Use max_1m_mrs/max_8k_mrs while setting max_items, as the former
variables are set based on the underlying device attributes.
Signed-off-by: Avinash Repaka <avinash.repaka@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch fixes the scope of has_fr and has_fmr variables as they are
needed only in rds_ib_add_one().
Signed-off-by: Avinash Repaka <avinash.repaka@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

int rc is unmodified after initalization in net/ipv4/route.c, this patch simply cleans up that variable and returns 0.

This was found with coccicheck M=net/ipv4/ on linus' tree.
Signed-off-by: Tim Hansen <devtimhansen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This commit does a cleanup and moves tcp_rearm_rto() call in the TFO
server case into a previous spot in tcp_rcv_state_process() to make
it more compact.
This is only a cosmetic change.
Suggested-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Wei Wang <weiwan@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Currently in the TCP code, the initialization sequence for cached
metrics, congestion control, BPF, etc, after successful connection
is very inconsistent. This introduces inconsistent bevhavior and is
prone to bugs. The current call sequence is as follows:

(1) for active case (tcp_finish_connect() case):
        tcp_mtup_init(sk);
        icsk->icsk_af_ops->rebuild_header(sk);
        tcp_init_metrics(sk);
        tcp_call_bpf(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB);
        tcp_init_congestion_control(sk);
        tcp_init_buffer_space(sk);

(2) for passive case (tcp_rcv_state_process() TCP_SYN_RECV case):
        icsk->icsk_af_ops->rebuild_header(sk);
        tcp_call_bpf(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
        tcp_init_congestion_control(sk);
        tcp_mtup_init(sk);
        tcp_init_buffer_space(sk);
        tcp_init_metrics(sk);

(3) for TFO passive case (tcp_fastopen_create_child()):
        inet_csk(child)->icsk_af_ops->rebuild_header(child);
        tcp_init_congestion_control(child);
        tcp_mtup_init(child);
        tcp_init_metrics(child);
        tcp_call_bpf(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
        tcp_init_buffer_space(child);

This commit uniforms the above functions to have the following sequence:
        tcp_mtup_init(sk);
        icsk->icsk_af_ops->rebuild_header(sk);
        tcp_init_metrics(sk);
        tcp_call_bpf(sk, BPF_SOCK_OPS_ACTIVE/PASSIVE_ESTABLISHED_CB);
        tcp_init_congestion_control(sk);
        tcp_init_buffer_space(sk);
This sequence is the same as the (1) active case. We pick this sequence
because this order correctly allows BPF to override the settings
including congestion control module and initial cwnd, etc from
the route, and then allows the CC module to see those settings.
Suggested-by: Neal Cardwell <ncardwell@google.com>
Tested-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Wei Wang <weiwan@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stefan Hajnoczi says:

====================
VSOCK: add sock_diag interface

v3:
 * Rebased onto net-next/master and resolved Hyper-V transport conflict

v2:
 * Moved tests to tools/testing/vsock/.  I was unable to put them in selftests/
   because they require manual setup of a VMware/KVM guest.
 * Moved to __vsock_in_bound/connected_table() to af_vsock.h
 * Fixed local variable ordering in Patch 4

There is currently no way for userspace to query open AF_VSOCK sockets.  This
means ss(8), netstat(8), and other utilities cannot display AF_VSOCK sockets.

This patch series adds the netlink sock_diag interface for AF_VSOCK.  Userspace
programs sent a DUMP request including an sk_state bitmap to filter sockets
based on their state (connected, listening, etc).  The vsock_diag.ko module
replies with information about matching sockets.  This userspace ABI is defined
in <linux/vm_sockets_diag.h>.

The final patch adds a test suite that exercises the basic cases.

Jorgen and Dexuan: I have only tested the virtio transport but this should also
work for VMCI and Hyper-V.  Please give it a shot if you have time.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch adds tests for the vsock_diag.ko module.

These tests are not self-tests because they require manual set up of a
KVM or VMware guest.  Please see tools/testing/vsock/README for
instructions.

The control.h and timeout.h infrastructure can be used for additional
AF_VSOCK tests in the future.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch adds the sock_diag interface for querying sockets from
userspace.  Tools like ss(8) and netstat(8) can use this interface to
list open sockets.

The userspace ABI is defined in <linux/vm_sockets_diag.h> and includes
netlink request and response structs.  The request can query sockets
based on their sk_state (e.g. listening sockets only) and the response
contains socket information fields including the local/remote addresses,
inode number, etc.

This patch does not dump VMCI pending sockets because I have only tested
the virtio transport, which does not use pending sockets.  Support can
be added later by extending vsock_diag_dump() if needed by VMCI users.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There are two state fields: socket->state and sock->sk_state.  The
socket->state field uses SS_UNCONNECTED, SS_CONNECTED, etc while the
sock->sk_state typically uses values that match TCP state constants
(TCP_CLOSE, TCP_ESTABLISHED).  AF_VSOCK does not follow this convention
and instead uses SS_* constants for both fields.

The sk_state field will be exposed to userspace through the vsock_diag
interface for ss(8), netstat(8), and other programs.

This patch switches sk_state to TCP state constants so that the meaning
of this field is consistent with other address families.  Not just
AF_INET and AF_INET6 use the TCP constants, AF_UNIX and others do too.

The following mapping was used to convert the code:

  SS_FREE -> TCP_CLOSE
  SS_UNCONNECTED -> TCP_CLOSE
  SS_CONNECTING -> TCP_SYN_SENT
  SS_CONNECTED -> TCP_ESTABLISHED
  SS_DISCONNECTING -> TCP_CLOSING
  VSOCK_SS_LISTEN -> TCP_LISTEN

In __vsock_create() the sk_state initialization was dropped because
sock_init_data() already initializes sk_state to TCP_CLOSE.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The vsock_diag.ko module will need to check socket table membership.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The socket table symbols need to be exported from vsock.ko so that the
vsock_diag.ko module will be able to traverse sockets.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Just simple overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull power management fix from Rafael Wysocki:
 "This fixes a code ordering issue in the main suspend-to-idle loop that
  causes some "low power S0 idle" conditions to be incorrectly reported
  as unmet with suspend/resume debug messages enabled"

* tag 'pm-4.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / s2idle: Invoke the ->wake() platform callback earlier

* pm-sleep:
  PM / s2idle: Invoke the ->wake() platform callback earlier

Merge tag 'for-4.14/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - a stable fix for the alignment of the event number reported at the
   end of the 'DM_LIST_DEVICES' ioctl.

 - a couple stable fixes for the DM crypt target.

 - a DM raid health status reporting fix.

* tag 'for-4.14/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm raid: fix incorrect status output at the end of a "recover" process
  dm crypt: reject sector_size feature if device length is not aligned to it
  dm crypt: fix memory leak in crypt_ctr_cipher_old()
  dm ioctl: fix alignment of event number in the device list

There are three important fields that indicate the overall health and
status of an array: dev_health, sync_ratio, and sync_action.  They tell
us the condition of the devices in the array, and the degree to which
the array is synchronized.

This commit fixes a condition that is reported incorrectly.  When a member
of the array is being rebuilt or a new device is added, the "recover"
process is used to synchronize it with the rest of the array.  When the
process is complete, but the sync thread hasn't yet been reaped, it is
possible for the state of MD to be:
 mddev->recovery = [ MD_RECOVERY_RUNNING MD_RECOVERY_RECOVER MD_RECOVERY_DONE ]
 curr_resync_completed = <max dev size> (but not MaxSector)
 and all rdevs to be In_sync.
This causes the 'array_in_sync' output parameter that is passed to
rs_get_progress() to be computed incorrectly and reported as 'false' --
or not in-sync.  This in turn causes the dev_health status characters to
be reported as all 'a', rather than the proper 'A'.

This can cause erroneous output for several seconds at a time when tools
will want to be checking the condition due to events that are raised at
the end of a sync process.  Fix this by properly calculating the
'array_in_sync' return parameter in rs_get_progress().

Also, remove an unnecessary intermediate 'recovery_cp' variable in
rs_get_progress().
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Pull sound fixes from Takashi Iwai:
 "A collection of small fixes, mostly with stable ones:

 - X32 ABI fix for PCM; likely not so many people suffer from it, but
   still better to fix

 - Two minor kernel warning fixes on USB audio devices spotted by
   syzkaller

 - Regression fix of echoaudio due to its inconsistent dimension

 - Fix for HBR support on Intel DP audio, on some recent chips

 - USB-audio quirk for yet another Plantronics devices

 - Fix for potential double-fetch in ASIHPI FIFO queue"

* tag 'sound-4.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usx2y: Suppress kernel warning at page allocation failures
  Revert "ALSA: echoaudio: purge contradictions between dimension matrix members and total number of members"
  ALSA: usb-audio: Check out-of-bounds access by corrupted buffer descriptor
  ALSA: pcm: Fix structure definition for X32 ABI
  ALSA: usb-audio: Add sample rate quirk for Plantronics C310/C520-M
  ALSA: hda - program ICT bits to support HBR audio
  ALSA: asihpi: fix a potential double-fetch bug when copying puhm
  ALSA: compress: Remove unused variable

Pull HID subsystem fixes from Jiri Kosina:

 - buffer management size fix for i2c-hid driver, from Adrian Salido

 - tool ID regression fixes for Wacom driver from Jason Gerecke

 - a few small assorted fixes and a few device ID additions

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  Revert "HID: multitouch: Support ALPS PTP stick with pid 0x120A"
  HID: hidraw: fix power sequence when closing device
  HID: wacom: Always increment hdev refcount within wacom_get_hdev_data
  HID: wacom: generic: Clear ABS_MISC when tool leaves proximity
  HID: wacom: generic: Send MSC_SERIAL and ABS_MISC when leaving prox
  HID: i2c-hid: allocate hid buffers for real worst case
  HID: rmi: Make sure the HID device is opened on resume
  HID: multitouch: Support ALPS PTP stick with pid 0x120A
  HID: multitouch: support buttons and trackpoint on Lenovo X1 Tab Gen2
  HID: wacom: Correct coordinate system of touchring and pen twist
  HID: wacom: Properly report negative values from Intuos Pro 2 Bluetooth
  HID: multitouch: Fix system-control buttons not working
  HID: add multi-input quirk for IDC6680 touchscreen
  HID: wacom: leds: Don't try to control the EKR's read-only LEDs
  HID: wacom: bits shifted too much for 9th and 10th buttons

Pull networking fixes from David Miller:

 1) Check iwlwifi 9000 reorder buffer out-of-space condition properly,
    from Sara Sharon.

 2) Fix RCU splat in qualcomm rmnet driver, from Subash Abhinov
    Kasiviswanathan.

 3) Fix session and tunnel release races in l2tp, from Guillaume Nault
    and Sabrina Dubroca.

 4) Fix endian bug in sctp_diag_dump(), from Dan Carpenter.

 5) Several mlx5 driver fixes from the Mellanox folks (max flow counters
    cap check, invalid memory access in IPoIB support, etc.)

 6) tun_get_user() should bail if skb->len is zero, from Alexander
    Potapenko.

 7) Fix RCU lookups in inetpeer, from Eric Dumazet.

 8) Fix locking in packet_do_bund().

 9) Handle cb->start() error properly in netlink dump code, from Jason
    A. Donenfeld.

10) Handle multicast properly in UDP socket early demux code. From Paolo
    Abeni.

11) Several erspan bug fixes in ip_gre, from Xin Long.

12) Fix use-after-free in socket filter code, in order to handle the
    fact that listener lock is no longer taken during the three-way TCP
    handshake. From Eric Dumazet.

13) Fix infoleak in RTM_GETSTATS, from Nikolay Aleksandrov.

14) Fix tail call generation in x86-64 BPF JIT, from Alexei Starovoitov.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (77 commits)
  net: 8021q: skip packets if the vlan is down
  bpf: fix bpf_tail_call() x64 JIT
  net: stmmac: dwmac-rk: Add RK3128 GMAC support
  rndis_host: support Novatel Verizon USB730L
  net: rtnetlink: fix info leak in RTM_GETSTATS call
  socket, bpf: fix possible use after free
  mlxsw: spectrum_router: Track RIF of IPIP next hops
  mlxsw: spectrum_router: Move VRF refcounting
  net: hns3: Fix an error handling path in 'hclge_rss_init_hw()'
  net: mvpp2: Fix clock resource by adding an optional bus clock
  r8152: add Linksys USB3GIGV1 id
  l2tp: fix l2tp_eth module loading
  ip_gre: erspan device should keep dst
  ip_gre: set tunnel hlen properly in erspan_tunnel_init
  ip_gre: check packet length and mtu correctly in erspan_xmit
  ip_gre: get key from session_id correctly in erspan_rcv
  tipc: use only positive error codes in messages
  ppp: fix __percpu annotation
  udp: perform source validation for mcast early demux
  IPv4: early demux can return an error code
  ...

Jakub Kicinski says:

====================
tools: add bpftool

This set adds bpftool to the tools/ directory.  The first
patch renames tools/net to tools/bpf, the second one adds
the new code, while the third adds simple documentation.

v4:
 - rename docs *.txt -> *.rst (Jesper).
v3:
 - address Alexei's comments about output and docs.
v2:
 - report names, map ids, load time, uid;
 - add docs/man pages;
 - general cleanups & fixes.
====================
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add documentation for bpftool.  Separate files for each subcommand.
Use rst format.  Documentation is compiled into man pages using
rst2man.
Signed-off-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add a simple tool for querying and updating BPF objects on the system.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

We currently only have BPF tools in the tools/net directory.
We are about to add more BPF tools there, not necessarily
networking related, rename the directory and related Makefile
targets to bpf.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

David Ahern says:

====================
net: Plumb extack error reporting to enslavements

Another round of extending extack error reporting, this time for
enslavements through ndo_add_slave and notifiers.

v2
- changed how the messages are added to bonding driver per Jiri's request
- fixed spectrum message for LAG overflow per Ido's comment
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

mlxsw fails device enslavement for a number of reasons. Use the extack
facility to return an error message to the user stating why the enslave
is failing.

Messages are prefixed with "spectrum" so users know it is a constraint
imposed by the hardware driver. For example:
    $ ip li add br0.11 link br0 type vlan id 11
    $ ip li set swp11 master br0
    Error: spectrum: Enslaving a port to a device that already has an upper device is not supported.
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pass extack arg to br_add_if. Add messages for a couple of failures
and pass arg to netdev_master_upper_dev_link.
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

A number of bond_enslave errors are logged using the netdev_err API.
Return those messages to userspace via the extack facility.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add extack arg to netdev_upper_dev_link and netdev_master_upper_dev_link
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pass extack to do_set_master and down to ndo_add_slave
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add netlink_ext_ack to netdev_notifier_info to allow notifier
handlers to return errors to userspace.

Clean up the initialization in dev.c such that extack is easily
added in subsequent patches where relevant. Specifically, remove
the init call in call_netdevice_notifiers_info and have callers
initalize on stack when info is declared.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If the vlan is down, free the packet instead of proceeding with other
processing, or counting it as received.  If vlan interfaces are used
as slaves for bonding, with arp monitoring for connectivity, if the rx
counter is seen to be incrementing, then the bond device will not
observe that the interface is down.

CC: David S. Miller <davem@davemloft.net>
Signed-off-by: Vishakha Narvekar <Vishakha.Narvekar@dell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

x-netns interfaces are bound to two netns: the link netns and the upper
netns. Usually, this kind of interfaces is created in the link netns and
then moved to the upper netns. At the end, the interface is visible only
in the upper netns. The link nsid is advertised via netlink in the upper
netns, thus the user always knows where is the link part.

There is no such mechanism in the link netns. When the interface is moved
to another netns, the user cannot "follow" it.
This patch adds a new netlink attribute which helps to follow an interface
which moves to another netns. When the interface is unregistered, the new
nsid is advertised. If the interface is a x-netns interface (ie
rtnl_link_ops->get_link_net is defined), the nsid is allocated if needed.

CC: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull ARM SoC fixes from Olof Johansson:
 "Our first batch of fixes this release cycle, unfortunately a bit
  noisier than usual. Two major groups stand out:

   - Some pinctril dts/dtsi changes for stm32 due to a new driver being
     merged during the merge window, and this aligns the DT contents
     between the old format and the new. This could arguably be moved to
     the next merge window but it also seemed relatively harmless to
     include now.

   - Amlogic/meson had driver changes merged that required devicetree
     changes to avoid functional/performance regressions. I've already
     asked them to be more careful about this going forward, and making
     sure drivers are compatible with older DTs when they make these
     kind of changes. The platform is actively being upstreamed so
     there's a few things in flight, we've seen this happen before and
     sometimes it's hard to catch in time.

  Besides that there is the usual mix of minor fixes"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (33 commits)
  ARM: dts: stm32: use right pinctrl compatible for stm32f469
  ARM: dts: stm32: Fix STMPE1600 binding on stm32429i-eval board
  ARM: defconfig: update Gemini defconfig
  ARM: defconfig: FRAMEBUFFER_CONSOLE can no longer be =m
  arm64: dts: rockchip: add the grf clk for dw-mipi-dsi on rk3399
  reset: Restrict RESET_HSDK to ARC_SOC_HSDK or COMPILE_TEST
  ARM: dts: da850-evm: add serial and ethernet aliases
  ARM: dts: am43xx-epos-evm: Remove extra CPSW EMAC entry
  ARM: dts: am33xx: Add spi alias to match SOC schematics
  ARM: OMAP2+: hsmmc: fix logic to call either omap_hsmmc_init or omap_hsmmc_late_init but not both
  ARM: dts: dra7: Set a default parent to mcasp3_ahclkx_mux
  ARM: OMAP2+: dra7xx: Set OPT_CLKS_IN_RESET flag for gpio1
  ARM: dts: nokia n900: drop unneeded/undocumented parts of the dts
  arm64: dts: rockchip: Correct MIPI DPHY PLL clock on rk3399
  arm64: dt marvell: Fix AP806 system controller size
  MAINTAINERS: add Macchiatobin maintainers entry
  ARC: reset: remove the misleading v1 suffix all over
  ARC: reset: add missing DT binding documentation for HSDKv1 reset driver
  ARC: reset: Only build on archs that have IOMEM
  ARM: at91: Replace uses of virt_to_phys with __pa_symbol
  ...

Update my imgtec.com and personal email address to my kernel.org one in
a few places as MIPS will soon no longer be part of Imagination
Technologies, and add mappings in .mailcap so get_maintainer.pl reports
the right address.
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Alexei Starovoitov says:

====================
bpf: muli prog support for cgroup-bpf

v1->v2:
- fixed accidentally swapped two lines which caused static_key not going to zero
- addressed Martin's feedback and changed prog_query to be consistent
  with verifier output: return -enospc and fill supplied buffer instead
  of just returning -enospc when buffer is too small to fit all prog_ids

v1:
cgroup-bpf use cases are getting more advanced and running only
one program per cgroup is no longer enough. Therefore introduce
support for attaching multiple programs per cgroup and running
a set of effective programs.

These patches introduces BPF_F_ALLOW_MULTI flag for BPF_PROG_ATTACH cmd.
The default is still NONE and behavior of BPF_F_ALLOW_OVERRIDE flag
is unchanged.
The difference between three possible flags for BPF_PROG_ATTACH command:
- NONE(default): No further bpf programs allowed in the subtree.
- BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
  the program in this cgroup yields to sub-cgroup program.
- BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
  that cgroup program gets run in addition to the program in this cgroup.

Most of the logic is in patch 1. Even when cgroup doesn't have
any programs attached its set of effective program can be non-empty.
To quickly execute them and avoid penalizing cgroups without
any effective programs introduce 'struct bpf_prog_array'
which has an optimization for cgroups with zero effective programs.

Patch 2 introduces BPF_PROG_QUERY command for introspection
Patch 3 makes verifier more strict for cgroup-bpf program types.
Patch 4+ are tests.

More details in individual patches
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

use BPF_PROG_QUERY command to strengthen test coverage
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

add support for BPF_PROG_QUERY command to libbpf
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/include/uapi/linux/bpf.h got out of sync with actual kernel header.
Update it.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

create 5 cgroups, attach 6 progs and check that progs are executed as:
cgrp1 (MULTI progs A, B) ->
   cgrp2 (OVERRIDE prog C) ->
     cgrp3 (MULTI prog D) ->
       cgrp4 (OVERRIDE prog E) ->
         cgrp5 (NONE prog F)
the event in cgrp5 triggers execution of F,D,A,B in that order.
if prog F is detached, the execution is E,D,A,B
if prog F and D are detached, the execution is E,A,B
if prog F, E and D are detached, the execution is C,A,B
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>