When the server is unavailable due to a networking error, etc, we want
the RPC client to respect the timeout delays when attempting to reconnect.
Reported-by: NNeil Brown <neilb@suse.de>
Fixes: 561ec160 (SUNRPC: call_connect_status should recheck bind..)
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Since TCP is a stream protocol, our callback read code needs to take into
account the fact that RPC callbacks are not always confined to a single
TCP segment.
This patch adds support for multiple TCP segments by ensuring that we
only remove the rpc_rqst structure from the 'free backchannel requests'
list once the data has been completely received. We rely on the fact
that TCP data is ordered for the duration of the connection.
Reported-by: Nshaobingqing <shaobingqing@bwstor.com.cn>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The call to xprt_free_allocation() will call list_del() on
req->rq_bc_pa_list, which is not attached to a list.
This patch moves the list_del() out of xprt_free_allocation()
and into those callers that need it.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When a send failure occurs due to the socket being out of buffer space,
we call xs_nospace() in order to have the RPC task wait until the
socket has drained enough to make it worth while trying again.
The current patch fixes a race in which the socket is drained before
we get round to setting up the machinery in xs_nospace(), and which
is reported to cause hangs.

Link: http://lkml.kernel.org/r/20140210170315.33dfc621@notabene.brown
Fixes: a9a6b52e (SUNRPC: Don't start the retransmission timer...)
Reported-by: NNeil Brown <neilb@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

An infinite loop is caused when nfs4_establish_lease() fails
with -EACCES. This causes nfs4_handle_reclaim_lease_error()
to sleep a bit and resets the NFS4CLNT_LEASE_EXPIRED bit.
This in turn causes nfs4_state_manager() to try and
reestablished the lease, again, again, again...

The problem is a valid RPCSEC_GSS client is being created when
rpc.gssd is not running.

Link: http://lkml.kernel.org/r/1392066375-16502-1-git-send-email-steved@redhat.com
Fixes: 0ea9de0e (sunrpc: turn warn_gssd() log message into a dprintk())
Reported-by: NSteve Dickson <steved@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Commit f38a5181 ("ceph: Convert to immutable biovecs") introduced
a NULL pointer dereference, which broke rbd in -rc1.  Fix it.

Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Handling redirect replies requires both map_sem and request_mutex.
Taking map_sem unconditionally near the top of handle_reply() avoids
possible race conditions that arise from releasing request_mutex to be
able to acquire map_sem in redirect reply case.  (Lock ordering is:
map_sem, request_mutex, crush_mutex.)
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Factor out logic from ceph_osdc_start_request() into a new helper,
__ceph_osdc_start_request().  ceph_osdc_start_request() now amounts to
taking locks and calling __ceph_osdc_start_request().
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

msgpool_op_reply message pool isn't destroyed if workqueue construction
fails.  Fix it.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

The x32 case for the recvmsg() timout handling is broken:

  asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg,
                                      unsigned int vlen, unsigned int flags,
                                      struct compat_timespec __user *timeout)
  {
          int datagrams;
          struct timespec ktspec;

          if (flags & MSG_CMSG_COMPAT)
                  return -EINVAL;

          if (COMPAT_USE_64BIT_TIME)
                  return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
                                        flags | MSG_CMSG_COMPAT,
                                        (struct timespec *) timeout);
          ...

The timeout pointer parameter is provided by userland (hence the __user
annotation) but for x32 syscalls it's simply cast to a kernel pointer
and is passed to __sys_recvmmsg which will eventually directly
dereference it for both reading and writing.  Other callers to
__sys_recvmmsg properly copy from userland to the kernel first.

The bug was introduced by commit ee4fa23c ("compat: Use
COMPAT_USE_64BIT_TIME in net/compat.c") and should affect all kernels
since 3.4 (and perhaps vendor kernels if they backported x32 support
along with this code).

Note that CONFIG_X86_X32_ABI gets enabled at build time and only if
CONFIG_X86_X32 is enabled and ld can build x32 executables.

Other uses of COMPAT_USE_64BIT_TIME seem fine.

This addresses CVE-2014-0038.
Signed-off-by: NPaX Team <pageexec@freemail.hu>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> # v3.4+
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch fixed following Warning while executing "make htmldocs".

Warning(/net/core/skbuff.c:2164): No description found for parameter 'from'
Warning(/net/core/skbuff.c:2164): Excess function parameter 'source'
description in 'skb_zerocopy'
Replace "@source" with "@from" fixed the warning.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sending malformed llc packets triggers this spew, which seems excessive.

WARNING: CPU: 1 PID: 6917 at net/llc/llc_output.c:46 llc_mac_hdr_init+0x85/0x90 [llc]()
device type not supported: 0
CPU: 1 PID: 6917 Comm: trinity-c1 Not tainted 3.13.0+ #95
 0000000000000009 00000000007e257d ffff88009232fbe8 ffffffffac737325
 ffff88009232fc30 ffff88009232fc20 ffffffffac06d28d ffff88020e07f180
 ffff88009232fec0 00000000000000c8 0000000000000000 ffff88009232fe70
Call Trace:
 [<ffffffffac737325>] dump_stack+0x4e/0x7a
 [<ffffffffac06d28d>] warn_slowpath_common+0x7d/0xa0
 [<ffffffffac06d30c>] warn_slowpath_fmt+0x5c/0x80
 [<ffffffffc01736d5>] llc_mac_hdr_init+0x85/0x90 [llc]
 [<ffffffffc0173759>] llc_build_and_send_ui_pkt+0x79/0x90 [llc]
 [<ffffffffc057cdba>] llc_ui_sendmsg+0x23a/0x400 [llc2]
 [<ffffffffac605d8c>] sock_sendmsg+0x9c/0xe0
 [<ffffffffac185a37>] ? might_fault+0x47/0x50
 [<ffffffffac606321>] SYSC_sendto+0x121/0x1c0
 [<ffffffffac011847>] ? syscall_trace_enter+0x207/0x270
 [<ffffffffac6071ce>] SyS_sendto+0xe/0x10
 [<ffffffffac74aaa4>] tracesys+0xdd/0xe2

Until 2009, this was a printk, when it was changed in
bf9ae538: "llc: use dev_hard_header".

Let userland figure out what -EINVAL means by itself.
Signed-off-by: NDave Jones <davej@fedoraproject.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When dealing with icmp messages, the skb->data points the
ip header that triggered the sending of the icmp message.

In gre_cisco_err(), the parse_gre_header() is called, and the
iptunnel_pull_header() is called to pull the skb at the end of
the parse_gre_header(), so the skb->data doesn't point the
inner ip header.

Unfortunately, the ipgre_err still needs those ip addresses in
inner ip header to look up tunnel by ip_tunnel_lookup().

So just use icmp_hdr() to get inner ip header instead of skb->data.
Signed-off-by: NDuan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I see a memory leak when using a transparent HTTP proxy using TPROXY
together with TCP early demux and Kernel v3.8.13.15 (Ubuntu stable):

unreferenced object 0xffff88008cba4a40 (size 1696):
  comm "softirq", pid 0, jiffies 4294944115 (age 8907.520s)
  hex dump (first 32 bytes):
    0a e0 20 6a 40 04 1b 37 92 be 32 e2 e8 b4 00 00  .. j@..7..2.....
    02 00 07 01 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff810b710a>] kmem_cache_alloc+0xad/0xb9
    [<ffffffff81270185>] sk_prot_alloc+0x29/0xc5
    [<ffffffff812702cf>] sk_clone_lock+0x14/0x283
    [<ffffffff812aaf3a>] inet_csk_clone_lock+0xf/0x7b
    [<ffffffff8129a893>] netlink_broadcast+0x14/0x16
    [<ffffffff812c1573>] tcp_create_openreq_child+0x1b/0x4c3
    [<ffffffff812c033e>] tcp_v4_syn_recv_sock+0x38/0x25d
    [<ffffffff812c13e4>] tcp_check_req+0x25c/0x3d0
    [<ffffffff812bf87a>] tcp_v4_do_rcv+0x287/0x40e
    [<ffffffff812a08a7>] ip_route_input_noref+0x843/0xa55
    [<ffffffff812bfeca>] tcp_v4_rcv+0x4c9/0x725
    [<ffffffff812a26f4>] ip_local_deliver_finish+0xe9/0x154
    [<ffffffff8127a927>] __netif_receive_skb+0x4b2/0x514
    [<ffffffff8127aa77>] process_backlog+0xee/0x1c5
    [<ffffffff8127c949>] net_rx_action+0xa7/0x200
    [<ffffffff81209d86>] add_interrupt_randomness+0x39/0x157

But there are many more, resulting in the machine going OOM after some
days.

From looking at the TPROXY code, and with help from Florian, I see
that the memory leak is introduced in tcp_v4_early_demux():

  void tcp_v4_early_demux(struct sk_buff *skb)
  {
    /* ... */

    iph = ip_hdr(skb);
    th = tcp_hdr(skb);

    if (th->doff < sizeof(struct tcphdr) / 4)
        return;

    sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
                       iph->saddr, th->source,
                       iph->daddr, ntohs(th->dest),
                       skb->skb_iif);
    if (sk) {
        skb->sk = sk;

where the socket is assigned unconditionally to skb->sk, also bumping
the refcnt on it.  This is problematic, because in our case the skb
has already a socket assigned in the TPROXY target.  This then results
in the leak I see.

The very same issue seems to be with IPv6, but haven't tested.
Reviewed-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NHolger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Follow redirect replies from osds, for details see ceph.git commit
fbbe3ad1220799b7bb00ea30fce581c5eadaf034.

v1 (current) version of redirect reply consists of oloc and oid, which
expands to pool, key, nspace, hash and oid.  However, server-side code
that would populate anything other than pool doesn't exist yet, and
hence this commit adds support for pool redirects only.  To make sure
that future server-side updates don't break us, we decode all fields
and, if any of key, nspace, hash or oid have a non-default value, error
out with "corrupt osd_op_reply ..." message.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Rename ceph_osd_request::r_{oloc,oid} to r_base_{oloc,oid} before
introducing r_target_{oloc,oid} needed for redirects.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Overwrite ceph_osd_request::r_oloc.pool with read_tier for read ops and
write_tier for write and read+write ops (aka basic tiering support).
{read,write}_tier are part of pg_pool_t since v9.  This commit bumps
our pg_pool_t decode compat version from v7 to v9, all new fields
except for {read,write}_tier are ignored.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

"Lookup pool info by ID" function is hidden in osdmap.c.  Expose it to
the rest of libceph.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Switch ceph_calc_ceph_pg() to new oloc and oid abstractions and rename
it to ceph_oloc_oid_to_pg() to make its purpose more clear.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

In preparation for tiering support, which would require having two
(base and target) object names for each osd request and also copying
those names around, introduce struct ceph_object_id (oid) and a couple
helpers to facilitate those copies and encapsulate the fact that object
name is not necessarily a NUL-terminated string.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

In preparation for adding oid abstraction, rename MAX_OBJ_NAME_SIZE to
CEPH_MAX_OID_NAME_LEN.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

Instead of relying on pool fields in ceph_file_layout (for mapping) and
ceph_pg (for enconding), start using ceph_object_locator (oloc)
abstraction.  Note that userspace oloc currently consists of pool, key,
nspace and hash fields, while this one contains only a pool.  This is
OK, because at this point we only send (i.e. encode) olocs and never
have to receive (i.e. decode) them.

This makes keeping a copy of ceph_file_layout in every osd request
unnecessary, so ceph_osd_request::r_file_layout field is nuked.
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

PTR_RET is deprecated. Use PTR_ERR_OR_ZERO instead. While at it
also include missing err.h header.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The original printk() made sense when the GSSAPI codepaths were called
only when sec=krb5* was explicitly requested. Now however, in many cases
the nfs client will try to acquire GSSAPI credentials by default, even
when it's not requested.

Since we don't have a great mechanism to distinguish between the two
cases, just turn the pr_warn into a dprintk instead. With this change we
can also get rid of the ratelimiting.

We do need to keep the EXPORT_SYMBOL(gssd_running) in place since
auth_gss.ko needs it and sunrpc.ko provides it. We can however,
eliminate the gssd_running call in the nfs code since that's a bit of a
layering violation.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This moves part of Eric Dumazets skb_gso_seglen helper from tbf sched to
skbuff core so it may be reused by upcoming ip forwarding path patch.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On input, CHECKSUM_PARTIAL should be treated the same way as
CHECKSUM_UNNECESSARY. See include/linux/skbuff.h
Signed-off-by: NTim Smith <tim@electronghost.co.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

skb_kill_datagram() does not dequeue the skb when MSG_PEEK is unset.
This leaves a free'd skb on the queue, resulting a double-free later.

Without this, the following oops can occur:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [<ffffffff8154fcf7>] skb_dequeue+0x47/0x70
PGD 0
Oops: 0002 [#1] SMP
Modules linked in: af_rxrpc ...
CPU: 0 PID: 1191 Comm: listen Not tainted 3.12.0+ #4
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
task: ffff8801183536b0 ti: ffff880035c92000 task.ti: ffff880035c92000
RIP: 0010:[<ffffffff8154fcf7>] skb_dequeue+0x47/0x70
RSP: 0018:ffff880035c93db8  EFLAGS: 00010097
RAX: 0000000000000246 RBX: ffff8800d2754b00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000202 RDI: ffff8800d254c084
RBP: ffff880035c93dd0 R08: ffff880035c93cf0 R09: ffff8800d968f270
R10: 0000000000000000 R11: 0000000000000293 R12: ffff8800d254c070
R13: ffff8800d254c084 R14: ffff8800cd861240 R15: ffff880119b39720
FS:  00007f37a969d740(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000008 CR3: 00000000d4413000 CR4: 00000000000006f0
Stack:
 ffff8800d254c000 ffff8800d254c070 ffff8800d254c2c0 ffff880035c93df8
 ffffffffa041a5b8 ffff8800cd844c80 ffffffffa04385a0 ffff8800cd844cb0
 ffff880035c93e18 ffffffff81546cef ffff8800d45fea00 0000000000000008
Call Trace:
 [<ffffffffa041a5b8>] rxrpc_release+0x128/0x2e0 [af_rxrpc]
 [<ffffffff81546cef>] sock_release+0x1f/0x80
 [<ffffffff81546d62>] sock_close+0x12/0x20
 [<ffffffff811aaba1>] __fput+0xe1/0x230
 [<ffffffff811aad3e>] ____fput+0xe/0x10
 [<ffffffff810862cc>] task_work_run+0xbc/0xe0
 [<ffffffff8106a3be>] do_exit+0x2be/0xa10
 [<ffffffff8116dc47>] ? do_munmap+0x297/0x3b0
 [<ffffffff8106ab8f>] do_group_exit+0x3f/0xa0
 [<ffffffff8106ac04>] SyS_exit_group+0x14/0x20
 [<ffffffff8166b069>] system_call_fastpath+0x16/0x1b
Signed-off-by: NTim Smith <tim@electronghost.co.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

If rx->conn is not NULL, rxrpc_connect_exclusive() does not
acquire the transport's client lock, but it still releases it.

The patch adds locking of the spinlock to this path.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a missing newline to a dout() in __reset_osd().
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>

Encapsulate kmalloc vs vmalloc memory allocation and freeing logic into
two helpers, ceph_kvmalloc() and ceph_kvfree(), and switch to them.

ceph_kvmalloc() kmalloc()'s a maximum of 8 pages, anything bigger is
vmalloc()'ed with __GFP_HIGHMEM set.  This changes the existing
behaviour:

- for buffers (ceph_buffer_new()), from trying to kmalloc() everything
  and using vmalloc() just as a fallback

- for messages (ceph_msg_new()), from going to vmalloc() for anything
  bigger than a page

- for messages (ceph_msg_new()), from disallowing vmalloc() to use high
  memory
Signed-off-by: NIlya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: NSage Weil <sage@inktank.com>

commit 25fb6ca4
"net IPv6 : Fix broken IPv6 routing table after loopback down-up"
allocates addrconf router for ipv6 address when lo device up.
but commit a881ae1f
"ipv6:don't call addrconf_dst_alloc again when enable lo" breaks
this behavior.

Since the addrconf router is moved to the garbage list when
lo device down, we should release this router and rellocate
a new one for ipv6 address when lo device up.

This patch solves bug 67951 on bugzilla
https://bugzilla.kernel.org/show_bug.cgi?id=67951

change from v1:
use ip6_rt_put to repleace ip6_del_rt, thanks Hannes!
change code style, suggested by Sergei.

CC: Sabrina Dubroca <sd@queasysnail.net>
CC: Hannes Frederic Sowa <hannes@stressinduktion.org>
Reported-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The two commits 0115e8e3 (net: remove delay at device dismantle) and
748e2d93 (net: reinstate rtnl in call_netdevice_notifiers()) silently
removed a NULL pointer check for in_dev since Linux 3.7.

This patch re-introduces this check as it causes crashing the kernel when
setting small mtu values on non-ip capable netdevices.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace hardcoded lowest common multiple algorithm by the lcm()
function in kernel lib.
Signed-off-by: NLuis Henriques <luis.henriques@canonical.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree
Signed-off-by: NCody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that the definition is centralized in <linux/kernel.h>, the
definitions of U32_MAX (and related) elsewhere in the kernel can be
removed.
Signed-off-by: NAlex Elder <elder@linaro.org>
Acked-by: NSage Weil <sage@inktank.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The symbol U32_MAX is defined in several spots.  Change these
definitions to be conditional.  This is in preparation for the next
patch, which centralizes the definition in <linux/kernel.h>.
Signed-off-by: NAlex Elder <elder@linaro.org>
Cc: Sage Weil <sage@inktank.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This check is not needed because the same check is done before
fill_slave_info is used in rtnl_link_slave_info_fill.
Also, by removing this check, kernel will fillup IFLA_INFO_SLAVE_KIND
even for slaves of masters which does not implement fill_slave_info.
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit a6222602("ip_tunnel: fix kernel panic with icmp_dest_unreach")
clear IPCB in ip_tunnel_xmit()  , or else skb->cb[] may contain garbage from
GSO segmentation layer.

But commit 0e6fbc5b("ip_tunnels: extend iptunnel_xmit()") refactor codes,
and it clear IPCB behind the dst_link_failure().

So clear IPCB in ip_tunnel_xmit() just like commti a6222602("ip_tunnel:
fix kernel panic with icmp_dest_unreach").
Signed-off-by: NDuan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we have multiple devices attempting to sync the same address
to a single destination, each device should be permitted to sync
it once.  To accomplish this, pass the 'sync_cnt' of the source
address when adding the addresss to the lower device.  'sync_cnt'
tracks how many time a given address has been succefully synced.
This way, we know that if the 'sync_cnt' passed in is 0, we should
sync this address.

Also, turn 'synced' member back into the counter as was originally
done in
   commit 4543fbef.
   net: count hw_addr syncs so that unsync works properly.
It tracks how many time a given address has been added via a
'sync' operation.  For every successfull 'sync' the counter is
incremented, and for ever 'unsync', the counter is decremented.
This makes sure that the address will be properly removed from
the the lower device when all the upper devices have removed it.
Reported-by: NAndrey Dmitrov <andrey.dmitrov@oktetlabs.ru>
CC: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru>
CC: Alexandra N. Kossovsky <Alexandra.Kossovsky@oktetlabs.ru>
CC: Konstantin Ushakov <Konstantin.Ushakov@oktetlabs.ru>
Signed-off-by: NVlad Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>