Pull 9p update from Dominique Martinet:

 - fix long-standing limitation on open-unlink-fop pattern

 - add refcount to p9_fid (fixes the above and will allow for more
   cleanups and simplifications in the future)

* tag '9p-for-5.11-rc1' of git://github.com/martinetd/linux:
  9p: Remove unnecessary IS_ERR() check
  9p: Uninitialized variable in v9fs_writeback_fid()
  9p: Fix writeback fid incorrectly being attached to dentry
  9p: apply review requests for fid refcounting
  9p: add refcount to p9_fid struct
  fs/9p: search open fids first
  fs/9p: track open fids
  fs/9p: fix create-unlink-getattr idiom

Pull selinux updates from Paul Moore:
 "While we have a small number of SELinux patches for v5.11, there are a
  few changes worth highlighting:

   - Change the LSM network hooks to pass flowi_common structs instead
     of the parent flowi struct as the LSMs do not currently need the
     full flowi struct and they do not have enough information to use it
     safely (missing information on the address family).

     This patch was discussed both with Herbert Xu (representing team
     netdev) and James Morris (representing team
     LSMs-other-than-SELinux).

   - Fix how we handle errors in inode_doinit_with_dentry() so that we
     attempt to properly label the inode on following lookups instead of
     continuing to treat it as unlabeled.

   - Tweak the kernel logic around allowx, auditallowx, and dontauditx
     SELinux policy statements such that the auditx/dontauditx are
     effective even without the allowx statement.

  Everything passes our test suite"

* tag 'selinux-pr-20201214' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  lsm,selinux: pass flowi_common instead of flowi to the LSM hooks
  selinux: Fix fall-through warnings for Clang
  selinux: drop super_block backpointer from superblock_security_struct
  selinux: fix inode_doinit_with_dentry() LABEL_INVALID error handling
  selinux: allow dontauditx and auditallowx rules to take effect without allowx
  selinux: fix error initialization in inode_doinit_with_dentry()

Pull networking updates from Jakub Kicinski:
 "Core:

   - support "prefer busy polling" NAPI operation mode, where we defer
     softirq for some time expecting applications to periodically busy
     poll

   - AF_XDP: improve efficiency by more batching and hindering the
     adjacency cache prefetcher

   - af_packet: make packet_fanout.arr size configurable up to 64K

   - tcp: optimize TCP zero copy receive in presence of partial or
     unaligned reads making zero copy a performance win for much smaller
     messages

   - XDP: add bulk APIs for returning / freeing frames

   - sched: support fragmenting IP packets as they come out of conntrack

   - net: allow virtual netdevs to forward UDP L4 and fraglist GSO skbs

  BPF:

   - BPF switch from crude rlimit-based to memcg-based memory accounting

   - BPF type format information for kernel modules and related tracing
     enhancements

   - BPF implement task local storage for BPF LSM

   - allow the FENTRY/FEXIT/RAW_TP tracing programs to use
     bpf_sk_storage

  Protocols:

   - mptcp: improve multiple xmit streams support, memory accounting and
     many smaller improvements

   - TLS: support CHACHA20-POLY1305 cipher

   - seg6: add support for SRv6 End.DT4/DT6 behavior

   - sctp: Implement RFC 6951: UDP Encapsulation of SCTP

   - ppp_generic: add ability to bridge channels directly

   - bridge: Connectivity Fault Management (CFM) support as is defined
     in IEEE 802.1Q section 12.14.

  Drivers:

   - mlx5: make use of the new auxiliary bus to organize the driver
     internals

   - mlx5: more accurate port TX timestamping support

   - mlxsw:
      - improve the efficiency of offloaded next hop updates by using
        the new nexthop object API
      - support blackhole nexthops
      - support IEEE 802.1ad (Q-in-Q) bridging

   - rtw88: major bluetooth co-existance improvements

   - iwlwifi: support new 6 GHz frequency band

   - ath11k: Fast Initial Link Setup (FILS)

   - mt7915: dual band concurrent (DBDC) support

   - net: ipa: add basic support for IPA v4.5

  Refactor:

   - a few pieces of in_interrupt() cleanup work from Sebastian Andrzej
     Siewior

   - phy: add support for shared interrupts; get rid of multiple driver
     APIs and have the drivers write a full IRQ handler, slight growth
     of driver code should be compensated by the simpler API which also
     allows shared IRQs

   - add common code for handling netdev per-cpu counters

   - move TX packet re-allocation from Ethernet switch tag drivers to a
     central place

   - improve efficiency and rename nla_strlcpy

   - number of W=1 warning cleanups as we now catch those in a patchwork
     build bot

  Old code removal:

   - wan: delete the DLCI / SDLA drivers

   - wimax: move to staging

   - wifi: remove old WDS wifi bridging support"

* tag 'net-next-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1922 commits)
  net: hns3: fix expression that is currently always true
  net: fix proc_fs init handling in af_packet and tls
  nfc: pn533: convert comma to semicolon
  af_vsock: Assign the vsock transport considering the vsock address flags
  af_vsock: Set VMADDR_FLAG_TO_HOST flag on the receive path
  vsock_addr: Check for supported flag values
  vm_sockets: Add VMADDR_FLAG_TO_HOST vsock flag
  vm_sockets: Add flags field in the vsock address data structure
  net: Disable NETIF_F_HW_TLS_TX when HW_CSUM is disabled
  tcp: Add logic to check for SYN w/ data in tcp_simple_retransmit
  net: mscc: ocelot: install MAC addresses in .ndo_set_rx_mode from process context
  nfc: s3fwrn5: Release the nfc firmware
  net: vxget: clean up sparse warnings
  mlxsw: spectrum_router: Use eXtended mezzanine to offload IPv4 router
  mlxsw: spectrum: Set KVH XLT cache mode for Spectrum2/3
  mlxsw: spectrum_router_xm: Introduce basic XM cache flushing
  mlxsw: reg: Add Router LPM Cache Enable Register
  mlxsw: reg: Add Router LPM Cache ML Delete Register
  mlxsw: spectrum_router_xm: Implement L-value tracking for M-index
  mlxsw: reg: Add XM Router M Table Register
  ...

Jakub pointed out that the IP_ECN_set* helpers basically open-code
csum16_add(), so let's switch them over to using the helper instead.

v2:
- Use __be16 for check_add stack variable in IP_ECN_set_ce() (kbot)
v3:
- Turns out we need __force casts to do arithmetic on __be16 types

Reported-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Jonathan Morton <chromatix99@gmail.com>
Tested-by: Pete Heist <pete@heistp.net>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20201211142638.154780-1-toke@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

For each TCP zero window probe, the icsk_backoff is increased by one and
its max value is tcp_retries2. If tcp_retries2 is greater than 63, the
probe0 timeout shift may exceed its max bits. On x86_64/ARMv8/MIPS, the
shift count would be masked to range 0 to 63. And on ARMv7 the result is
zero. If the shift count is masked, only several probes will be sent
with timeout shorter than TCP_RTO_MAX. But if the timeout is zero, it
needs tcp_retries2 times probes to end this false timeout. Besides,
bitwise shift greater than or equal to the width is an undefined
behavior.

This patch adds a limit to the backoff. The max value of max_when is
TCP_RTO_MAX and the min value of timeout base is TCP_RTO_MIN. The limit
is the backoff from TCP_RTO_MIN to TCP_RTO_MAX.

Signed-off-by: Cambda Zhu <cambda@linux.alibaba.com>
Link: https://lore.kernel.org/r/20201208091910.37618-1-cambda@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Because TCP-level resets only affect the subflow, there is a MPTCP
option to indicate that the MPTCP-level connection should be closed
immediately without a mptcp-level fin exchange.

This is the 'MPTCP fast close option'.  It can be carried on ack
segments or TCP resets.  In the latter case, its needed to parse mptcp
options also for reset packets so that MPTCP can act accordingly.

Next patch will add receive side fastclose support in MPTCP.

Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Pull RCU updates from Thomas Gleixner:
 "RCU, LKMM and KCSAN updates collected by Paul McKenney.

  RCU:
   - Avoid cpuinfo-induced IPI pileups and idle-CPU IPIs

   - Lockdep-RCU updates reducing the need for __maybe_unused

   - Tasks-RCU updates

   - Miscellaneous fixes

   - Documentation updates

   - Torture-test updates

  KCSAN:
   - updates for selftests, avoiding setting watchpoints on NULL pointers

   - fix to watchpoint encoding

  LKMM:
   - updates for documentation along with some updates to example-code
     litmus tests"

* tag 'core-rcu-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
  srcu: Take early exit on memory-allocation failure
  rcu/tree: Defer kvfree_rcu() allocation to a clean context
  rcu: Do not report strict GPs for outgoing CPUs
  rcu: Fix a typo in rcu_blocking_is_gp() header comment
  rcu: Prevent lockdep-RCU splats on lock acquisition/release
  rcu/tree: nocb: Avoid raising softirq for offloaded ready-to-execute CBs
  rcu,ftrace: Fix ftrace recursion
  rcu/tree: Make struct kernel_param_ops definitions const
  rcu/tree: Add a warning if CPU being onlined did not report QS already
  rcu: Clarify nocb kthreads naming in RCU_NOCB_CPU config
  rcu: Fix single-CPU check in rcu_blocking_is_gp()
  rcu: Implement rcu_segcblist_is_offloaded() config dependent
  list.h: Update comment to explicitly note circular lists
  rcu: Panic after fixed number of stalls
  x86/smpboot:  Move rcu_cpu_starting() earlier
  rcu: Allow rcu_irq_enter_check_tick() from NMI
  tools/memory-model: Label MP tests' producers and consumers
  tools/memory-model: Use "buf" and "flag" for message-passing tests
  tools/memory-model: Add types to litmus tests
  tools/memory-model: Add a glossary of LKMM terms
  ...

Pull misc fixes from Christian Brauner:
 "This contains several fixes which felt worth being combined into a
  single branch:

   - Use put_nsproxy() instead of open-coding it switch_task_namespaces()

   - Kirill's work to unify lifecycle management for all namespaces. The
     lifetime counters are used identically for all namespaces types.
     Namespaces may of course have additional unrelated counters and
     these are not altered. This work allows us to unify the type of the
     counters and reduces maintenance cost by moving the counter in one
     place and indicating that basic lifetime management is identical
     for all namespaces.

   - Peilin's fix adding three byte padding to Dmitry's
     PTRACE_GET_SYSCALL_INFO uapi struct to prevent an info leak.

   - Two smal patches to convert from the /* fall through */ comment
     annotation to the fallthrough keyword annotation which I had taken
     into my branch and into -next before df561f6688fe ("treewide: Use
     fallthrough pseudo-keyword") made it upstream which fixed this
     tree-wide.

     Since I didn't want to invalidate all testing for other commits I
     didn't rebase and kept them"

* tag 'fixes-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  nsproxy: use put_nsproxy() in switch_task_namespaces()
  sys: Convert to the new fallthrough notation
  signal: Convert to the new fallthrough notation
  time: Use generic ns_common::count
  cgroup: Use generic ns_common::count
  mnt: Use generic ns_common::count
  user: Use generic ns_common::count
  pid: Use generic ns_common::count
  ipc: Use generic ns_common::count
  uts: Use generic ns_common::count
  net: Use generic ns_common::count
  ns: Add a common refcount into ns_common
  ptrace: Prevent kernel-infoleak in ptrace_get_syscall_info()

Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

1) Missing dependencies in NFT_BRIDGE_REJECT, from Randy Dunlap.

2) Use atomic_inc_return() instead of atomic_add_return() in IPVS,
   from Yejune Deng.

3) Simplify check for overquota in xt_nfacct, from Kaixu Xia.

4) Move nfnl_acct_list away from struct net, from Miao Wang.

5) Pass actual sk in reject actions, from Jan Engelhardt.

6) Add timeout and protoinfo to ctnetlink destroy events,
   from Florian Westphal.

7) Four patches to generalize set infrastructure to support
   for multiple expressions per set element.

* git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next:
  netfilter: nftables: netlink support for several set element expressions
  netfilter: nftables: generalize set extension to support for several expressions
  netfilter: nftables: move nft_expr before nft_set
  netfilter: nftables: generalize set expressions support
  netfilter: ctnetlink: add timeout and protoinfo to destroy events
  netfilter: use actual socket sk for REJECT action
  netfilter: nfnl_acct: remove data from struct net
  netfilter: Remove unnecessary conversion to bool
  ipvs: replace atomic_add_return()
  netfilter: nft_reject_bridge: fix build errors due to code movement
====================

Link: https://lore.kernel.org/r/20201212230513.3465-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

On a few of our systems, I found frequent 'unshare(CLONE_NEWNET)' calls
make the number of active slab objects including 'sock_inode_cache' type
rapidly and continuously increase.  As a result, memory pressure occurs.

In more detail, I made an artificial reproducer that resembles the
workload that we found the problem and reproduce the problem faster.  It
merely repeats 'unshare(CLONE_NEWNET)' 50,000 times in a loop.  It takes
about 2 minutes.  On 40 CPU cores / 70GB DRAM machine, the available
memory continuously reduced in a fast speed (about 120MB per second,
15GB in total within the 2 minutes).  Note that the issue don't
reproduce on every machine.  On my 6 CPU cores machine, the problem
didn't reproduce.

'cleanup_net()' and 'fqdir_work_fn()' are functions that deallocate the
relevant memory objects.  They are asynchronously invoked by the work
queues and internally use 'rcu_barrier()' to ensure safe destructions.
'cleanup_net()' works in a batched maneer in a single thread worker,
while 'fqdir_work_fn()' works for each 'fqdir_exit()' call in the
'system_wq'.  Therefore, 'fqdir_work_fn()' called frequently under the
workload and made the contention for 'rcu_barrier()' high.  In more
detail, the global mutex, 'rcu_state.barrier_mutex' became the
bottleneck.

This commit avoids such contention by doing the 'rcu_barrier()' and
subsequent lightweight works in a batched manner, as similar to that of
'cleanup_net()'.  The fqdir hashtable destruction, which is done before
the 'rcu_barrier()', is still allowed to run in parallel for fast
processing, but this commit makes it to use a dedicated work queue
instead of the 'system_wq', to make sure that the number of threads is
bounded.

Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20201211112405.31158-1-sjpark@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>