The commit 8f6fd83c ("rhashtable:
accept GFP flags in rhashtable_walk_init") added a GFP flag argument
to rhashtable_walk_init because some users wish to use the walker
in an unsleepable context.

In fact we don't need to allocate memory in rhashtable_walk_init
at all.  The walker is always paired with an iterator so we could
just stash ourselves there.

This patch does that by introducing a new enter function to replace
the existing init function.  This way we don't have to churn all
the existing users again.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Hariprasad Shenai says:

====================
crypto/chcr: Add support for Chelsio Crypto Driver

This patch series adds support for Chelsio Crypto driver.

The patch series has been created against net-next tree and includes
patches for Chelsio Low Level Driver(cxgb4) and adds the new crypto
Upper Layer Driver(chcr) under a new directory drivers/crypto/chelsio.

Patch 1/4 ("cxgb4: Add support for dynamic allocation of resources for
ULD") adds support for dynamic allocation of resources for ULD. The
objective of this patch is to provide generic interface for upper layer
drivers to allocate and initialize hardware resources.

The present cxgb4 (network driver) apart from network functionality, also
initializes hardware and thus acts as lower layer driver for other drivers
to use hardware resources. Thus it acts as both a Low level driver for
Upper layer driver's like iw_cxgb4, cxgb4i and cxgb4it and a Network Driver.

Right now the allocation of resources for Upper layer driver's is done
statically. Patch 1/4 adds a new infrastructure for dynamic allocation of
resources. cxgb4 will read the hardware capability through firmware and
allocate/free the queues for Upper layer drivers when the respective
driver's are loaded and freed when unloaded.

Patch 2/3, 3/4 and 4/4 adds support for Chelsio Crypto Driver. The Crypto
driver will act as another ULD on top of cxgb4.

In this patch series, the ULD API framework is used only by crypto and other
ULD's will make use of it in the next series.

This patch series is only for review, if this looks ok we will test it
thoroughly and send request for merge.

We have included all the maintainers of respective drivers. Kindly
review the changes and provide feedback on the same.

V3: - Removed crypto queues from cxgb4 and added support for dynamic
      allocation of resources for Upper layer drivers
    - Dependency fix in Kconfig.

V2: - Some residual code cleanup
    - Adds pr_fmt with chcr (KBUILD_MODNAME) added
    - Changes var name to accomodate them <80 columns in the chcr_register_alg
    - Support for printing the crypto queue stats
    - Fix compile warnings reported by kbuild bot for certain architectures
    - Dependency fix in Kconfig.
    - If the request has the MAY_BACKLOG bit set and hardware queue is
      full the request is queued up else -EBUSY is returned to throttle
      the user. The queue when executed and processed returns -EINPROGRESS
      in completion.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Adds the config entry for the Chelsio Crypto Driver, Makefile changes
for the same.
Signed-off-by: NAtul Gupta <atul.gupta@chelsio.com>
Signed-off-by: NHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The Chelsio's Crypto Hardware can perform the following operations:
SHA1, SHA224, SHA256, SHA384 and SHA512, HMAC(SHA1), HMAC(SHA224),
HMAC(SHA256), HMAC(SHA384), HAMC(SHA512), AES-128-CBC, AES-192-CBC,
AES-256-CBC, AES-128-XTS, AES-256-XTS

This patch implements the driver for above mentioned features. This
driver is an Upper Layer Driver which is attached to Chelsio's LLD
(cxgb4) and uses the queue allocated by the LLD for sending the crypto
requests to the Hardware and receiving the responses from it.

The crypto operations can be performed by Chelsio's hardware from the
userspace applications and/or from within the kernel space using the
kernel's crypto API.

The above mentioned crypto features have been tested using kernel's
tests mentioned in testmgr.h. They also have been tested from user
space using libkcapi and Openssl.
Signed-off-by: NAtul Gupta <atul.gupta@chelsio.com>
Signed-off-by: NHariprasad Shenai <hariprasad@chelsio.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAtul Gupta <atul.gupta@chelsio.com>
Signed-off-by: NHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a new commmon infrastructure to allocate reosurces dynamically to
Upper layer driver's(ULD) when they register with cxgb4 driver and free
them during unregistering. All the queues and the interrupts for
them will be allocated during ULD probe only and freed during remove.
Signed-off-by: NAtul Gupta <atul.gupta@chelsio.com>
Signed-off-by: NHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The data member of structure firmware is const and this constness is
dropped by some cast.
This patch add some const for keeping the const information.
Signed-off-by: NLABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Daniel Borkmann says:

====================
BPF helper improvements and cleanups

This set adds various improvements to BPF helpers, a cleanup to use
skb_pkt_type_ok() helper, addition of bpf_skb_change_tail(), a follow
up for event output helper and removing ifdefs around the cgroupv2
helper bits. For details please see individual patches.

The set is based against net-next tree, but requires a merge of net
into net-next first.

Thanks a lot!
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As recently discussed during the task_under_cgroup_hierarchy() addition,
we should get rid of the ifdefs surrounding the bpf_skb_under_cgroup()
helper. If related functionality is not built-in, the helper cannot be
used anyway, which is also in line with what we do for all other helpers.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Follow-up to 555c8a86 ("bpf: avoid stack copy and use skb ctx for
event output") for also adding the event output helper for XDP typed
programs. The event output helper has been very useful in particular for
debugging or event notification purposes, since it's much faster and
flexible than regular trace printk due to programmatically being able to
attach meta data. Same flags structure applies as with tc BPF programs.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This work adds a bpf_skb_change_tail() helper for tc BPF programs. The
basic idea is to expand or shrink the skb in a controlled manner. The
eBPF program can then rewrite the rest via helpers like bpf_skb_store_bytes(),
bpf_lX_csum_replace() and others rather than passing a raw buffer for
writing here.

bpf_skb_change_tail() is really a slow path helper and intended for
replies with f.e. ICMP control messages. Concept is similar to other
helpers like bpf_skb_change_proto() helper to keep the helper without
protocol specifics and let the BPF program mangle the remaining parts.
A flags field has been added and is reserved for now should we extend
the helper in future.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since we have a skb_pkt_type_ok() helper for checking the type before
mangling, make use of it instead of open coding. Follow-up to commit
8b10cab6 ("net: simplify and make pkt_type_ok() available for other
users") that came in after d2485c42 ("bpf: add bpf_skb_change_type
helper").
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add TIPC_NL_PEER_REMOVE netlink command. This command can remove
an offline peer node from the internal data structures.

This will be supported by the tipc user space tool in iproute2.
Signed-off-by: NRichard Alpe <richard.alpe@ericsson.com>
Reviewed-by: NJon Maloy <jon.maloy@ericsson.com>
Acked-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Over the years, TCP BDP has increased a lot, and is typically
in the order of ~10 Mbytes with help of clever Congestion Control
modules.

In presence of packet losses, TCP stores incoming packets into an out of
order queue, and number of skbs sitting there waiting for the missing
packets to be received can match the BDP (~10 Mbytes)

In some cases, TCP needs to make room for incoming skbs, and current
strategy can simply remove all skbs in the out of order queue as a last
resort, incurring a huge penalty, both for receiver and sender.

Unfortunately these 'last resort events' are quite frequent, forcing
sender to send all packets again, stalling the flow and wasting a lot of
resources.

This patch cleans only a part of the out of order queue in order
to meet the memory constraints.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: C. Stephen Gun <csg@google.com>
Cc: Van Jacobson <vanj@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: NYuchung Cheng <ycheng@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It doesn't really change anything as BGMAC_CHIPCTL_1_IF_TYPE_RMII is
equal to 0. It make code a bit clener, so far when reading it one could
think we forgot to set a proper mode. It also keeps this mode code in
sync with other ones.
Signed-off-by: NRafał Miłecki <rafal@milecki.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

BCM53573 is a new series of Broadcom's SoCs. It's based on ARM and can
be found in two packages (versions): BCM53573 and BCM47189. It shares
some code with the Northstar family, but also requires some new quirks.

First of all there can be up to 2 Ethernet cores on this SoC. If that is
the case, they are connected to two different switch ports allowing some
more complex/optimized setups. It seems the second unit doesn't come
fully configured and requires some IRQ quirk.

Other than that only the first core is connected to the PHY. For the
second one we have to register fixed PHY (similarly to the Northstar),
otherwise generic PHY driver would get some invalid info.

This has been successfully tested on Tenda AC9 (BCM47189B0).
Signed-off-by: NRafał Miłecki <rafal@milecki.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

trivial fix to spelling mistake in dev_err message
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is useful to be able to see the hash configuration when running tests.
This patch adds a debugfs node for that purpose.
Signed-off-by: NPaul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The division is already being done properly in efx_ef10_get_timer_config
which returns zero-on-success, unlike the old efx_ef10_get_sysclk_freq.

Fixes: d95e329a ("sfc: get timer configuration from adapter")
Signed-off-by: NEdward Cree <ecree@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While chasing tcp_xmit_retransmit_queue() kasan issue, I found
that we could avoid reading sacked field of skb that we wont send,
possibly removing one cache line miss.

Very minor change in slow path, but why not ? ;)
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Nikolay Aleksandrov says:

====================
net: bridge: export vlan stats per-port with flags

This set adds the ability to export vlan stats per-port. Patch 01 makes
that possible by consolidating the bridge and port linkxstats calls. Then
patch 02 allows to dump the vlan entry flags in order to be able to
distinguish between bridge and port vlan entries when dumping the master
device vlan stats. That is needed because that call was implemented when
the stats API didn't have slave dumping capabilities and it dumps all vlan
stats (for both bridge and port entries). We also need it in order to print
the vlan flags when dumping the stats.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use one of the vlan xstats padding fields to export the vlan flags. This is
needed in order to be able to distinguish between master (bridge) and port
vlan entries in user-space when dumping the bridge vlan stats.
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the bridge driver we usually have the same function working for both
port and bridge. In order to follow that logic and also avoid code
duplication, consolidate the bridge_ and brport_ linkxstats calls into
one since they share most of their code. As a side effect this allows us
to dump the vlan stats also via the slave call which is in preparation for
the upcoming per-port vlan stats and vlan flag dumping.
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Hadar Hen Zion says:

====================
net_sched, flow_dissector, flower: Introduce vlan tag support

This patchset introduce vlan tag support to the flower classifier and the flow
dissector. In addition to adding vlan priority to act vlan.

The first 2 patches are dealing with flow-dissector:
 - The first patch is a fix, in case the vlan was already stripped from the
   skb, take it from skb->vlan_tci.
 - The second patch adds support for vlan priority.

The next 2 patches are dealing with flower:
 - The first patch is a fix, sets flow dissector 'used_keys' according to the
   mask value of each key.
 - The secound patch adds vlan tag support to the flower classifier, user space
   patches will be sent later to complete it.

The last patch adds vlan priority to act vlan since only vlan id is currently supported.

Changes from V1:
 - A new patch was added to this series "net_sched: flower: Avoid dissection of unmasked keys"
 - Adding u16 padding to struct flow_dissector_key_vlan
 - change flow_label field in struct flow_dissector_key_tags form 20 bits field to u32
 - Remove 'if (v->tcfv_push_prio)' check from tcf_vlan_dump function
 - Add support to un-stripped vlan skb and skb with multipale vlans in __skb_flow_dissect
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current vlan push action supports only vid and protocol options.
Add priority option.

Example script that adds vlan push action with vid and
priority:

tc filter add dev veth0 protocol ip parent ffff: \
	   flower \
	   	indev veth0 \
	   action vlan push id 100 priority 5
Signed-off-by: NHadar Hen Zion <hadarh@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Enhance flower to support 802.1Q vlan protocol classification.
Currently, the supported fields are vlan_id and vlan_priority.

Example:

	# add a flower filter with vlan id and priority classification
	tc filter add dev ens4f0 protocol 802.1Q parent ffff: \
		flower \
		indev ens4f0 \
		vlan_ethtype ipv4 \
		vlan_id 100 \
		vlan_prio 3 \
	action vlan pop
Signed-off-by: NHadar Hen Zion <hadarh@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current flower implementation checks the mask range and set all the
keys included in that range as "used_keys", even if a specific key in
the range has a zero mask.

This behavior can cause a false positive return value of
dissector_uses_key function and unnecessary dissection in
__skb_flow_dissect.

This patch checks explicitly the mask of each key and "used_keys" will
be set accordingly.

Fixes: 77b9900e ('tc: introduce Flower classifier')
Signed-off-by: NHadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add vlan priority check to the flow dissector by adding new flow
dissector struct, flow_dissector_key_vlan which includes vlan tag
fields.

vlan_id and flow_label fields were under the same struct
(flow_dissector_key_tags). It was a convenient setting since struct
flow_dissector_key_tags is used by struct flow_keys and by setting
vlan_id and flow_label under the same struct, we get precisely 24 or 48
bytes in flow_keys from flow_dissector_key_basic.

Now, when adding vlan priority support, the code will be cleaner if
flow_label and vlan tag won't be under the same struct anymore.
Signed-off-by: NHadar Hen Zion <hadarh@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Early in the datapath skb_vlan_untag function is called, stripped
the vlan from the skb and set skb->vlan_tci and skb->vlan_proto fields.

The current dissection doesn't handle stripped vlan packets correctly.
In some flows, vlan doesn't exist in skb->data anymore when applying
flow dissection on the skb, fix that.

In case vlan info wasn't stripped before applying flow_dissector (RPS
flow for example), or in case of skb with multiple vlans (e.g. 802.1ad),
get the vlan info from skb->data. The flow_dissector correctly skips
any number of vlans and stores only the first level vlan.

Fixes: 0744dd00 ('net: introduce skb_flow_dissect()')
Signed-off-by: NHadar Hen Zion <hadarh@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Yuval Mintz says:

====================
qed*: Fix ethtool issues relating to link

This series addresses two issues that were introduced when adding
support for ethtool's link_ksettings support - the first fixes a
regression and second incorrect functionallity in the submission.

Although these are fixes, as the feature currently exists only in
'next-next' I'm aiming them for it.

Dave, please consider applying this series to 'net-next'.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While '0xdead' and '0xbeef' are "great" values, we should
use the correct SPEED_* values instead.

Fixes: 054c67d1 ("qed*: Add support for ethtool link_ksettings callbacks")
Signed-off-by: NYuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When moving into using ethtool's link_ksetting, qed started
supplying its own bitmask of speed/capabilities, but qede
is still checking for the SUPPORTED value to determine whether
it supports pause.

Fixes: 054c67d1 ("qed*: Add support for ethtool link_ksettings callbacks")
Signed-off-by: NYuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Jeff Kirsher says:

====================
1GbE Intel Wired LAN Driver Updates 2016-08-18

This series contains updates to igb only.

Gangfeng Huang provides all the changes in the series to update the
igb driver to support advanced receive side filters that direct receive
packets by flows to different hardware queues. This enables a tight
control on routing a flow in the platform.  First patch allows for
receive network flow classification to insert and remove receive filters
by ethtool.  Second and third patches add the ability to insert and
remove ethertype and VLAN priority filters by ethtool.

Last patch just fixes an error message to return "Not supported" versus
"Unknown error 524".
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use error "rmgr: Cannot insert RX class rule: Operation not supported" is
more meaningful than "rmgr: Cannot insert RX class rule: Unknown error 524"
Signed-off-by: NGangfeng Huang <gangfeng.huang@ni.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

This patch is meant to allow for RX network flow classification to insert
and remove VLAN priority filter by ethtool

Example:
Add an VLAN priority filter:
$ ethtool -N eth0 flow-type ether vlan 0x6000 vlan-mask 0x1FFF action 2 loc 1

Show all filters:
$ ethtool -n eth0
4 RX rings available
Total 1 rules

Filter: 1
	Flow Type: Raw Ethernet
	Src MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
	Dest MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
	Ethertype: 0x0 mask: 0xFFFF
	VLAN EtherType: 0x0 mask: 0xffff
	VLAN: 0x6000 mask: 0x1fff
	User-defined: 0x0 mask: 0xffffffffffffffff
	Action: Direct to queue 2

Delete the filter by location:
$ ethtool -N delete 1
Signed-off-by: NRuhao Gao <ruhao.gao@ni.com>
Signed-off-by: NGangfeng Huang <gangfeng.huang@ni.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

This patch is meant to allow for RX network flow classification to insert
and remove ethertype filter by ethtool

Example:
Add an ethertype filter:
$ ethtool -N eth0 flow-type ether proto 0x88F8 action 2

Show all filters:
$ ethtool -n eth0
4 RX rings available
Total 1 rules

Filter: 15
	Flow Type: Raw Ethernet
	Src MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
	Dest MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
	Ethertype: 0x88F8 mask: 0x0
	Action: Direct to queue 2

Delete the filter by location:
$ ethtool -N delete 15
Signed-off-by: NRuhao Gao <ruhao.gao@ni.com>
Signed-off-by: NGangfeng Huang <gangfeng.huang@ni.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

This patch is meant to allow for RX network flow classification to insert
and remove Rx filter by ethtool. Ethtool interface has it's own rules
manager

Show all filters:
$ ethtool -n eth0
4 RX rings available
Total 2 rules
Signed-off-by: NRuhao Gao <ruhao.gao@ni.com>
Signed-off-by: NGangfeng Huang <gangfeng.huang@ni.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

Jiri Kosina says:

====================
qdisc-hashtable fixes

The following two patches fix all the issues that have been reported
against the conversion of qdisc linked list to hashtable (currently in
net-next) so far.

First patch adjusts handling of singleton qdiscs to the new semantics, and
is rather straightforward.

The second patch, which fixes "cosmetic" issue of duplicate entries in the
qdisc dump for ingress qdiscs, is a little bit more hairy; I personally
would love to see all the already existing "if (ingress)"-like hacks go
away (by, let's say, introducing a general TCQ_F_? flag), but that's way
out of scope of this patchset (but already on my todo).

Thanks a lot to Daniel Borkmann and David Ahern for reporting the issues
and testing the patches promptly.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tc_dump_qdisc() performs dumping of the per-device qdiscs in two phases;
first, the "standard" dev->qdisc is being dumped. Second, if there is/are
ingress queue(s), they are being dumped as well.

After conversion of netdevice's qdisc linked-list into hashtable, these
two sets are not in two disjunctive sets/lists any more, but are both
"reachable" directly from netdevice's hashtable. As a consequence, the
"full-depth" dump of the ingress qdiscs results in immediately hitting the
netdevice hashtable again, and duplicating the dump that has already been
performed for dev->qdisc.
What in fact needs to be dumped in case of ingress queue is "just" the
top-level ingress qdisc, as everything else has been dumped already.

Fix this by extending tc_dump_qdisc_root() in a way that it can be instructed
whether it should (while performing the "full" per-netdev qdisc dump) perform
the whole recursion, or just dump "additional" top-level (ingress) qdiscs
without performing any kind of recursion.

This fixes duplicate dumps such as

	qdisc mq 0: root
	qdisc pfifo_fast 0: parent :4 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
	qdisc pfifo_fast 0: parent :3 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
	qdisc pfifo_fast 0: parent :2 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
	qdisc pfifo_fast 0: parent :1 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
	qdisc clsact ffff: parent ffff:fff1
	qdisc pfifo_fast 0: parent :4 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
	qdisc pfifo_fast 0: parent :3 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
	qdisc pfifo_fast 0: parent :2 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
	qdisc pfifo_fast 0: parent :1 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1

Fixes: 59cc1f61 ("net: sched: convert qdisc linked list to hashtable")
Reported-by: NDaniel Borkmann <daniel@iogearbox.net>
Tested-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

qdisc_match_from_root() is now iterating over per-netdevice qdisc
hashtable instead of going through a linked-list of qdiscs (independently
on the actual underlying netdev), which was the case before the switch to
hashtable for qdiscs.

For singleton qdiscs, there is no underlying netdev associated though, and
therefore dumping a singleton qdisc will panic, as qdisc_dev(root) will
always be NULL.

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000410
 IP: [<ffffffff8167efac>] qdisc_match_from_root+0x2c/0x70
 PGD 1aceba067 PUD 1aceb7067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP
[ ... ]
 task: ffff8801ec996e00 task.stack: ffff8801ec934000
 RIP: 0010:[<ffffffff8167efac>]  [<ffffffff8167efac>] qdisc_match_from_root+0x2c/0x70
 RSP: 0018:ffff8801ec937ab0  EFLAGS: 00010203
 RAX: 0000000000000408 RBX: ffff88025e612000 RCX: ffffffffffffffd8
 RDX: 0000000000000000 RSI: 00000000ffff0000 RDI: ffffffff81cf8100
 RBP: ffff8801ec937ab0 R08: 000000000001c160 R09: ffff8802668032c0
 R10: ffffffff81cf8100 R11: 0000000000000030 R12: 00000000ffff0000
 R13: ffff88025e612000 R14: ffffffff81cf3140 R15: 0000000000000000
 FS:  00007f24b9af6740(0000) GS:ffff88026f280000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000410 CR3: 00000001aceec000 CR4: 00000000001406e0
 Stack:
  ffff8801ec937ad0 ffffffff81681210 ffff88025dd51a00 00000000fffffff1
  ffff8801ec937b88 ffffffff81681e4e ffffffff81c42bc0 ffff880262431500
  ffffffff81cf3140 ffff88025dd51a10 ffff88025dd51a24 00000000ec937b38
 Call Trace:
  [<ffffffff81681210>] qdisc_lookup+0x40/0x50
  [<ffffffff81681e4e>] tc_modify_qdisc+0x21e/0x550
  [<ffffffff8166ae25>] rtnetlink_rcv_msg+0x95/0x220
  [<ffffffff81209602>] ? __kmalloc_track_caller+0x172/0x230
  [<ffffffff8166ad90>] ? rtnl_newlink+0x870/0x870
  [<ffffffff816897b7>] netlink_rcv_skb+0xa7/0xc0
  [<ffffffff816657c8>] rtnetlink_rcv+0x28/0x30
  [<ffffffff8168919b>] netlink_unicast+0x15b/0x210
  [<ffffffff81689569>] netlink_sendmsg+0x319/0x390
  [<ffffffff816379f8>] sock_sendmsg+0x38/0x50
  [<ffffffff81638296>] ___sys_sendmsg+0x256/0x260
  [<ffffffff811b1275>] ? __pagevec_lru_add_fn+0x135/0x280
  [<ffffffff811b1a90>] ? pagevec_lru_move_fn+0xd0/0xf0
  [<ffffffff811b1140>] ? trace_event_raw_event_mm_lru_insertion+0x180/0x180
  [<ffffffff811b1b85>] ? __lru_cache_add+0x75/0xb0
  [<ffffffff817708a6>] ? _raw_spin_unlock+0x16/0x40
  [<ffffffff811d8dff>] ? handle_mm_fault+0x39f/0x1160
  [<ffffffff81638b15>] __sys_sendmsg+0x45/0x80
  [<ffffffff81638b62>] SyS_sendmsg+0x12/0x20
  [<ffffffff810038e7>] do_syscall_64+0x57/0xb0

Fix this by special-casing singleton qdiscs (those that don't have
underlying netdevice) and introduce immediate handling of those rather
than trying to go over an underlying netdevice. We're in the same
situation in tc_dump_qdisc_root() and tc_dump_tclass_root().

Ultimately, this will have to be slightly reworked so that we are actually
able to show singleton qdiscs (noop) in the dump properly; but we're not
currently doing that anyway, so no regression there, and better do this in
a gradual manner.

Fixes: 59cc1f61 ("net: sched: convert qdisc linked list to hashtable")
Reported-by: NDaniel Borkmann <daniel@iogearbox.net>
Tested-by: NDaniel Borkmann <daniel@iogearbox.net>
Reported-by: NDavid Ahern <dsa@cumulusnetworks.com>
Tested-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>