linux-toradex.git/net/core/netpoll.c, branch v3.16-rc5

netpoll: Use skb_irq_freeable to make zap_completion_queue safe.

2014-04-01T21:53:36+00:00

Replace the test in zap_completion_queue to test when it is safe to
free skbs in hard irq context with skb_irq_freeable ensuring we only
free skbs when it is safe, and removing the possibility of subtle
problems.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

netpoll: Respect NETIF_F_LLTX

2014-03-29T21:58:37+00:00

Stop taking the transmit lock when a network device has specified
NETIF_F_LLTX.

If no locks needed to trasnmit a packet this is the ideal scenario for
netpoll as all packets can be trasnmitted immediately.

Even if some locks are needed in ndo_start_xmit skipping any unnecessary
serialization is desirable for netpoll as it makes it more likely a
debugging packet may be trasnmitted immediately instead of being
deferred until later.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

netpoll: Remove strong unnecessary assumptions about skbs

2014-03-29T21:58:37+00:00

Remove the assumption that the skbs that make it to
netpoll_send_skb_on_dev are allocated with find_skb, such that
skb->users == 1 and nothing is attached that would prevent the skbs from
being freed from hard irq context.

Remove this assumption by replacing __kfree_skb on error paths with
dev_kfree_skb_irq (in hard irq context) and kfree_skb (in process
context).

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

netpoll: Rename netpoll_rx_enable/disable to netpoll_poll_disable/enable

2014-03-29T21:58:37+00:00

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" 
Signed-off-by: David S. Miller

netpoll: Only call ndo_start_xmit from a single place

2014-03-29T21:58:37+00:00

Factor out the code that needs to surround ndo_start_xmit
from netpoll_send_skb_on_dev into netpoll_start_xmit.

It is an unfortunate fact that as the netpoll code has been maintained
the primary call site ndo_start_xmit learned how to handle vlans
and timestamps but the second call of ndo_start_xmit in queue_process
did not.

With the introduction of netpoll_start_xmit this associated logic now
happens at both call sites of ndo_start_xmit and should make it easy
for that to continue into the future.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

netpoll: Remove gfp parameter from __netpoll_setup

2014-03-29T21:58:37+00:00

The gfp parameter was added in:
commit 47be03a28cc6c80e3aa2b3e8ed6d960ff0c5c0af
Author: Amerigo Wang 
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 
    Cc: "David S. Miller" 
    Reported-by: Dan Carpenter 
    Signed-off-by: Eric Dumazet 
    Signed-off-by: Cong Wang 
    Signed-off-by: David S. Miller 

The reason for the gfp parameter was removed in:
commit c4cdef9b7183159c23c7302aaf270d64c549f557
Author: dingtianhong 
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 
    Cc: Jay Vosburgh 
    Cc: Andy Gospodarek 
    Signed-off-by: David S. Miller 

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" 
Signed-off-by: David S. Miller

net/core: Use RCU_INIT_POINTER(x, NULL) in netpoll.c

2014-03-27T04:18:09+00:00

This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL)

The rcu_assign_pointer() ensures that the initialization of a structure
is carried out before storing a pointer to that structure.
And in the case of the NULL pointer, there is no structure to initialize.
So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL)

Signed-off-by: Monam Agarwal 
Signed-off-by: David S. Miller

netpoll: Remove dead packet receive code (CONFIG_NETPOLL_TRAP)

2014-03-17T19:48:12+00:00

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 
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

netpoll: Move all receive processing under CONFIG_NETPOLL_TRAP

2014-03-17T19:48:12+00:00

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" 
Signed-off-by: David S. Miller

netpoll: Consolidate neigh_tx processing in service_neigh_queue

2014-03-17T19:47:23+00:00

Move the bond slave device neigh_tx handling into service_neigh_queue.

In connection with neigh_tx processing remove unnecessary tests of
a NULL netpoll_info.  As the netpoll_poll_dev has already used
and thus verified the existince of the netpoll_info.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller