lock, we need to use the correct primitives or face
nasty warnings.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
