tcp_timeout_skb() was intended to trigger fast recovery on timeout,
unfortunately in reality it often causes spurious retransmission
storms during fast recovery. The particular sign is a fast retransmit
over the highest sacked sequence (SND.FACK).

Currently the RTO timer re-arming (as in RFC6298) offers a nice cushion
to avoid spurious timeout: when SND.UNA advances the sender re-arms
RTO and extends the timeout by icsk_rto. The sender does not offset
the time elapsed since the packet at SND.UNA was sent.

But if the next (DUP)ACK arrives later than ~RTTVAR and triggers
tcp_fastretrans_alert(), then tcp_timeout_skb() will mark any packet
sent before the icsk_rto interval lost, including one that's above the
highest sacked sequence. Most likely a large part of scorebard will be
marked.

If most packets are not lost then the subsequent DUPACKs with new SACK
blocks will cause the sender to continue to retransmit packets beyond
SND.FACK spuriously. Even if only one packet is lost the sender may
falsely retransmit almost the entire window.

The situation becomes common in the world of bufferbloat: the RTT
continues to grow as the queue builds up but RTTVAR remains small and
close to the minimum 200ms. If a data packet is lost and the DUPACK
triggered by the next data packet is slightly delayed, then a spurious
retransmission storm forms.

As the original comment on tcp_timeout_skb() suggests: the usefulness
of this feature is questionable. It also wastes cycles walking the
sack scoreboard and is actually harmful because of false recovery.

It's time to remove this.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NNandita Dukkipati <nanditad@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds the support of peer address for IPv6. For example, it is
possible to specify the remote end of a 6inY tunnel.
This was already possible in IPv4:
 ip addr add ip1 peer ip2 dev dev1

The peer address is specified with IFA_ADDRESS and the local address with
IFA_LOCAL (like explained in include/uapi/linux/if_addr.h).
Note that the API is not changed, because before this patch, it was not
possible to specify two different addresses in IFA_LOCAL and IFA_REMOTE.
There is a small change for the dump: if the peer is different from ::,
IFA_ADDRESS will contain the peer address instead of the local address.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This was added by commit 59b9997b (Revert "net: maintain namespace
isolation between vlan and real device").
In fact, before the initial commit - the one that is reverted -, this
statement was not present.
'skb->dev = dev' is already done in eth_type_trans(), which is call just
after.
Spotted-by: NAlain Ritoux <alain.ritoux@6wind.com>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_fixup_rcvbuf() contains a loop to estimate initial socket
rcv space needed for a given mss. With large MTU (like 64K on lo),
we can loop ~500 times and consume a lot of cpu cycles.

perf top of 200 concurrent netperf -t TCP_CRR

5.62%  netperf  [kernel.kallsyms]  [k] tcp_init_buffer_space
1.71%  netperf  [kernel.kallsyms]  [k] _raw_spin_lock
1.55%  netperf  [kernel.kallsyms]  [k] kmem_cache_free
1.51%  netperf  [kernel.kallsyms]  [k] tcp_transmit_skb
1.50%  netperf  [kernel.kallsyms]  [k] tcp_ack

Lets use a 100% factor, and remove the loop.

100% is needed anyway for tcp_adv_win_scale=1
default value, and is also the maximum factor.

Refs: commit b49960a0
      ("tcp: change tcp_adv_win_scale and tcp_rmem[2]")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We forget to call dev_put() on error path in xfrm6_fill_dst(),
its caller doesn't handle this.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is a hole in struct ip6_tnl_parm2, so we have to
zero the struct on stack before copying it to user-space.

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

We have seen multiple NULL dereferences in __inet6_lookup_established()

After analysis, I found that inet6_sk() could be NULL while the
check for sk_family == AF_INET6 was true.

Bug was added in linux-2.6.29 when RCU lookups were introduced in UDP
and TCP stacks.

Once an IPv6 socket, using SLAB_DESTROY_BY_RCU is inserted in a hash
table, we no longer can clear pinet6 field.

This patch extends logic used in commit fcbdf09d
("net: fix nulls list corruptions in sk_prot_alloc")

TCP/UDP/UDPLite IPv6 protocols provide their own .clear_sk() method
to make sure we do not clear pinet6 field.

At socket clone phase, we do not really care, as cloning the parent (non
NULL) pinet6 is not adding a fatal race.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

EXPORT_SYMBOL and inline directives are contradictory to each other.
The patch fixes this inconsistency.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NDenis Efremov <yefremov.denis@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

nc_worker accesses the originator table during its periodic
work, but since the originator table is freed before
stopping the worker this leads to a global protection fault.

Fix this by killing the worker (in nc_free) before freeing
the originator table.

Moreover tidy up the entire clean up routine by running all
the subcomponents freeing procedures first and then killing
the TT and the originator tables at the end.
Signed-off-by: NAntonio Quartulli <ordex@autistici.org>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>

In the outgoing ARP request snooping routine in DAT, ARP
Request sent by local clients which are supposed to be
replied by other local clients can be silently dropped.

The destination host will reply by itself through the LAN
and therefore there is no need to involve DAT.
Reported-by: NCarlos Quijano <carlos@crqgestion.es>
Signed-off-by: NAntonio Quartulli <ordex@autistici.org>
Tested-by: NCarlos Quijano <carlos@crqgestion.es>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>

Reported-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>
Acked-by: NMartin Hundebøll <martin@hundeboll.net>
Signed-off-by: NAntonio Quartulli <ordex@autistici.org>

batadv_param_set_ra() strips the trailing '\n' from the supplied
string buffer without checking the length of the buffer first. This
patches avoids random memory access and associated potential
crashes.
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>
Signed-off-by: NAntonio Quartulli <ordex@autistici.org>

Rather than having logic to calculate inner protocol in every
tunnel gso handler move it to gso code. This simplifies code.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current code works, but sort of by accident: it obviously didn't
intend the error return to be interpreted as "true".
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The worry here is that fragm_sz could be zero since it comes from
skb->data.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The bearer_id here comes from skb->data and it can be a number from 0 to
7.  The problem is that the ->links[] array has only 2 elements so I
have added a range check.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The return value is reversed from mutex_trylock().
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The same story as with fib_trie patch - vfree() from RCU callbacks
is legitimate now.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that vfree() can be called from interrupt contexts, there's no
need to play games with schedule_work() to escape calling vfree()
from RCU callbacks.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes race between inet_frag_lru_move() and inet_frag_lru_add()
which was introduced in commit 3ef0eb0d
("net: frag, move LRU list maintenance outside of rwlock")

One cpu already added new fragment queue into hash but not into LRU.
Other cpu found it in hash and tries to move it to the end of LRU.
This leads to NULL pointer dereference inside of list_move_tail().

Another possible race condition is between inet_frag_lru_move() and
inet_frag_lru_del(): move can happens after deletion.

This patch initializes LRU list head before adding fragment into hash and
inet_frag_lru_move() doesn't touches it if it's empty.

I saw this kernel oops two times in a couple of days.

[119482.128853] BUG: unable to handle kernel NULL pointer dereference at           (null)
[119482.132693] IP: [<ffffffff812ede89>] __list_del_entry+0x29/0xd0
[119482.136456] PGD 2148f6067 PUD 215ab9067 PMD 0
[119482.140221] Oops: 0000 [#1] SMP
[119482.144008] Modules linked in: vfat msdos fat 8021q fuse nfsd auth_rpcgss nfs_acl nfs lockd sunrpc ppp_async ppp_generic bridge slhc stp llc w83627ehf hwmon_vid snd_hda_codec_hdmi snd_hda_codec_realtek kvm_amd k10temp kvm snd_hda_intel snd_hda_codec edac_core radeon snd_hwdep ath9k snd_pcm ath9k_common snd_page_alloc ath9k_hw snd_timer snd soundcore drm_kms_helper ath ttm r8169 mii
[119482.152692] CPU 3
[119482.152721] Pid: 20, comm: ksoftirqd/3 Not tainted 3.9.0-zurg-00001-g9f95269 #132 To Be Filled By O.E.M. To Be Filled By O.E.M./RS880D
[119482.161478] RIP: 0010:[<ffffffff812ede89>]  [<ffffffff812ede89>] __list_del_entry+0x29/0xd0
[119482.166004] RSP: 0018:ffff880216d5db58  EFLAGS: 00010207
[119482.170568] RAX: 0000000000000000 RBX: ffff88020882b9c0 RCX: dead000000200200
[119482.175189] RDX: 0000000000000000 RSI: 0000000000000880 RDI: ffff88020882ba00
[119482.179860] RBP: ffff880216d5db58 R08: ffffffff8155c7f0 R09: 0000000000000014
[119482.184570] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88020882ba00
[119482.189337] R13: ffffffff81c8d780 R14: ffff880204357f00 R15: 00000000000005a0
[119482.194140] FS:  00007f58124dc700(0000) GS:ffff88021fcc0000(0000) knlGS:0000000000000000
[119482.198928] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[119482.203711] CR2: 0000000000000000 CR3: 00000002155f0000 CR4: 00000000000007e0
[119482.208533] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[119482.213371] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[119482.218221] Process ksoftirqd/3 (pid: 20, threadinfo ffff880216d5c000, task ffff880216d3a9a0)
[119482.223113] Stack:
[119482.228004]  ffff880216d5dbd8 ffffffff8155dcda 0000000000000000 ffff000200000001
[119482.233038]  ffff8802153c1f00 ffff880000289440 ffff880200000014 ffff88007bc72000
[119482.238083]  00000000000079d5 ffff88007bc72f44 ffffffff00000002 ffff880204357f00
[119482.243090] Call Trace:
[119482.248009]  [<ffffffff8155dcda>] ip_defrag+0x8fa/0xd10
[119482.252921]  [<ffffffff815a8013>] ipv4_conntrack_defrag+0x83/0xe0
[119482.257803]  [<ffffffff8154485b>] nf_iterate+0x8b/0xa0
[119482.262658]  [<ffffffff8155c7f0>] ? inet_del_offload+0x40/0x40
[119482.267527]  [<ffffffff815448e4>] nf_hook_slow+0x74/0x130
[119482.272412]  [<ffffffff8155c7f0>] ? inet_del_offload+0x40/0x40
[119482.277302]  [<ffffffff8155d068>] ip_rcv+0x268/0x320
[119482.282147]  [<ffffffff81519992>] __netif_receive_skb_core+0x612/0x7e0
[119482.286998]  [<ffffffff81519b78>] __netif_receive_skb+0x18/0x60
[119482.291826]  [<ffffffff8151a650>] process_backlog+0xa0/0x160
[119482.296648]  [<ffffffff81519f29>] net_rx_action+0x139/0x220
[119482.301403]  [<ffffffff81053707>] __do_softirq+0xe7/0x220
[119482.306103]  [<ffffffff81053868>] run_ksoftirqd+0x28/0x40
[119482.310809]  [<ffffffff81074f5f>] smpboot_thread_fn+0xff/0x1a0
[119482.315515]  [<ffffffff81074e60>] ? lg_local_lock_cpu+0x40/0x40
[119482.320219]  [<ffffffff8106d870>] kthread+0xc0/0xd0
[119482.324858]  [<ffffffff8106d7b0>] ? insert_kthread_work+0x40/0x40
[119482.329460]  [<ffffffff816c32dc>] ret_from_fork+0x7c/0xb0
[119482.334057]  [<ffffffff8106d7b0>] ? insert_kthread_work+0x40/0x40
[119482.338661] Code: 00 00 55 48 8b 17 48 b9 00 01 10 00 00 00 ad de 48 8b 47 08 48 89 e5 48 39 ca 74 29 48 b9 00 02 20 00 00 00 ad de 48 39 c8 74 7a <4c> 8b 00 4c 39 c7 75 53 4c 8b 42 08 4c 39 c7 75 2b 48 89 42 08
[119482.343787] RIP  [<ffffffff812ede89>] __list_del_entry+0x29/0xd0
[119482.348675]  RSP <ffff880216d5db58>
[119482.353493] CR2: 0000000000000000

Oops happened on this path:
ip_defrag() -> ip_frag_queue() -> inet_frag_lru_move() -> list_move_tail() -> __list_del_entry()
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Eric Dumazet <edumazet@google.com>
Cc: David S. Miller <davem@davemloft.net>
Acked-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sunrpc/auth_gss/gss_rpc_xdr.c: In function ‘gssx_dec_option_array’:
net/sunrpc/auth_gss/gss_rpc_xdr.c:258: warning: ‘creds’ may be used uninitialized in this function

Return early if count is zero, to make it clearer to the compiler (and the
casual reviewer) that no more processing is done.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

TCP metric cache expires entries after one hour.

This probably make sense for TCP RTT/RTTVAR/CWND, but not
for TCP fastopen cookies.

Its better to try previous cookie. If it appears to be obsolete,
server will send us new cookie anyway.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Jakub reported that it is fairly easy to trigger the BUG() macro
from user space with TPACKET_V3's RX_RING by just giving a wrong
header status flag. We already had a similar situation in commit
7f5c3e3a (``af_packet: remove BUG statement in
tpacket_destruct_skb'') where this was the case in the TX_RING
side that could be triggered from user space. So really, don't use
BUG() or BUG_ON() unless there's really no way out, and i.e.
don't use it for consistency checking when there's user space
involved, no excuses, especially not if you're slapping the user
with WARN + dump_stack + BUG all at once. The two functions are
of concern:

  prb_retire_current_block() [when block status != TP_STATUS_KERNEL]
  prb_open_block() [when block_status != TP_STATUS_KERNEL]

Calls to prb_open_block() are guarded by ealier checks if block_status
is really TP_STATUS_KERNEL (racy!), but the first one BUG() is easily
triggable from user space. System behaves still stable after they are
removed. Also remove that yoda condition entirely, since it's already
guarded.
Reported-by: NJakub Zawadzki <darkjames-ws@darkjames.pl>
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch set correct skb->protocol so that inner packet can
lookup correct gso handler.
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For ipv6 traffic, GRE can generate packet with strange GSO
bits, e.g. ipv4 packet with SKB_GSO_TCPV6 flag set.  Therefore
following patch relaxes check in inet gso handler to allow
such packet for segmentation.
This patch also fixes wrong skb->protocol set that was done in
gre_gso_segment() handler.
Reported-by: NSteinar H. Gunderson <sesse@google.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A bridge should only send topology change notice if it is not
the root bridge. It is possible for message age timer to elect itself
as a new root bridge, and still have a topology change timer running
but waiting for bridge lock on other CPU.

Solve the race by checking if we are root bridge before continuing.
This was the root cause of the cases where br_send_tcn_bpdu would OOPS.
Reported-by: NJerryKang <jerry.kang@samsung.com>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When sending packets, TIPC bearers use skb_clone() before writing their
hardware header. This will however NOT copy the data buffer.
So when the same packet is sent over multiple bearers (to reach multiple
nodes), the same socket buffer data will be treated by multiple
tipc_media drivers which will write their own hardware header through
dev_hard_header().
Most of the time this is not a problem, because by the time the
packet is processed by the second media, it has already been sent over
the first one. However, when the first transmission is delayed (e.g.
because of insufficient bandwidth or through a shaper), the next bearer
will overwrite the hardware header, resulting in the packet being sent:
a) with the wrong source address, when bearers of the same type,
e.g. ethernet, are involved
b) with a completely corrupt header, or even dropped, when bearers of
different types are involved.

So when the same socket buffer is to be sent multiple times, send a
pskb_copy() instead (from the second instance on), and release it
afterwards (the bearer will skb_clone() it anyway).
Signed-off-by: NGerlando Falauto <gerlando.falauto@keymile.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NGerlando Falauto <gerlando.falauto@keymile.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NGerlando Falauto <gerlando.falauto@keymile.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Just convert those messages to dprintk()s so that they can be used
when debugging.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Create a slab cache to manage allocation of ceph_osdc_request
structures.

This resolves:
    http://tracker.ceph.com/issues/3926Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Create a slab cache to manage ceph_msg_data structure allocation.

This is part of:
    http://tracker.ceph.com/issues/3926Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Create a slab cache to manage ceph_msg structure allocation.

This is part of:
    http://tracker.ceph.com/issues/3926Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

This creates a new source file "net/ceph/snapshot.c" to contain
utility routines related to ceph snapshot contexts.  The main
motivation was to define ceph_create_snap_context() as a common way
to create these structures, but I've moved the definitions of
ceph_get_snap_context() and ceph_put_snap_context() there too.
(The benefit of inlining those is very small, and I'd rather
keep this collection of functions together.)
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

A WATCH op includes an object version.  The version that's supplied
is incorrectly byte-swapped osd_req_op_watch_init() where it's first
assigned (it's been this way since that code was first added).

The result is that the version sent to the osd is wrong, because
that value gets byte-swapped again in osd_req_encode_op().  This
is the source of a sparse warning related to improper byte order in
the assignment.

The approach of using the version to avoid a race is deprecated
(see http://tracker.ceph.com/issues/3871), and the watch parameter
is no longer even examined by the osd.  So fix the assignment in
osd_req_op_watch_init() so it no longer does the byte swap.

This resolves:
    http://tracker.ceph.com/issues/3847Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Add the ability to provide an array of pages as outbound request
data for object class method calls.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

This patch makes four small changes in the ceph messenger.

While getting copyup functionality working I found two bugs in the
messenger.  Existing paths through the code did not trigger these
problems, but they're fixed here:
    - In ceph_msg_data_pagelist_cursor_init(), the cursor's
      last_piece field was being checked against the length
      supplied.  This was OK until this commit: ccba6d98 libceph:
      implement multiple data items in a message That commit changed
      the cursor init routines to allow lengths to be supplied that
      exceeded the size of the current data item. Because of this,
      we have to use the assigned cursor resid field rather than the
      provided length in determining whether the cursor points to
      the last piece of a data item.
    - In ceph_msg_data_add_pages(), a BUG_ON() was erroneously
      catching attempts to add page data to a message if the message
      already had data assigned to it. That was OK until that same
      commit, at which point it was fine for messages to have
      multiple data items. It slipped through because that BUG_ON()
      call was present twice in that function. (You can never be too
      careful.)

In addition two other minor things are changed:
    - In ceph_msg_data_cursor_init(), the local variable "data" was
      getting assigned twice.
    - In ceph_msg_data_advance(), it was assumed that the
      type-specific advance routine would set new_piece to true
      after it advanced past the last piece. That may have been
      fine, but since we check for that case we might as well set it
      explicitly in ceph_msg_data_advance().

This resolves:
    http://tracker.ceph.com/issues/4762Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>

Allow osd request ops that aren't otherwise structured (not class,
extent, or watch ops) to specify "raw" data to be used to hold
incoming data for the op.  Make use of this capability for the osd
STAT op.

Prefix the name of the private function osd_req_op_init() with "_",
and expose a new function by that (earlier) name whose purpose is to
initialize osd ops with (only) implied data.

For now we'll just support the use of a page array for an osd op
with incoming raw data.
Signed-off-by: NAlex Elder <elder@inktank.com>
Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>