over time there were multiple requests to access different data
structures and fields of task_struct current, so finally add
the helper to access 'current' as-is. Tracing bpf programs will do
the rest of walking the pointers via bpf_probe_read().
Note that current can be null and bpf program has to deal it with,
but even dumb passing null into bpf_probe_read() is still safe.
Suggested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

The routing table of every switch in a tree is currently initialized to
all zeros. This is an issue since 0 is a valid port number.

Add a DSA_RTABLE_NONE=-1 constant to initialize the signed values of the
routing table pointing to other switches.

This fixes the device mapping of the mv88e6xxx driver where the port
pointing to the switch itself and to non-existent switches was wrongly
configured to be 0. It is now set to the expected 0xf value.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

The referenced change added a netlink notifier for processing
device queue size events.  These events are fired for all devices
but the registered callback assumed they only occurred for tun
devices.  This fix adds a check (borrowed from macvtap.c) to discard
non-tun device events.

For reference, this fixes the following splat:
[   71.505935] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
[   71.513870] IP: [<ffffffff8153c1a0>] tun_device_event+0x110/0x340
[   71.519906] PGD 3f41f56067 PUD 3f264b7067 PMD 0
[   71.524497] Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
[   71.529374] gsmi: Log Shutdown Reason 0x03
[   71.533417] Modules linked in:[   71.533826] mlx4_en: eth1: Link Up

[   71.539616]  bonding w1_therm wire cdc_acm ehci_pci ehci_hcd mlx4_en ib_uverbs mlx4_ib ib_core mlx4_core
[   71.549282] CPU: 12 PID: 7915 Comm: set.ixion-haswe Not tainted 4.7.0-dbx-DEV #8
[   71.556586] Hardware name: Intel Grantley,Wellsburg/Ixion_IT_15, BIOS 2.58.0 05/03/2016
[   71.564495] task: ffff887f00bb20c0 ti: ffff887f00798000 task.ti: ffff887f00798000
[   71.571894] RIP: 0010:[<ffffffff8153c1a0>]  [<ffffffff8153c1a0>] tun_device_event+0x110/0x340
[   71.580327] RSP: 0018:ffff887f0079bbd8  EFLAGS: 00010202
[   71.585576] RAX: fffffffffffffae8 RBX: ffff887ef6d03378 RCX: 0000000000000000
[   71.592624] RDX: 0000000000000000 RSI: 0000000000000028 RDI: 0000000000000000
[   71.599675] RBP: ffff887f0079bc48 R08: 0000000000000000 R09: 0000000000000001
[   71.606730] R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000010
[   71.613780] R13: 0000000000000000 R14: 0000000000000001 R15: ffff887f0079bd00
[   71.620832] FS:  00007f5cdc581700(0000) GS:ffff883f7f700000(0000) knlGS:0000000000000000
[   71.628826] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   71.634500] CR2: 0000000000000010 CR3: 0000003f3eb62000 CR4: 00000000001406e0
[   71.641549] Stack:
[   71.643533]  ffff887f0079bc08 0000000000000246 000000000000001e ffff887ef6d00000
[   71.650871]  ffff887f0079bd00 0000000000000000 0000000000000000 ffffffff00000000
[   71.658210]  ffff887f0079bc48 ffffffff81d24070 00000000fffffff9 ffffffff81cec7a0
[   71.665549] Call Trace:
[   71.667975]  [<ffffffff810eeb0d>] notifier_call_chain+0x5d/0x80
[   71.673823]  [<ffffffff816365d0>] ? show_tx_maxrate+0x30/0x30
[   71.679502]  [<ffffffff810eeb3e>] __raw_notifier_call_chain+0xe/0x10
[   71.685778]  [<ffffffff810eeb56>] raw_notifier_call_chain+0x16/0x20
[   71.691976]  [<ffffffff8160eb30>] call_netdevice_notifiers_info+0x40/0x70
[   71.698681]  [<ffffffff8160ec36>] call_netdevice_notifiers+0x16/0x20
[   71.704956]  [<ffffffff81636636>] change_tx_queue_len+0x66/0x90
[   71.710807]  [<ffffffff816381ef>] netdev_store.isra.5+0xbf/0xd0
[   71.716658]  [<ffffffff81638350>] tx_queue_len_store+0x50/0x60
[   71.722431]  [<ffffffff814a6798>] dev_attr_store+0x18/0x30
[   71.727857]  [<ffffffff812ea3ff>] sysfs_kf_write+0x4f/0x70
[   71.733274]  [<ffffffff812e9507>] kernfs_fop_write+0x147/0x1d0
[   71.739045]  [<ffffffff81134a4f>] ? rcu_read_lock_sched_held+0x8f/0xa0
[   71.745499]  [<ffffffff8125a108>] __vfs_write+0x28/0x120
[   71.750748]  [<ffffffff8111b137>] ? percpu_down_read+0x57/0x90
[   71.756516]  [<ffffffff8125d7d8>] ? __sb_start_write+0xc8/0xe0
[   71.762278]  [<ffffffff8125d7d8>] ? __sb_start_write+0xc8/0xe0
[   71.768038]  [<ffffffff8125bd5e>] vfs_write+0xbe/0x1b0
[   71.773113]  [<ffffffff8125c092>] SyS_write+0x52/0xa0
[   71.778110]  [<ffffffff817528e5>] entry_SYSCALL_64_fastpath+0x18/0xa8
[   71.784472] Code: 45 31 f6 48 8b 93 78 33 00 00 48 81 c3 78 33 00 00 48 39 d3 48 8d 82 e8 fa ff ff 74 25 48 8d b0 40 05 00 00 49 63 d6 41 83 c6 01 <49> 89 34 d4 48 8b 90 18 05 00 00 48 39 d3 48 8d 82 e8 fa ff ff
[   71.803655] RIP  [<ffffffff8153c1a0>] tun_device_event+0x110/0x340
[   71.809769]  RSP <ffff887f0079bbd8>
[   71.813213] CR2: 0000000000000010
[   71.816512] ---[ end trace 4db6449606319f73 ]---

Fixes: 1576d986 ("tun: switch to use skb array for tx")
Signed-off-by: Craig Gallek <kraig@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'rxrpc-rewrite-20160706' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

David Howells says:

====================
rxrpc: Improve conn/call lookup and fix call number generation [ver #3]

I've fixed a couple of patch descriptions and excised the patch that
duplicated the connections list for reconsideration at a later date.

For reference, the excised patch is sitting on the rxrpc-experimental
branch of my git tree, based on top of the rxrpc-rewrite branch.  Diffing
it against yesterday's tag shows no differences.

Would you prefer the patch set to be emailed afresh instead of a git-pull
request?

David
---
Here's the next part of the AF_RXRPC rewrite.  The two main purposes of
this set are to fix the call number handling and to make use of RCU when
looking up the connection or call to pass a received packet to.

Important changes in this set include:

 (1) Avoidance of placing stack data into SG lists in rxkad so that kernel
     stacks can become vmalloc'd (Herbert Xu).

 (2) Calls cease pinning the connection they used as soon as possible,
     which allows the connection to be discarded sooner and allows the call
     channel on that connection to be reused earlier.

 (3) Make each call channel on a connection have a separate and independent
     call number space rather than having a shared number space for the
     connection.  Call numbers should increment monotonically per channel
     on the client, and the server should ignore a call with a lower call
     number for that channel than the latest it has seen.  The RESPONSE
     packet sets the minimum values of each call ID counter on a
     connection.

 (4) Look up calls by indexing the channel array on a connection rather
     than by keeping calls in an rbtree on that connection.  Also look up
     calls using the channel array rather than using a hashtable.

     The call hashtable can then be removed.

 (5) Call terminal statuses are cached in the channel array for the last
     call.  It is assumed that if we the server have seen call N, then the
     client no longer cares about call N-1 on the same channel.

     This will allow retransmission of the terminal status in future
     without the need to keep the rxrpc_call struct around.

 (6) Peer lookups are moved out of common connection handling code and into
     service connection handling code as client connections (a) must point
     to a peer before they can be used and (b) are looked up by a
     machine-unique connection ID directly, so we only need to look up the
     peer first if we're going to deal with a service call.

 (7) The reference count on a connection is held elevated by 1 whilst it is
     alive (ie. idle unused connections have a refcount of 1).  The reaper
     will attempt to change the refcount from 1->0 and skip if this cannot
     be done, whilst look ups only increment the refcount if it's non-zero.

     This makes the implementation of RCU lookups easier as we don't have
     to get a ref on the connection or a lock on the connection list to
     prevent a connection being reaped whilst we're contemplating queueing
     a packet that initiates a new service call upon it.

     If we need to get a connection, but there's a dead connection in the
     tree, we use rb_replace_node() to replace the dead one with a new one.

 (8) Use a seqlock to validate the walk over the service connection rbtree
     attached to a peer when it's being walked in RCU mode.

 (9) Make the incoming call/connection packet handling code use RCU mode
     and locks and make it only take a reference if the call/connection
     gets queued on a workqueue.

The intention is that the next set will introduce the connection lifetime
management and capacity limits to prevent clients from overloading the
server.

There are some fixes too:

 (1) Verifying that a packet coming in to a client connection came from the
     expected source.

 (2) Fix handling of connection failure in client call creation where we
     don't reinitialise the list linkage block and a second attempt to
     unlink the failed connection oopses and also we don't set the state
     correctly, which causes an assertion failure.

 (3) New service calls were being added to the socket's accept queue under
     the wrong lock.

Changes:

 (V2) In rxrpc_find_service_conn_rcu() initialised the sequence number to 0.

      Fixed the RCU handling in conn_service.c by introducing and using
      rb_replace_node_rcu() as an RCU-safe alternative in
      rxrpc_publish_service_conn().

      Modified and used rcu_dereference_raw() to avoid RCU sparse warnings
      in rxrpc_find_service_conn_rcu().

      Added in some missing RCU dereference wrappers.  It seems to be
      necessary to turn on CONFIG_PROVE_RCU_REPEATEDLY as well as
      CONFIG_SPARSE_RCU_POINTER to get the static __rcu annotation checking
      to happen.

      Fixed some other sparse warnings, including a missing ntohs() in
      jumbo packet processing.

 (V3) Fixed some commit descriptions.

      Excised the patch that duplicated the connection list to separate out
      the procfs list for reconsideration at a later date.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Use the new APIs for eliminating a copy on the receive path. These new APIs also
help in minimizing the number of memory barriers we end up issuing (in the
ringbuffer code) since we can better control when we want to expose the ring
state to the host.

The patch is being resent to address earlier email issues.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

hfsc_sched is huge (size: 920, cachelines: 15), but we can get it to 14
cachelines by placing level after filter_cnt (covering 4 byte hole) and
reducing period/nactive/flags to u32 (period is just a counter,
incremented when class becomes active -- 2**32 is plenty for this
purpose, also, long is only 32bit wide on 32bit platforms anyway).

cl_vtperiod is exported to userspace via tc_hfsc_stats, but its period
member is already u32, so no precision is lost there either.

Cc: Michal Soltys <soltys@ziu.info>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'mac80211-next-for-davem-2016-07-06' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next

Johannes Berg says:

====================
One more set of new features:
 * beacon report (for radio measurement) support in cfg80211/mac80211
 * hwsim: allow wmediumd in namespaces
 * mac80211: extend 160MHz workaround to CSA IEs
 * mesh: properly encrypt group-addressed privacy action frames
 * mesh: allow setting peer AID
 * first steps for MU-MIMO monitor mode
 * along with various other cleanups and improvements
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Remove .owner field since calls to module_platform_driver() will
set it automatically.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:
	drivers/net/ethernet/mellanox/mlx5/core/en.h
	drivers/net/ethernet/mellanox/mlx5/core/en_main.c
	drivers/net/usb/r8152.c

All three conflicts were overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:

 1) All users of AF_PACKET's fanout feature want a symmetric packet
    header hash for load balancing purposes, so give it to them.

 2) Fix vlan state synchronization in e1000e, from Jarod Wilson.

 3) Use correct socket pointer in ip_skb_dst_mtu(), from Shmulik
    Ladkani.

 4) mlx5 bug fixes from Mohamad Haj Yahia, Daniel Jurgens, Matthew
    Finlay, Rana Shahout, and Shaker Daibes.  Mostly to do with
    operation timeouts and PCI error handling.

 5) Fix checksum handling in mirred packet action, from WANG Cong.

 6) Set skb->dev correctly when transmitting in !protect_frames case of
    macsec driver, from Daniel Borkmann.

 7) Fix MTU calculation in geneve driver, from Haishuang Yan.

 8) Missing netif_napi_del() in unregister path of qeth driver, from
    Ursula Braun.

 9) Handle malformed route netlink messages in decnet properly, from
    Vergard Nossum.

10) Memory leak of percpu data in ipv6 routing code, from Martin KaFai
    Lau.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (41 commits)
  ipv6: Fix mem leak in rt6i_pcpu
  net: fix decnet rtnexthop parsing
  cxgb4: update latest firmware version supported
  net/mlx5: Avoid setting unused var when modifying vport node GUID
  bonding: fix enslavement slave link notifications
  r8152: fix runtime function for RTL8152
  qeth: delete napi struct when removing a qeth device
  Revert "fsl/fman: fix error handling"
  fsl/fman: fix error handling
  cdc_ncm: workaround for EM7455 "silent" data interface
  RDS: fix rds_tcp_init() error path
  geneve: fix max_mtu setting
  net: phy: dp83867: Fix initialization of PHYCR register
  enc28j60: Fix race condition in enc28j60 driver
  net: stmmac: Fix null-function call in ISR on stmmac1000
  tipc: fix nl compat regression for link statistics
  net: bcmsysport: Device stats are unsigned long
  macsec: set actual real device for xmit when !protect_frames
  net_sched: fix mirrored packets checksum
  packet: Use symmetric hash for PACKET_FANOUT_HASH.
  ...

Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following patchset contains Netfilter updates for net-next,
they are:

1) Don't use userspace datatypes in bridge netfilter code, from
   Tobin Harding.

2) Iterate only once over the expectation table when removing the
   helper module, instead of once per-netns, from Florian Westphal.

3) Extra sanitization in xt_hook_ops_alloc() to return error in case
   we ever pass zero hooks, xt_hook_ops_alloc():

4) Handle NFPROTO_INET from the logging core infrastructure, from
   Liping Zhang.

5) Autoload loggers when TRACE target is used from rules, this doesn't
   change the behaviour in case the user already selected nfnetlink_log
   as preferred way to print tracing logs, also from Liping Zhang.

6) Conntrack slabs with SLAB_HWCACHE_ALIGN to allow rearranging fields
   by cache lines, increases the size of entries in 11% per entry.
   From Florian Westphal.

7) Skip zone comparison if CONFIG_NF_CONNTRACK_ZONES=n, from Florian.

8) Remove useless defensive check in nf_logger_find_get() from Shivani
   Bhardwaj.

9) Remove zone extension as place it in the conntrack object, this is
   always include in the hashing and we expect more intensive use of
   zones since containers are in place. Also from Florian Westphal.

10) Owner match now works from any namespace, from Eric Bierdeman.

11) Make sure we only reply with TCP reset to TCP traffic from
    nf_reject_ipv4, patch from Liping Zhang.

12) Introduce --nflog-size to indicate amount of network packet bytes
    that are copied to userspace via log message, from Vishwanath Pai.
    This obsoletes --nflog-range that has never worked, it was designed
    to achieve this but it has never worked.

13) Introduce generic macros for nf_tables object generation masks.

14) Use generation mask in table, chain and set objects in nf_tables.
    This allows fixes interferences with ongoing preparation phase of
    the commit protocol and object listings going on at the same time.
    This update is introduced in three patches, one per object.

15) Check if the object is active in the next generation for element
    deactivation in the rbtree implementation, given that deactivation
    happens from the commit phase path we have to observe the future
    status of the object.

16) Support for deletion of just added elements in the hash set type.

17) Allow to resize hashtable from /proc entry, not only from the
    obscure /sys entry that maps to the module parameter, from Florian
    Westphal.

18) Get rid of NFT_BASECHAIN_DISABLED, this code is not exercised
    anymore since we tear down the ruleset whenever the netdevice
    goes away.

19) Support for matching inverted set lookups, from Arturo Borrero.

20) Simplify the iptables_mangle_hook() by removing a superfluous
    extra branch.

21) Introduce ether_addr_equal_masked() and use it from the netfilter
    codebase, from Joe Perches.

22) Remove references to "Use netfilter MARK value as routing key"
    from the Netfilter Kconfig description given that this toggle
    doesn't exists already for 10 years, from Moritz Sichert.

23) Introduce generic NF_INVF() and use it from the xtables codebase,
    from Joe Perches.

24) Setting logger to NONE via /proc was not working unless explicit
    nul-termination was included in the string. This fixes seems to
    leave the former behaviour there, so we don't break backward.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull sound fixes from Takashi Iwai:
 "Here are a collection of small fixes: at this time, we've got a
  slightly high amount, but all small and trivial fixes, and nothing
  scary can be seen there"

* tag 'sound-4.7-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (21 commits)
  ALSA: hda/realtek: Add Lenovo L460 to docking unit fixup
  ALSA: timer: Fix negative queue usage by racy accesses
  ASoC: rt5645: fix reg-2f default value.
  ASoC: fsl_ssi: Fix number of words per frame for I2S-slave mode
  ALSA: au88x0: Fix calculation in vortex_wtdma_bufshift()
  ALSA: hda - Add PCI ID for Kabylake-H
  ALSA: echoaudio: Fix memory allocation
  ASoC: Intel: atom: fix missing breaks that would cause the wrong operation to execute
  ALSA: hda - fix read before array start
  ASoC: cx20442: set tty->receiver_room in v253_open
  ASoC: ak4613: Enable cache usage to fix crashes on resume
  ASoC: wm8940: Enable cache usage to fix crashes on resume
  ASoC: Intel: Skylake: Initialize module list for Broxton
  ASoC: wm5102: Correct supported channels on trace compressed DAI
  ASoC: wm5110: Add missing route from OUT3R to SYSCLK
  ASoC: rt5670: fix HP Playback Volume control
  ASoC: hdmi-codec: select CONFIG_HDMI
  ASoC: davinci-mcasp: Fix dra7 DMA offset when using CFG port
  ASoC: hdac_hdmi: Fix potential NULL dereference
  ASoC: ak4613: Remove owner assignment from platform_driver
  ...

Pull chrome platform fix from Olof Johansson:
 "A single fix this time, closing a window where ioctl args are fetched
  twice"

* tag 'chrome-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/olof/chrome-platform:
  platform/chrome: cros_ec_dev - double fetch bug in ioctl

Previously, mesh power management functionality works only with kernel
MPM. Because user space MPM did not report mesh peer AID to kernel,
the kernel could not identify the bit in TIM element. So this patch
adds mesh peer AID setting API.
Signed-off-by: Masashi Honma <masashi.honma@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Continuing the workaround implemented in commit 23665aaf
("mac80211: Interoperability workaround for 80+80 and 160 MHz channels")
use the same code to parse the Wide Bandwidth Channel Switch element
by converting to VHT Operation element since the spec also just refers
to that for parsing semantics, particularly with the workaround.

While at it, remove some dead code - the IEEE80211_STA_DISABLE_40MHZ
flag can never be set at this point since it's checked earlier and the
wide_bw_chansw_ie pointer is set to NULL if it's set.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Rather than reporting the scan as having completed, report it as
being aborted.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Add the following to support beacon report radio measurement
with the measurement mode field set to passive or active:
1. Propagate the required scan duration to the device
2. Report the scan start time (in terms of TSF)
3. Report each BSS's detection time (also in terms of TSF)

TSF times refer to the BSS that the interface that requested the
scan is connected to.
Signed-off-by: Assaf Krauss <assaf.krauss@intel.com>
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
[changed ath9k/10k, at76c59x-usb, iwlegacy, wl1251 and wlcore to match
the new API]
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Beacon report radio measurement requires reporting observed BSSs
on the channels specified in the beacon request. If the measurement
mode is set to passive or active, it requires actually performing a
scan (passive or active, accordingly), and reporting the time that
the scan was started and the time each beacon/probe was received
(both in terms of TSF of the BSS of the requesting AP). If the
request mode is table, this information is optional.
In addition, the radio measurement request specifies the channel
dwell time for the measurement.

In order to use scan for beacon report when the mode is active or
passive, add a parameter to scan request that specifies the
channel dwell time, and add scan start time and beacon received time
to scan results information.

Supporting beacon report is required for Multi Band Operation (MBO).
Signed-off-by: Assaf Krauss <assaf.krauss@intel.com>
Signed-off-by: David Spinadel <david.spinadel@intel.com>
Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The API expects a pointer to a signed int so we should not use an
unsigned int for it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Add radar_detect_widths to the interface combination that allows
concurrent P2P Device dedicated interface and AP interfaces, to enable
testing of radar detection when P2P Device interface is used.

Clear the radar_detect_widths in case of multi channel contexts
as this is not currently supported.

As radar_detect_widths are now supported in all combinations,
remove the hwsim_if_dfs_limits definition since it is no longer
needed.
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

add API to support VHT MU-MIMO air sniffer.
in MU-MIMO there are parallel frames on the air while the HW
has only one RX.
add the capability to sniff one of the MU-MIMO parallel frames by
giving the sniffer additional information so it'll know which
of the parallel frames it shall follow.

Add attribute - NL80211_ATTR_MU_MIMO_GROUP_DATA - for getting
a MU-MIMO groupID in order to monitor packets from that group
using VHT MU-MIMO.
And add attribute -NL80211_ATTR_MU_MIMO_FOLLOW_ADDR - for passing
MAC address to monitor mode.
that option will be used by VHT MU-MIMO air sniffer to follow a
station according to it's MAC address using VHT MU-MIMO.
Signed-off-by: Aviya Erenfeld <aviya.erenfeld@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The current implementation of handling ADDBA Request while a session
is already active with the peer is wrong - in case the peer is using
the existing session's dialog token this should be treated as update
to the session, which can update the timeout value.

We don't really have a good way of supporting that, so reject, but
implement the required behaviour in the spec of "Even if the updated
ADDBA Request frame is not accepted, the original Block ACK setup
remains active." (802.11-2012 10.5.4)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The call hash table is now no longer used as calls are looked up directly
by channel slot on the connection, so kill it off.
Signed-off-by: David Howells <dhowells@redhat.com>

Move to using RCU access to a peer's service connection tree when routing
an incoming packet.  This is done using a seqlock to trigger retrying of
the tree walk if a change happened.

Further, we no longer get a ref on the connection looked up in the
data_ready handler unless we queue the connection's work item - and then
only if the refcount > 0.


Note that I'm avoiding the use of a hash table for service connections
because each service connection is addressed by a 62-bit number
(constructed from epoch and connection ID >> 2) that would allow the client
to engage in bucket stuffing, given knowledge of the hash algorithm.
Peers, however, are hashed as the network address is less controllable by
the client.  The total number of peers will also be limited in a future
commit.
Signed-off-by: David Howells <dhowells@redhat.com>

Data structures that are used both with and without RCU protection
are difficult to write in a sparse-clean manner.  If you mark the
relevant pointers with __rcu, sparse will complain about all non-RCU
uses, but if you don't mark those pointers, sparse will complain about
all RCU uses.

This commit therefore suppresses sparse warnings for rcu_dereference_raw(),
allowing mixed-protection data structures to avoid these warnings.
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>

Implement an RCU-safe variant of rb_replace_node() and rearrange
rb_replace_node() to do things in the same order.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Move the peer lookup done in input.c by data_ready into
rxrpc_find_connection().
Signed-off-by: David Howells <dhowells@redhat.com>

Prune the contents of the rxrpc_conn_proto struct.  Most of the fields aren't
used anymore.
Signed-off-by: David Howells <dhowells@redhat.com>

Overhaul the usage count accounting for the rxrpc_connection struct to make
it easier to implement RCU access from the data_ready handler.

The problem is that currently we're using a lock to prevent the garbage
collector from trying to clean up a connection that we're contemplating
unidling.  We could just stick incoming packets on the connection we find,
but we've then got a problem that we may race when dispatching a work item
to process it as we need to give that a ref to prevent the rxrpc_connection
struct from disappearing in the meantime.

Further, incoming packets may get discarded if attached to an
rxrpc_connection struct that is going away.  Whilst this is not a total
disaster - the client will presumably resend - it would delay processing of
the call.  This would affect the AFS client filesystem's service manager
operation.

To this end:

 (1) We now maintain an extra count on the connection usage count whilst it
     is on the connection list.  This mean it is not in use when its
     refcount is 1.

 (2) When trying to reuse an old connection, we only increment the refcount
     if it is greater than 0.  If it is 0, we replace it in the tree with a
     new candidate connection.

 (3) Two connection flags are added to indicate whether or not a connection
     is in the local's client connection tree (used by sendmsg) or the
     peer's service connection tree (used by data_ready).  This makes sure
     that we don't try and remove a connection if it got replaced.

     The flags are tested under lock with the removal operation to prevent
     the reaper from killing the rxrpc_connection struct whilst someone
     else is trying to effect a replacement.

     This could probably be alleviated by using memory barriers between the
     flag set/test and the rb_tree ops.  The rb_tree op would still need to
     be under the lock, however.

 (4) When trying to reap an old connection, we try to flip the usage count
     from 1 to 0.  If it's not 1 at that point, then it must've come back
     to life temporarily and we ignore it.
Signed-off-by: David Howells <dhowells@redhat.com>

Move the lookup of a peer from a call that's being accepted into the
function that creates a new incoming connection.  This will allow us to
avoid incrementing the peer's usage count in some cases in future.

Note that I haven't bother to integrate rxrpc_get_addr_from_skb() with
rxrpc_extract_addr_from_skb() as I'm going to delete the former in the very
near future.
Signed-off-by: David Howells <dhowells@redhat.com>

Split the service-specific connection code out into into its own file.  The
client-specific code has already been split out.  This will leave just the
common code in the original file.
Signed-off-by: David Howells <dhowells@redhat.com>

Split the client-specific connection code out into its own file.  It will
behave somewhat differently from the service-specific connection code, so
it makes sense to separate them.
Signed-off-by: David Howells <dhowells@redhat.com>

Each channel on a connection has a separate, independent number space from
which to allocate callNumber values.  It is entirely possible, for example,
to have a connection with four active calls, each with call number 1.

Note that the callNumber values for any particular channel don't have to
start at 1, but they are supposed to increment monotonically for that
channel from a client's perspective and may not be reused once the call
number is transmitted (until the epoch cycles all the way back round).

Currently, however, call numbers are allocated on a per-connection basis
and, further, are held in an rb-tree.  The rb-tree is redundant as the four
channel pointers in the rxrpc_connection struct are entirely capable of
pointing to all the calls currently in progress on a connection.

To this end, make the following changes:

 (1) Handle call number allocation independently per channel.

 (2) Get rid of the conn->calls rb-tree.  This is overkill as a connection
     may have a maximum of four calls in progress at any one time.  Use the
     pointers in the channels[] array instead, indexed by the channel
     number from the packet.

 (3) For each channel, save the result of the last call that was in
     progress on that channel in conn->channels[] so that the final ACK or
     ABORT packet can be replayed if necessary.  Any call earlier than that
     is just ignored.  If we've seen the next call number in a packet, the
     last one is most definitely defunct.

 (4) When generating a RESPONSE packet for a connection, the call number
     counter for each channel must be included in it.

 (5) When parsing a RESPONSE packet for a connection, the call number
     counters contained therein should be used to set the minimum expected
     call numbers on each channel.

To do in future commits:

 (1) Replay terminal packets based on the last call stored in
     conn->channels[].

 (2) Connections should be retired before the callNumber space on any
     channel runs out.

 (3) A server is expected to disregard or reject any new incoming call that
     has a call number less than the current call number counter.  The call
     number counter for that channel must be advanced to the new call
     number.

     Note that the server cannot just require that the next call that it
     sees on a channel be exactly the call number counter + 1 because then
     there's a scenario that could cause a problem: The client transmits a
     packet to initiate a connection, the network goes out, the server
     sends an ACK (which gets lost), the client sends an ABORT (which also
     gets lost); the network then reconnects, the client then reuses the
     call number for the next call (it doesn't know the server already saw
     the call number), but the server thinks it already has the first
     packet of this call (it doesn't know that the client doesn't know that
     it saw the call number the first time).
Signed-off-by: David Howells <dhowells@redhat.com>

The socket's accept queue (socket->acceptq) should be accessed under
socket->call_lock, not under the connection lock.
Signed-off-by: David Howells <dhowells@redhat.com>

Add RCU destruction for connections and calls as the RCU lookup from the
transport socket data_ready handler is going to come along shortly.

Whilst we're at it, move the cleanup workqueue flushing and RCU barrierage
into the destruction code for the objects that need it (locals and
connections) and add the extra RCU barrier required for connection cleanup.
Signed-off-by: David Howells <dhowells@redhat.com>

When a call is disconnected, clear the call's pointer to the connection and
release the associated ref on that connection.  This means that the call no
longer pins the connection and the connection can be discarded even before
the call is.

As the code currently stands, the call struct is effectively pinned by
userspace until userspace has enacted a recvmsg() to retrieve the final
call state as sk_buffs on the receive queue pin the call to which they're
related because:

 (1) The rxrpc_call struct contains the userspace ID that recvmsg() has to
     include in the control message buffer to indicate which call is being
     referred to.  This ID must remain valid until the terminal packet is
     completely read and must be invalidated immediately at that point as
     userspace is entitled to immediately reuse it.

 (2) The final ACK to the reply to a client call isn't sent until the last
     data packet is entirely read (it's probably worth altering this in
     future to be send the ACK as soon as all the data has been received).


This change requires a bit of rearrangement to make sure that the call
isn't going to try and access the connection again after protocol
completion:

 (1) Delete the error link earlier when we're releasing the call.  Possibly
     network errors should be distributed via connections at the cost of
     adding in an access to the rxrpc_connection struct.

 (2) Remove the call from the connection's call tree before disconnecting
     the call.  The call tree needs to be removed anyway and incoming
     packets delivered by channel pointer instead.

 (3) The release call event should be considered last after all other
     events have been processed so that we don't need access to the
     connection again.

 (4) Move the channel_lock taking from rxrpc_release_call() to
     rxrpc_disconnect_call() where it will be required in future.
Signed-off-by: David Howells <dhowells@redhat.com>

If rxrpc_connect_call() fails during the creation of a client connection,
there are two bugs that we can hit that need fixing:

 (1) The call state should be moved to RXRPC_CALL_DEAD before the call
     cleanup phase is invoked.  If not, this can cause an assertion failure
     later.

 (2) call->link should be reinitialised after being deleted in
     rxrpc_new_client_call() - which otherwise leads to a failure later
     when the call cleanup attempts to delete the link again.
Signed-off-by: David Howells <dhowells@redhat.com>

Rather than calling rxrpc_get_connection() manually before calling
rxrpc_queue_conn(), do it inside the queue wrapper.

This allows us to do some important fixes:

 (1) If the usage count is 0, do nothing.  This prevents connections from
     being reanimated once they're dead.

 (2) If rxrpc_queue_work() fails because the work item is already queued,
     retract the usage count increment which would otherwise be lost.

 (3) Don't take a ref on the connection in the work function.  By passing
     the ref through the work item, this is unnecessary.  Doing it in the
     work function is too late anyway.  Previously, connection-directed
     packets held a ref on the connection, but that's not really the best
     idea.

And another useful changes:

 (*) Don't need to take a refcount on the connection in the data_ready
     handler unless we invoke the connection's work item.  We're using RCU
     there so that's otherwise redundant.
Signed-off-by: David Howells <dhowells@redhat.com>

Check that the client conns cache is empty before module removal and bug if
not, listing any offending connections that are still present.  Unfortunately,
if there are connections still around, then the transport socket is still
unexpectedly open and active, so we can't just unallocate the connections.
Signed-off-by: David Howells <dhowells@redhat.com>

Turn the connection event and state #define lists into enums and move
outside of the struct definition.

Whilst we're at it, change _SERVER to _SERVICE in those identifiers and add
EV_ into the event name to distinguish them from flags and states.

Also add a symbol indicating the number of states and use that in the state
text array.
Signed-off-by: David Howells <dhowells@redhat.com>