TIPC currently handles two media specific addresses: Ethernet MAC
addresses and InfiniBand addresses. Those are kept in three different
formats:

1) A "raw" format as obtained from the device. This format is known
   only by the media specific adapter code in eth_media.c and
   ib_media.c.
2) A "generic" internal format, in the form of struct tipc_media_addr,
   which can be referenced and passed around by the generic media-
   unaware code.
3) A serialized version of the latter, to be conveyed in neighbor
   discovery messages.

Conversion between the three formats can only be done by the media
specific code, so we have function pointers for this purpose in
struct tipc_media. Here, the media adapters can install their own
conversion functions at startup.

We now introduce a new such function, 'raw2addr()', whose purpose
is to convert from format 1 to format 2 above. We also try to as far
as possible uniform commenting, variable names and usage of these
functions, with the purpose of making them more comprehensible.

We can now also remove the function tipc_l2_media_addr_set(), whose
job is done better by the new function.

Finally, we expand the field for serialized addresses (format 3)
in discovery messages from 20 to 32 bytes. This is permitted
according to the spec, and reduces the risk of problems when we
add new media in the future.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function tipc_link_frag_rcv() is in reality a re-entrant generic
message reassemby function that has nothing in particular to do with
the link, where it is defined now. This becomes obvious when we see
the need to call the function from other places in the code.

In this commit rename it to tipc_buf_append() and move it to the file
msg.c. We also simplify its signature by moving the tail pointer to
the control block of the head buffer, hence making the head buffer
self-contained.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The message reassembly function does not update the 'len' and 'data_len'
fields of the head skbuff correctly when fragments are chained to it.
This may sometimes lead to obsure errors, such as fragment reordering
when we receive fragments which are cloned buffers.

This commit fixes this, by ensuring that the two fields are updated
correctly.
Suggested-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the current code, all incoming LINK_PROTOCOL messages, irrespective
of type, nudge the "last message received" checkpoint, informing the
link state machine that a message was received from the peer since last
supervision timeout event. This inhibits the link from starting probing
the peer unnecessarily.

However, not only STATE messages are recorded as legitimate incoming
traffic this way, but even RESET and ACTIVATE messages, which in
reality are there to inform the link that the peer endpoint has been
reset. At the same time, some RESET messages may be dropped instead
of causing a link reset. This happens when the link endpoint thinks
it is fully up and working, and the session number of the RESET is
lower than or equal to the current link session. In such cases the
RESET is perceived as a delayed remnant from an earlier session, or
the current one, and dropped.

Now, if a TIPC module is removed and then immediately reinserted, e.g.
when using a script, RESET messages may arrive at the peer link endpoint
before this one has had time to discover the failure. The RESET may be
dropped because of the session number, but only after it has been
recorded as a legitimate traffic event. Hence, the receiving link will
not start probing, and not discover that the peer endpoint is down, at
the same time ignoring the periodic RESET messages coming from that
endpoint. We have ended up in a stale state where a failed link cannot
be re-established.

In this commit, we remedy this by nudging the checkpoint only for
received STATE messages, not for RESET or ACTIVATE messages.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function net/core/sock.c::__release_sock() runs a tight loop
to move buffers from the socket backlog queue to the receive queue.

As a security measure, sk_backlog.len of the receiving socket
is not set to zero until after the loop is finished, i.e., until
the whole backlog queue has been transferred to the receive queue.
During this transfer, the data that has already been moved is counted
both in the backlog queue and the receive queue, hence giving an
incorrect picture of the available queue space for new arriving buffers.

This leads to unnecessary rejection of buffers by sk_add_backlog(),
which in TIPC leads to unnecessarily broken connections.

In this commit, we compensate for this double accounting by adding
a counter that keeps track of it. The function socket.c::backlog_rcv()
receives buffers one by one from __release_sock(), and adds them to the
socket receive queue. If the transfer is successful, it increases a new
atomic counter 'tipc_sock::dupl_rcvcnt' with 'truesize' of the
transferred buffer. If a new buffer arrives during this transfer and
finds the socket busy (owned), we attempt to add it to the backlog.
However, when sk_add_backlog() is called, we adjust the 'limit'
parameter with the value of the new counter, so that the risk of
inadvertent rejection is eliminated.

It should be noted that this change does not invalidate the original
purpose of zeroing 'sk_backlog.len' after the full transfer. We set an
upper limit for dupl_rcvcnt, so that if a 'wild' sender (i.e., one that
doesn't respect the send window) keeps pumping in buffers to
sk_add_backlog(), he will eventually reach an upper limit,
(2 x TIPC_CONN_OVERLOAD_LIMIT). After that, no messages can be added
to the backlog, and the connection will be broken. Ordinary, well-
behaved senders will never reach this buffer limit at all.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Memory overhead when allocating big buffers for data transfer may
be quite significant. E.g., truesize of a 64 KB buffer turns out
to be 132 KB, 2 x the requested size.

This invalidates the "worst case" calculation we have been
using to determine the default socket receive buffer limit,
which is based on the assumption that 1024x64KB = 67MB buffers
may be queued up on a socket.

Since TIPC connections cannot survive hitting the buffer limit,
we have to compensate for this overhead.

We do that in this commit by dividing the fix connection flow
control window from 1024 (2*512) messages to 512 (2*256). Since
older version nodes send out acks at 512 message intervals,
compatibility with such nodes is guaranteed, although performance
may be non-optimal in such cases.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When using mark-based routing, sockets returned from accept()
may need to be marked differently depending on the incoming
connection request.

This is the case, for example, if different socket marks identify
different networks: a listening socket may want to accept
connections from all networks, but each connection should be
marked with the network that the request came in on, so that
subsequent packets are sent on the correct network.

This patch adds a sysctl to mark TCP sockets based on the fwmark
of the incoming SYN packet. If enabled, and an unmarked socket
receives a SYN, then the SYN packet's fwmark is written to the
connection's inet_request_sock, and later written back to the
accepted socket when the connection is established.  If the
socket already has a nonzero mark, then the behaviour is the same
as it is today, i.e., the listening socket's fwmark is used.

Black-box tested using user-mode linux:

- IPv4/IPv6 SYN+ACK, FIN, etc. packets are routed based on the
  mark of the incoming SYN packet.
- The socket returned by accept() is marked with the mark of the
  incoming SYN packet.
- Tested with syncookies=1 and syncookies=2.
Signed-off-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, routing lookups used for Path PMTU Discovery in
absence of a socket or on unmarked sockets use a mark of 0.
This causes PMTUD not to work when using routing based on
netfilter fwmark mangling and fwmark ip rules, such as:

  iptables -j MARK --set-mark 17
  ip rule add fwmark 17 lookup 100

This patch causes these route lookups to use the fwmark from the
received ICMP error when the fwmark_reflect sysctl is enabled.
This allows the administrator to make PMTUD work by configuring
appropriate fwmark rules to mark the inbound ICMP packets.

Black-box tested using user-mode linux by pointing different
fwmarks at routing tables egressing on different interfaces, and
using iptables mangling to mark packets inbound on each interface
with the interface's fwmark. ICMPv4 and ICMPv6 PMTU discovery
work as expected when mark reflection is enabled and fail when
it is disabled.
Signed-off-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Kernel-originated IP packets that have no user socket associated
with them (e.g., ICMP errors and echo replies, TCP RSTs, etc.)
are emitted with a mark of zero. Add a sysctl to make them have
the same mark as the packet they are replying to.

This allows an administrator that wishes to do so to use
mark-based routing, firewalling, etc. for these replies by
marking the original packets inbound.

Tested using user-mode linux:
 - ICMP/ICMPv6 echo replies and errors.
 - TCP RST packets (IPv4 and IPv6).
Signed-off-by: NLorenzo Colitti <lorenzo@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After all the preparatory works, supporting IPv6 in Fast Open is now easy.
We pretty much just mirror v4 code. The only difference is how we
generate the Fast Open cookie for IPv6 sockets. Since Fast Open cookie
is 128 bits and we use AES 128, we use CBC-MAC to encrypt both the
source and destination IPv6 addresses since the cookie is a MAC tag.
Signed-off-by: NDaniel Lee <longinus00@gmail.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NJerry Chu <hkchu@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If a fast open socket is already accepted by the user, it should
be treated like a connected socket to record the ICMP error in
sk_softerr, so the user can fetch it. Do that in both tcp_v4_err
and tcp_v6_err.

Also refactor the sequence window check to improve readability
(e.g., there were two local variables named 'req').
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDaniel Lee <longinus00@gmail.com>
Signed-off-by: NJerry Chu <hkchu@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To avoid large code duplication in IPv6, we need to first simplify
the complicate SYN-ACK sending code in tcp_v4_conn_request().

To use tcp_v4(6)_send_synack() to send all SYN-ACKs, we need to
initialize the mini socket's receive window before trying to
create the child socket and/or building the SYN-ACK packet. So we move
that initialization from tcp_make_synack() to tcp_v4_conn_request()
as a new function tcp_openreq_init_req_rwin().

After this refactoring the SYN-ACK sending code is simpler and easier
to implement Fast Open for IPv6.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDaniel Lee <longinus00@gmail.com>
Signed-off-by: NJerry Chu <hkchu@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Consolidate various cookie checking and generation code to simplify
the fast open processing. The main goal is to reduce code duplication
in tcp_v4_conn_request() for IPv6 support.

Removes two experimental sysctl flags TFO_SERVER_ALWAYS and
TFO_SERVER_COOKIE_NOT_CHKD used primarily for developmental debugging
purposes.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDaniel Lee <longinus00@gmail.com>
Signed-off-by: NJerry Chu <hkchu@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move common TFO functions that will be used by both v4 and v6
to tcp_fastopen.c. Create a helper tcp_fastopen_queue_check().
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDaniel Lee <longinus00@gmail.com>
Signed-off-by: NJerry Chu <hkchu@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net: get rid of SET_ETHTOOL_OPS

Dave Miller mentioned he'd like to see SET_ETHTOOL_OPS gone.
This does that.

Mostly done via coccinelle script:
@@
struct ethtool_ops *ops;
struct net_device *dev;
@@
-       SET_ETHTOOL_OPS(dev, ops);
+       dev->ethtool_ops = ops;

Compile tested only, but I'd seriously wonder if this broke anything.
Suggested-by: NDave Miller <davem@davemloft.net>
Signed-off-by: NWilfried Klaebe <w-lkml@lebenslange-mailadresse.de>
Acked-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sk_unattached_filter_create() will copy the filter's instructions so we
don't need to have the master copy hanging around after initialization.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Do not collide with the x86-64 PTRACE user API namespace.

net/core/filter.c:57:0: warning: "R8" redefined [enabled by default]
arch/x86/include/uapi/asm/ptrace-abi.h:38:0: note: this is the location of the previous definition

Fix by adding a BPF_ prefix to the register macros.
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When I use the following command, eth0 cannot send any packets.
 #tc qdisc add dev eth0 root handle 1: hhf limit 1

Because qlen need be smaller than limit, all packets were dropped.
Fix this by qlen *<=* limit.
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The __vlan_find_dev_deep should always called in RCU, according
David's suggestion, rename to __vlan_find_dev_deep_rcu looks more
reasonable.
Signed-off-by: NDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As suggested by several people, rename local_df to ignore_df,
since it means "ignore df bit if it is set".

Cc: Maciej Żenczykowski <maze@google.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NMaciej Żenczykowski <maze@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

the parameter rt will be assigned to c.arg in function fib6_clean_tree(),
but function fib6_prune_clone() doesn't use c.arg, so we can remove it
safely.
Signed-off-by: NDuan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce BPF helper macros to define instructions
(similar to old BPF_STMT/BPF_JUMP macros)

Use them while converting classic BPF to internal
and in BPF testsuite later.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When register_net_sysctl failed, we should free the
sysctl_table.
Signed-off-by: NWang Weidong <wangweidong1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This revert commit efb842c4("sctp: optimize the sctp_sysctl_net_register"),
Since it doesn't kmemdup a sysctl_table for init_net, so the
init_net->sctp.sysctl_header->ctl_table_arg points to sctp_net_table
which is a static array pointer. So when doing sctp_sysctl_net_unregister,
it will free sctp_net_table, then we will get a NULL pointer dereference
like that:

[  262.948220] BUG: unable to handle kernel NULL pointer dereference at 000000000000006c
[  262.948232] IP: [<ffffffff81144b70>] kfree+0x80/0x420
[  262.948260] PGD db80a067 PUD dae12067 PMD 0
[  262.948268] Oops: 0000 [#1] SMP
[  262.948273] Modules linked in: sctp(-) crc32c_generic libcrc32c
...
[  262.948338] task: ffff8800db830190 ti: ffff8800dad00000 task.ti: ffff8800dad00000
[  262.948344] RIP: 0010:[<ffffffff81144b70>]  [<ffffffff81144b70>] kfree+0x80/0x420
[  262.948353] RSP: 0018:ffff8800dad01d88  EFLAGS: 00010046
[  262.948358] RAX: 0100000000000000 RBX: ffffffffa0227940 RCX: ffffea0000707888
[  262.948363] RDX: ffffea0000707888 RSI: 0000000000000001 RDI: ffffffffa0227940
[  262.948369] RBP: ffff8800dad01de8 R08: 0000000000000000 R09: ffff8800d9e983a9
[  262.948374] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0227940
[  262.948380] R13: ffffffff8187cfc0 R14: 0000000000000000 R15: ffffffff8187da10
[  262.948386] FS:  00007fa2a2658700(0000) GS:ffff880112800000(0000) knlGS:0000000000000000
[  262.948394] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  262.948400] CR2: 000000000000006c CR3: 00000000cddc0000 CR4: 00000000000006e0
[  262.948410] Stack:
[  262.948413]  ffff8800dad01da8 0000000000000286 0000000020227940 ffffffffa0227940
[  262.948422]  ffff8800dad01dd8 ffffffff811b7fa1 ffffffffa0227940 ffffffffa0227940
[  262.948431]  ffffffff8187d960 ffffffff8187cfc0 ffffffff8187d960 ffffffff8187da10
[  262.948440] Call Trace:
[  262.948457]  [<ffffffff811b7fa1>] ? unregister_sysctl_table+0x51/0xa0
[  262.948476]  [<ffffffffa020d1a1>] sctp_sysctl_net_unregister+0x21/0x30 [sctp]
[  262.948490]  [<ffffffffa020ef6d>] sctp_net_exit+0x12d/0x150 [sctp]
[  262.948512]  [<ffffffff81394f49>] ops_exit_list+0x39/0x60
[  262.948522]  [<ffffffff813951ed>] unregister_pernet_operations+0x3d/0x70
[  262.948530]  [<ffffffff81395292>] unregister_pernet_subsys+0x22/0x40
[  262.948544]  [<ffffffffa020efcc>] sctp_exit+0x3c/0x12d [sctp]
[  262.948562]  [<ffffffff810c5e04>] SyS_delete_module+0x194/0x210
[  262.948577]  [<ffffffff81240fde>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[  262.948587]  [<ffffffff815217a2>] system_call_fastpath+0x16/0x1b

With this revert, it won't occur the Oops.
Signed-off-by: NWang Weidong <wangweidong1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

unregister_net_sysctl_table will check the ctl_table_header,
so remove the unneed checking
Signed-off-by: NWang Weidong <wangweidong1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Each node action flag should be set or cleared separately, instead
we now set the whole flags variable in one shot, and it's turned
out to be hard to see which other flags are affected. Therefore,
for instance, we explicitly clear TIPC_WAIT_OWN_LINKS_DOWN bit in
node_lost_contact().
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Reviewed-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename node flags to action_flags as well as its enum names so
that they can reflect its real meanings.
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Reviewed-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Validating the UDP checksum is now done in UDP before handing
packets to the encapsulation layer. Note that this also eliminates
the "feature" where L2TP can ignore a non-zero UDP checksum (doing
this was contrary to RFC 1122).
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Moving validation of UDP checksum to be done in UDP not encap layer.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use skb_checksum_validate to verify checksum.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use skb_checksum_simple_validate to verify checksum.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use skb_checksum_simple_validate to verify checksum.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use skb_checksum_simple_validate to verify checksum.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use skb_checksum_simple_validate to verify checksum.
Signed-off-by: NTom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All the callers hold RTNL lock, so there is no need to use inet_addr_hash_lock
to protect the hash list.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Similarly, when CONFIG_SYSCTL is not set, ping_group_range should still
work, just that no one can change it. Therefore we should move it out of
sysctl_net_ipv4.c. And, it should not share the same seqlock with
ip_local_port_range.

BTW, rename it to ->ping_group_range instead.

Cc: David S. Miller <davem@davemloft.net>
Cc: Francois Romieu <romieu@fr.zoreil.com>
Reported-by: NStefan de Konink <stefan@konink.de>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When CONFIG_SYSCTL is not set, ip_local_port_range should still work,
just that no one can change it. Therefore we should move it out of sysctl_inet.c.
Also, rename it to ->ip_local_ports instead.

Cc: David S. Miller <davem@davemloft.net>
Cc: Francois Romieu <romieu@fr.zoreil.com>
Reported-by: NStefan de Konink <stefan@konink.de>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dst is released one line before we access it again with dst->error.

Fixes: 58e35d14 netfilter: ipv6: propagate routing errors from
ip6_route_me_harder()
Signed-off-by: NSergey Popovich <popovich_sergei@mail.ru>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Increment fib_info_cnt in fib_create_info() right after successfuly
alllocating fib_info structure, overwise fib_metrics allocation failure
leads to fib_info_cnt incorrectly decremented in free_fib_info(), called
on error path from fib_create_info().
Signed-off-by: NSergey Popovich <popovich_sergei@mail.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 8f0ea0fe (snmp: reduce percpu needs by 50%)
reduced snmp array size to 1, so technically it doesn't have to be
an array any more. What's more, after the following commit:

	commit 933393f5
	Date:   Thu Dec 22 11:58:51 2011 -0600

	    percpu: Remove irqsafe_cpu_xxx variants

	    We simply say that regular this_cpu use must be safe regardless of
	    preemption and interrupt state.  That has no material change for x86
	    and s390 implementations of this_cpu operations.  However, arches that
	    do not provide their own implementation for this_cpu operations will
	    now get code generated that disables interrupts instead of preemption.

probably no arch wants to have SNMP_ARRAY_SZ == 2. At least after
almost 3 years, no one complains.

So, just convert the array to a single pointer and remove snmp_mib_init()
and snmp_mib_free() as well.

Cc: Christoph Lameter <cl@linux.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>