Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:

       ret = rhashtable_walk_start(rhiter);
       if (ret && ret != -EAGAIN)
               goto out;

Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.

This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.
Signed-off-by: Tom Herbert <tom@quantonium.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fixes: 46e6b992 ("rtnetlink: allow GSO maximums to be set on device creation")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflict was two parallel additions of include files to sch_generic.c,
no biggie.
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 4675ff05 ("kmemcheck: rip it out") has removed the code but
for some reason SPDX header stayed in place.  This looks like a rebase
mistake in the mmotm tree or the merge mistake.  Let's drop those
leftovers as well.
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull networking fixes from David Miller:

 1) CAN fixes from Martin Kelly (cancel URBs properly in all the CAN usb
    drivers).

 2) Revert returning -EEXIST from __dev_alloc_name() as this propagates
    to userspace and broke some apps. From Johannes Berg.

 3) Fix conn memory leaks and crashes in TIPC, from Jon Malloc and Cong
    Wang.

 4) Gianfar MAC can't do EEE so don't advertise it by default, from
    Claudiu Manoil.

 5) Relax strict netlink attribute validation, but emit a warning. From
    David Ahern.

 6) Fix regression in checksum offload of thunderx driver, from Florian
    Westphal.

 7) Fix UAPI bpf issues on s390, from Hendrik Brueckner.

 8) New card support in iwlwifi, from Ihab Zhaika.

 9) BBR congestion control bug fixes from Neal Cardwell.

10) Fix port stats in nfp driver, from Pieter Jansen van Vuuren.

11) Fix leaks in qualcomm rmnet, from Subash Abhinov Kasiviswanathan.

12) Fix DMA API handling in sh_eth driver, from Thomas Petazzoni.

13) Fix spurious netpoll warnings in bnxt_en, from Calvin Owens.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (67 commits)
  net: mvpp2: fix the RSS table entry offset
  tcp: evaluate packet losses upon RTT change
  tcp: fix off-by-one bug in RACK
  tcp: always evaluate losses in RACK upon undo
  tcp: correctly test congestion state in RACK
  bnxt_en: Fix sources of spurious netpoll warnings
  tcp_bbr: reset long-term bandwidth sampling on loss recovery undo
  tcp_bbr: reset full pipe detection on loss recovery undo
  tcp_bbr: record "full bw reached" decision in new full_bw_reached bit
  sfc: pass valid pointers from efx_enqueue_unwind
  gianfar: Disable EEE autoneg by default
  tcp: invalidate rate samples during SACK reneging
  can: peak/pcie_fd: fix potential bug in restarting tx queue
  can: usb_8dev: cancel urb on -EPIPE and -EPROTO
  can: kvaser_usb: cancel urb on -EPIPE and -EPROTO
  can: esd_usb2: cancel urb on -EPIPE and -EPROTO
  can: ems_usb: cancel urb on -EPIPE and -EPROTO
  can: mcba_usb: cancel urb on -EPROTO
  usbnet: fix alignment for frames with no ethernet header
  tcp: use current time in tcp_rcv_space_adjust()
  ...

Pull media fixes from Mauro Carvalho Chehab:

 "A series of fixes for the media subsytem:

   - The largest amount of fixes in this series is with regards to
     comments that aren't kernel-doc, but start with "/**".

     A new check added for 4.15 makes it to produce a *huge* amount of
     new warnings (I'm compiling here with W=1). Most of the patches in
     this series fix those.

     No code changes - just comment changes at the source files

   - rc: some fixed in order to better handle RC repetition codes

   - v4l-async: use the v4l2_dev from the root notifier when matching
     sub-devices

   - v4l2-fwnode: Check subdev count after checking port

   - ov 13858 and et8ek8: compilation fix with randconfigs

   - usbtv: a trivial new USB ID addition

   - dibusb-common: don't do DMA on stack on firmware load

   - imx274: Fix error handling, add MAINTAINERS entry

   - sir_ir: detect presence of port"

* tag 'media/v4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (50 commits)
  media: imx274: Fix error handling, add MAINTAINERS entry
  media: v4l: async: use the v4l2_dev from the root notifier when matching sub-devices
  media: v4l2-fwnode: Check subdev count after checking port
  media: et8ek8: select V4L2_FWNODE
  media: ov13858: Select V4L2_FWNODE
  media: rc: partial revert of "media: rc: per-protocol repeat period"
  media: dvb: i2c transfers over usb cannot be done from stack
  media: dvb-frontends: complete kernel-doc markups
  media: docs: add documentation for frontend attach info
  media: dvb_frontends: fix kernel-doc macros
  media: drivers: remove "/**" from non-kernel-doc comments
  media: lm3560: add a missing kernel-doc parameter
  media: rcar_jpu: fix two kernel-doc markups
  media: vsp1: add a missing kernel-doc parameter
  media: soc_camera: fix a kernel-doc markup
  media: mt2063: fix some kernel-doc warnings
  media: radio-wl1273: fix a parameter name at kernel-doc macro
  media: s3c-camif: add missing description at s3c_camif_find_format()
  media: mtk-vpu: add description for wdt fields at struct mtk_vpu
  media: vdec: fix some kernel-doc warnings
  ...

Pull drm fixes from Dave Airlie:
 "This pull is a bit larger than I'd like but a large bunch of it is
  license fixes, AMD wanted to fix the licenses for a bunch of files
  that were missing them,

 Otherwise a bunch of TTM regression fix since the hugepage support,
 some i915 and gvt fixes, a core connector free in a safe context fix,
 and one bridge fix"

* tag 'drm-fixes-for-v4.15-rc3' of git://people.freedesktop.org/~airlied/linux: (26 commits)
  drm/bridge: analogix dp: Fix runtime PM state in get_modes() callback
  Revert "drm/i915: Display WA #1133 WaFbcSkipSegments:cnl, glk"
  drm/vc4: Fix false positive WARN() backtrace on refcount_inc() usage
  drm/i915: Call i915_gem_init_userptr() before taking struct_mutex
  drm/exynos: remove unnecessary function declaration
  drm/exynos: remove unnecessary descrptions
  drm/exynos: gem: Drop NONCONTIG flag for buffers allocated without IOMMU
  drm/exynos: Fix dma-buf import
  drm/ttm: swap consecutive allocated pooled pages v4
  drm: safely free connectors from connector_iter
  drm/i915/gvt: set max priority for gvt context
  drm/i915/gvt: Don't mark vgpu context as inactive when preempted
  drm/i915/gvt: Limit read hw reg to active vgpu
  drm/i915/gvt: Export intel_gvt_render_mmio_to_ring_id()
  drm/i915/gvt: Emulate PCI expansion ROM base address register
  drm/ttm: swap consecutive allocated cached pages v3
  drm/ttm: roundup the shrink request to prevent skip huge pool
  drm/ttm: add page order support in ttm_pages_put
  drm/ttm: add set_pages_wb for handling page order more than zero
  drm/ttm: add page order in page pool
  ...

Pull md fixes from Shaohua Li:
 "Some MD fixes.

  The notable one is a raid5-cache deadlock bug with dm-raid, others are
  not significant"

* tag 'md/4.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  md/raid1/10: add missed blk plug
  md: limit mdstat resync progress to max_sectors
  md/r5cache: move mddev_lock() out of r5c_journal_mode_set()
  md/raid5: correct degraded calculation in raid5_error

Merge tag 'devicetree-fixes-for-4.15-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull DeviceTree fixes from Rob Herring:
 "Another set of DT fixes:

   - Fixes from overlay code rework. A trifecta of fixes to the locking,
     an out of bounds access, and a memory leak in of_overlay_apply()

   - Clean-up at25 eeprom binding document

   - Remove leading '0x' in unit-addresses from binding docs"

* tag 'devicetree-fixes-for-4.15-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  of: overlay: Make node skipping in init_overlay_changeset() clearer
  of: overlay: Fix out-of-bounds write in init_overlay_changeset()
  of: overlay: Fix (un)locking in of_overlay_apply()
  of: overlay: Fix memory leak in of_overlay_apply() error path
  dt-bindings: eeprom: at25: Document device-specific compatible values
  dt-bindings: eeprom: at25: Grammar s/are can/can/
  dt-bindings: Remove leading 0x from bindings notation
  of: overlay: Remove else after goto
  of: Spelling s/changset/changeset/
  of: unittest: Remove bogus overlay mutex release from overlay_data_add()

Pull virtio bugfixes from Michael Tsirkin:
 "A couple of minor bugfixes"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_net: fix return value check in receive_mergeable()
  virtio_mmio: add cleanup for virtio_mmio_remove
  virtio_mmio: add cleanup for virtio_mmio_probe

Pull xen fixes from Juergen Gross:
 "Just two small fixes for the new pvcalls frontend driver"

* tag 'for-linus-4.15-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pvcalls: Fix a check in pvcalls_front_remove()
  xen/pvcalls: check for xenbus_read() errors

Pull powerpc fixes from Michael Ellerman:

 "One notable fix for kexec on Power9, where we were not clearing MMU
  PID properly which sometimes leads to hangs. Finally debugged to a
  root cause by Nick.

  A revert of a patch which tried to rework our panic handling to get
  more output on the console, but inadvertently broke reporting the
  panic to the hypervisor, which apparently people care about.

  Then a fix for an oops in the PMU code, and finally some s/%p/%px/ in
  xmon.

  Thanks to: David Gibson, Nicholas Piggin, Ravi Bangoria"

* tag 'powerpc-4.15-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/xmon: Don't print hashed pointers in xmon
  powerpc/64s: Initialize ISAv3 MMU registers before setting partition table
  Revert "powerpc: Do not call ppc_md.panic in fadump panic notifier"
  powerpc/perf: Fix oops when grouping different pmu events

Merge tag 'linux-can-fixes-for-4.15-20171208' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2017-12-08

this is a pull request of 6 patches for net/master.

Martin Kelly provides 5 patches for various USB based CAN drivers, that
properly cancel the URBs on adapter unplug, so that the driver doesn't
end up in an endless loop. Stephane Grosjean provides a patch to restart
the tx queue if zero length packages are transmitted.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Move 'macaddr_count' from after 'netpoll' to after 'nest_level' to pack
and reduce a memory hole.

Fixes: 88ca59d1 (macvlan: remove unused fields in struct macvlan_dev)
Signed-off-by: Girish Moodalbail <girish.moodalbail@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'wireless-drivers-for-davem-2017-12-08' of git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers

Kalle Valo says:

====================
wireless-drivers fixes for 4.15

Second set of fixes for 4.15. This time a lot of iwlwifi patches and
two brcmfmac patches. Most important here are the MIC and IVC fixes
for iwlwifi to unbreak 9000 series.

iwlwifi

* fix rate-scaling to not start lowest possible rate

* fix the TX queue hang detection for AP/GO modes

* fix the TX queue hang timeout in monitor interfaces

* fix packet injection

* remove a wrong error message when dumping PCI registers

* fix race condition with RF-kill

* tell mac80211 when the MIC has been stripped (9000 series)

* tell mac80211 when the IVC has been stripped (9000 series)

* add 2 new PCI IDs, one for 9000 and one for 22000

* fix a queue hang due during a P2P Remain-on-Channel operation

brcmfmac

* fix a race which sometimes caused a crash during sdio unbind

* fix a kernel-doc related build error
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

The first and only parameter of sl_alloc() is unused, so remove it.

Fixes: 5342b77c slip: ("Clean up create and destroy")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

The macro used to access or set an RSS table entry was using an offset
of 8, while it should use an offset of 0. This lead to wrongly configure
the RSS table, not accessing the right entries.

Fixes: 1d7d15d7 ("net: mvpp2: initialize the RSS tables")
Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Rahul Lakkireddy says:

====================
cxgb4: collect hardware logs via ethtool

Collect more hardware logs via ethtool --get-dump facility.

Patch 1 collects on-chip memory layout information.

Patch 2 collects on-chip MC memory dumps.

Patch 3 collects HMA memory dump.

Patch 4 evaluates and skips TX and RX payload regions in memory dumps.

Patch 5 collects egress and ingress SGE queue contexts.

Patch 6 collects PCIe configuration logs
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use meminfo to identify the egress and ingress context regions and
fetch all valid contexts from those regions. Also flush all contexts
before attempting collection to prevent stale information.
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use meminfo to identify TX and RX payload regions and skip them in
collection of EDC, MC, and HMA.
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use meminfo to get base address and size of MC memory.  Also use same
meminfo for EDC memory dumps.
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Collect memory layout of various on-chip memory regions.  Move code
for collecting on-chip memory information to cudbg_lib.c and update
cxgb4_debugfs.c to use the common function.  Also include
cudbg_entity.h before cudbg_lib.h to avoid adding cudbg entity
structure forward declarations in cudbg_lib.h.
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stephen Hemminger says:

====================
veth and GSO maximums

This is the more general way to solving the issue of GSO limits
not being set correctly for containers on Azure. If a GSO packet
is sent to host that exceeds the limit (reported by NDIS), then
the host is forced to do segmentation in software which has noticeable
performance impact.

The core rtnetlink infrastructure already has the messages and
infrastructure to allow changing gso limits. With an updated iproute2
the following already works:
  # ip li set dev dummy0 gso_max_size 30000

These patches are about making it easier with veth.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

When new veth is created, and GSO values have been configured
on one device, clone those values to the peer.

For example:
   # ip link add dev vm1 gso_max_size 65530 type veth peer name vm2

This should create vm1 <--> vm2 with both having GSO maximum
size set to 65530.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Netlink device already allows changing GSO sizes with
ip set command. The part that is missing is allowing overriding
GSO settings on device creation.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

There is nothing that says that number of TX queues == number of RX
queues. E.g. the ARTPEC-6 SoC has 2 TX queues and 1 RX queue.

This code is obviously wrong:
for (chan = 0; chan < tx_channel_count; chan++) {
    struct stmmac_rx_queue *rx_q = &priv->rx_queue[chan];

priv->rx_queue has size MTL_MAX_RX_QUEUES, so this will send an
uninitialized napi_struct to __napi_schedule(), causing us to
crash in net_rx_action(), because napi_struct->poll is zero.

[12846.759880] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[12846.768014] pgd = (ptrval)
[12846.770742] [00000000] *pgd=39ec7831, *pte=00000000, *ppte=00000000
[12846.777023] Internal error: Oops: 80000007 [#1] PREEMPT SMP ARM
[12846.782942] Modules linked in:
[12846.785998] CPU: 0 PID: 161 Comm: dropbear Not tainted 4.15.0-rc2-00285-gf5fb5f2f39a7 #36
[12846.794177] Hardware name: Axis ARTPEC-6 Platform
[12846.798879] task: (ptrval) task.stack: (ptrval)
[12846.803407] PC is at 0x0
[12846.805942] LR is at net_rx_action+0x274/0x43c
[12846.810383] pc : [<00000000>]    lr : [<80bff064>]    psr: 200e0113
[12846.816648] sp : b90d9ae8  ip : b90d9ae8  fp : b90d9b44
[12846.821871] r10: 00000008  r9 : 0013250e  r8 : 00000100
[12846.827094] r7 : 0000012c  r6 : 00000000  r5 : 00000001  r4 : bac84900
[12846.833619] r3 : 00000000  r2 : b90d9b08  r1 : 00000000  r0 : bac84900

Since each DMA channel can be used for rx and tx simultaneously,
the current code should probably be rewritten so that napi_struct is
embedded in a new struct stmmac_channel.
That way, stmmac_poll() can call stmmac_tx_clean() on just the tx queue
where we got the IRQ, instead of looping through all tx queues.
This is also how the xgbe driver does it (another driver for this IP).

Fixes: c22a3f48 ("net: stmmac: adding multiple napi mechanism")
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Yuchung Cheng says:

====================
tcp: RACK loss recovery bug fixes

This patch set has four minor bug fixes in TCP RACK loss recovery.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

RACK skips an ACK unless it advances the most recently delivered
TX timestamp (rack.mstamp). Since RACK also uses the most recent
RTT to decide if a packet is lost, RACK should still run the
loss detection whenever the most recent RTT changes. For example,
an ACK that does not advance the timestamp but triggers the cwnd
undo due to reordering, would then use the most recent (higher)
RTT measurement to detect further losses.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

RACK should mark a packet lost when remaining wait time is zero.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When sender detects spurious retransmission, all packets
marked lost are remarked to be in-flight. However some may
be considered lost based on its timestamps in RACK. This patch
forces RACK to re-evaluate, which may be skipped previously if
the ACK does not advance RACK timestamp.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

RACK does not test the loss recovery state correctly to compute
the reordering window. It assumes if lost_out is zero then TCP is
not in loss recovery. But it can be zero during recovery before
calling tcp_rack_detect_loss(): when an ACK acknowledges all
packets marked lost before receiving this ACK, but has not yet
to discover new ones by tcp_rack_detect_loss(). The fix is to
simply test the congestion state directly.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ALR table operations are a sequence of related register operations which
should be protected from concurrent access. The alr_cache should also be
protected. Add alr_mutex doing that.
Signed-off-by: Egil Hjelmeland <privat@egil-hjelmeland.no>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since the block is freed with last chain being put, once we reach the
end of iteration of list_for_each_entry_safe, the block may be
already freed. I'm hitting this only by creating and deleting clsact:

[  202.171952] ==================================================================
[  202.180182] BUG: KASAN: use-after-free in tcf_block_put_ext+0x240/0x390
[  202.187590] Read of size 8 at addr ffff880225539a80 by task tc/796
[  202.194508]
[  202.196185] CPU: 0 PID: 796 Comm: tc Not tainted 4.15.0-rc2jiri+ #5
[  202.203200] Hardware name: Mellanox Technologies Ltd. "MSN2100-CB2F"/"SA001017", BIOS 5.6.5 06/07/2016
[  202.213613] Call Trace:
[  202.216369]  dump_stack+0xda/0x169
[  202.220192]  ? dma_virt_map_sg+0x147/0x147
[  202.224790]  ? show_regs_print_info+0x54/0x54
[  202.229691]  ? tcf_chain_destroy+0x1dc/0x250
[  202.234494]  print_address_description+0x83/0x3d0
[  202.239781]  ? tcf_block_put_ext+0x240/0x390
[  202.244575]  kasan_report+0x1ba/0x460
[  202.248707]  ? tcf_block_put_ext+0x240/0x390
[  202.253518]  tcf_block_put_ext+0x240/0x390
[  202.258117]  ? tcf_chain_flush+0x290/0x290
[  202.262708]  ? qdisc_hash_del+0x82/0x1a0
[  202.267111]  ? qdisc_hash_add+0x50/0x50
[  202.271411]  ? __lock_is_held+0x5f/0x1a0
[  202.275843]  clsact_destroy+0x3d/0x80 [sch_ingress]
[  202.281323]  qdisc_destroy+0xcb/0x240
[  202.285445]  qdisc_graft+0x216/0x7b0
[  202.289497]  tc_get_qdisc+0x260/0x560

Fix this by holding the block also by chain 0 and put chain 0
explicitly, out of the list_for_each_entry_safe loop at the very
end of tcf_block_put_ext.

Fixes: efbf7897 ("net_sched: get rid of rcu_barrier() in tcf_block_put_ext()")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

After applying 2270bc5d ("bnxt_en: Fix netpoll handling") and
903649e7 ("bnxt_en: Improve -ENOMEM logic in NAPI poll loop."),
we still see the following WARN fire:

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 1875170 at net/core/netpoll.c:165 netpoll_poll_dev+0x15a/0x160
  bnxt_poll+0x0/0xd0 exceeded budget in poll
  <snip>
  Call Trace:
   [<ffffffff814be5cd>] dump_stack+0x4d/0x70
   [<ffffffff8107e013>] __warn+0xd3/0xf0
   [<ffffffff8107e07f>] warn_slowpath_fmt+0x4f/0x60
   [<ffffffff8179519a>] netpoll_poll_dev+0x15a/0x160
   [<ffffffff81795f38>] netpoll_send_skb_on_dev+0x168/0x250
   [<ffffffff817962fc>] netpoll_send_udp+0x2dc/0x440
   [<ffffffff815fa9be>] write_ext_msg+0x20e/0x250
   [<ffffffff810c8125>] call_console_drivers.constprop.23+0xa5/0x110
   [<ffffffff810c9549>] console_unlock+0x339/0x5b0
   [<ffffffff810c9a88>] vprintk_emit+0x2c8/0x450
   [<ffffffff810c9d5f>] vprintk_default+0x1f/0x30
   [<ffffffff81173df5>] printk+0x48/0x50
   [<ffffffffa0197713>] edac_raw_mc_handle_error+0x563/0x5c0 [edac_core]
   [<ffffffffa0197b9b>] edac_mc_handle_error+0x42b/0x6e0 [edac_core]
   [<ffffffffa01c3a60>] sbridge_mce_output_error+0x410/0x10d0 [sb_edac]
   [<ffffffffa01c47cc>] sbridge_check_error+0xac/0x130 [sb_edac]
   [<ffffffffa0197f3c>] edac_mc_workq_function+0x3c/0x90 [edac_core]
   [<ffffffff81095f8b>] process_one_work+0x19b/0x480
   [<ffffffff810967ca>] worker_thread+0x6a/0x520
   [<ffffffff8109c7c4>] kthread+0xe4/0x100
   [<ffffffff81884c52>] ret_from_fork+0x22/0x40

This happens because we increment rx_pkts on -ENOMEM and -EIO, resulting
in rx_pkts > 0. Fix this by only bumping rx_pkts if we were actually
given a non-zero budget.
Signed-off-by: Calvin Owens <calvinowens@fb.com>
Acked-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

John Fastabend says:

====================
lockless qdisc series

This series adds support for building lockless qdiscs. This is
the result of noticing the qdisc lock is a common hot-spot in
perf analysis of the Linux network stack, especially when testing
with high packet per second rates. However, nothing is free and
most qdiscs rely on the qdisc lock for their data structures so
each qdisc must be converted on a case by case basis. In this
series, to kick things off, we make pfifo_fast, mq, and mqprio
lockless. Follow up series can address additional qdiscs as needed.
For example sch_tbf might be useful. To allow this the lockless
design is an opt-in flag. In some future utopia we convert all
qdiscs and we get to drop this case analysis, but in order to
make progress we live in the real-world.

There are also a handful of optimizations I have behind this
series and a few code cleanups that I couldn't figure out how
to fit neatly into this series with out increasing the patch
count. Once this is in additional patches can address this. The
most notable is in skb_dequeue we can push the consumer lock
out a bit and consume multiple skbs off the skb_array in pfifo
fast per iteration. Ideally we could push arrays of packets at
drivers as well but we would need the infrastructure for this.
The other notable improvement is to do less locking in the
overrun cases where bad tx queue list and gso_skb are being
hit. Although, nice in theory in practice this is the error
case and I haven't found a benchmark where this matters yet.

For testing...

My first test case uses multiple containers (via cilium) where
multiple client containers use 'wrk' to benchmark connections with
a server container running lighttpd. Where lighttpd is configured
to use multiple threads, one per core. Additionally this test has
a proxy agent running so all traffic takes an extra hop through a
proxy container. In these cases each TCP packet traverses the egress
qdisc layer at least four times and the ingress qdisc layer an
additional four times. This makes for a good stress test IMO, perf
details below.

The other micro-benchmark I run is injecting packets directly into
qdisc layer using pktgen. This uses the benchmark script,

 ./pktgen_bench_xmit_mode_queue_xmit.sh

Benchmarks taken in two cases, "base" running latest net-next no
changes to qdisc layer and "qdisc" tests run with qdisc lockless
updates. Numbers reported in req/sec. All virtual 'veth' devices
run with pfifo_fast in the qdisc test case.

`wrk -t16 -c $conns -d30 "http://[$SERVER_IP4]:80"`

conns    16      32     64   1024
-----------------------------------------------
base:   18831  20201  21393  29151
qdisc:  19309  21063  23899  29265

notice in all cases we see performance improvement when running
with qdisc case.

Microbenchmarks using pktgen are as follows,

`pktgen_bench_xmit_mode_queue_xmit.sh -t 1 -i eth2 -c 20000000

base(mq):          2.1Mpps
base(pfifo_fast):  2.1Mpps
qdisc(mq):         2.6Mpps
qdisc(pfifo_fast): 2.6Mpps

notice numbers are the same for mq and pfifo_fast because only
testing a single thread here. In both tests we see a nice bump
in performance gain. The key with 'mq' is it is already per
txq ring so contention is minimal in the above cases. Qdiscs
such as tbf or htb which have more contention will likely show
larger gains when/if lockless versions are implemented.

Thanks to everyone who helped with this work especially Daniel
Borkmann, Eric Dumazet and Willem de Bruijn for discussing the
design and reviewing versions of the code.

Changes from the RFC: dropped a couple patches off the end,
fixed a bug with skb_queue_walk_safe not unlinking skb in all
cases, fixed a lockdep splat with pfifo_fast_destroy not calling
*_bh lock variant, addressed _most_ of Willem's comments, there
was a bug in the bulk locking (final patch) of the RFC series.

@Willem, I left out lockdep annotation for a follow on series
to add lockdep more completely, rather than just in code I
touched.

Comments and feedback welcome.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This converts the pfifo_fast qdisc to use the skb_array data structure
and set the lockless qdisc bit. pfifo_fast is the first qdisc to support
the lockless bit that can be a child of a qdisc requiring locking. So
we add logic to clear the lock bit on initialization in these cases when
the qdisc graft operation occurs.

This also removes the logic used to pick the next band to dequeue from
and instead just checks a per priority array for packets from top priority
to lowest. This might need to be a bit more clever but seems to work
for now.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This adds a peek routine to skb_array.h for use with qdisc.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The sch_mqprio qdisc creates a sub-qdisc per tx queue which are then
called independently for enqueue and dequeue operations. However
statistics are aggregated and pushed up to the "master" qdisc.

This patch adds support for any of the sub-qdiscs to be per cpu
statistic qdiscs. To handle this case add a check when calculating
stats and aggregate the per cpu stats if needed.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>