Call skb_get_hash_perturb instead of doing skb_flow_dissect and then
jhash by hand.
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Call skb_get_hash_perturb instead of doing skb_flow_dissect and then
jhash by hand.
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Call skb_get_hash_perturb instead of doing skb_flow_dissect and then
jhash by hand.
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Call skb_get_hash_perturb instead of doing skb_flow_dissect and then
jhash by hand.
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This calls flow_disect and __skb_get_hash to procure a hash for a
packet. Input includes a key to initialize jhash. This function
does not set skb->hash.
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In setups with a global scope address on an interface, and a lesser
scope address on an interface sending IGMP reports, the reports can be
sent using the other interfaces global scope address rather than the
local interface address. RFC 2236 suggests:

     Ignore the Report if you cannot identify the source address of
     the packet as belonging to a subnet assigned to the interface on
     which the packet was received.

since such reports could be forged.

Look at the protocol when deciding if a RT_SCOPE_LINK address should
be used for the packet.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TC classifiers/actions were converted to RCU by John in the series:
http://thread.gmane.org/gmane.linux.network/329739/focus=329739
and many follow on patches.
This is the last patch from that series that finally drops
ingress spin_lock.

Single cpu ingress+u32 performance goes from 22.9 Mpps to 24.5 Mpps.

In two cpu case when both cores are receiving traffic on the same
device and go into the same ingress+u32 the performance jumps
from 4.5 + 4.5 Mpps to 23.5 + 23.5 Mpps
Signed-off-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Invoking pkts_acked is currently conditioned on FLAG_ACKED:
receiving a cumulative ACK of new data, or ACK with SYN flag set.

Remove this condition so that CC may get RTT measurements from all SACKs.

Cc: Yuchung Cheng <ycheng@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: NKenneth Klette Jonassen <kennetkl@ifi.uio.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_sacktag_one() always picks the earliest sequence SACKed for RTT.
This might not make sense for congestion control in cases where:

  1. ACKs are lost, i.e. a SACK following a lost SACK covers both
     new and old segments at the receiver.
  2. The receiver disregards the RFC 5681 recommendation to immediately
     ACK out-of-order segments.

Give congestion control a RTT for the latest segment SACKed, which is the
most accurate RTT estimate, but preserve the conservative RTT for RTO.

Removes the call to skb_mstamp_get() in tcp_sacktag_one().

Cc: Yuchung Cheng <ycheng@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: NKenneth Klette Jonassen <kennetkl@ifi.uio.no>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Later patch passes two values set in tcp_sacktag_one() to
tcp_clean_rtx_queue(). Prepare passing them via struct tcp_sacktag_state.
Acked-by: NYuchung Cheng <ycheng@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: NKenneth Klette Jonassen <kennetkl@ifi.uio.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid recomputing the Ethernet header location and instead just use the
pointer provided by skb->data.  The problem with using eth_hdr is that the
compiler wasn't smart enough to realize that skb->head + skb->mac_header
was the same thing as skb->data before it added ETH_HLEN.  By just caching
it off before calling skb_pull_inline we can avoid a few unnecessary
instructions.
Signed-off-by: NAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change makes it so that we process the address in
is_multicast_ether_addr at the same size as the other calls.  This allows
us to avoid duplicate reads when used with other calls such as
is_zero_ether_addr or eth_addr_copy.  In addition I have added a 64 bit
version of the function so in eth_type_trans we can process the destination
address as a 64 bit value throughout.
Signed-off-by: NAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change takes advantage of the fact that ETH_P_802_3_MIN is aligned to
512 so as a result we can actually ignore the lower 8b when comparing the
Ethertype to ETH_P_802_3_MIN.  This allows us to avoid a byte swap by simply
masking the value and comparing it to the byte swapped value for
ETH_P_802_3_MIN.
Signed-off-by: NAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch divides the IPv6 flow label space into two ranges:
0-7ffff is reserved for flow label manager, 80000-fffff will be
used for creating auto flow labels (per RFC6438). This only affects how
labels are set on transmit, it does not affect receive. This range split
can be disbaled by systcl.

Background:

IPv6 flow labels have been an unmitigated disappointment thus far
in the lifetime of IPv6. Support in HW devices to use them for ECMP
is lacking, and OSes don't turn them on by default. If we had these
we could get much better hashing in IPv6 networks without resorting
to DPI, possibly eliminating some of the motivations to to define new
encaps in UDP just for getting ECMP.

Unfortunately, the initial specfications of IPv6 did not clarify
how they are to be used. There has always been a vague concept that
these can be used for ECMP, flow hashing, etc. and we do now have a
good standard how to this in RFC6438. The problem is that flow labels
can be either stateful or stateless (as in RFC6438), and we are
presented with the possibility that a stateless label may collide
with a stateful one.  Attempts to split the flow label space were
rejected in IETF. When we added support in Linux for RFC6438, we
could not turn on flow labels by default due to this conflict.

This patch splits the flow label space and should give us
a path to enabling auto flow labels by default for all IPv6 packets.
This is an API change so we need to consider compatibility with
existing deployment. The stateful range is chosen to be the lower
values in hopes that most uses would have chosen small numbers.

Once we resolve the stateless/stateful issue, we can proceed to
look at enabling RFC6438 flow labels by default (starting with
scaled testing).
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In my earlier commit:
653437d0 ("ipv6: Stop /128 route from disappearing after pmtu update"),
there was a horrible typo.  Instead of checking RTF_LOCAL on
rt->rt6i_flags, it was checked on rt->dst.flags.  This patch fixes
it.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Cc: Hajime Tazaki <tazaki@sfc.wide.ad.jp>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Not used.

pedit sets TC_MUNGED when packet content was altered, but all the core
does is unset MUNGED again and then set OK2MUNGE.

And the latter isn't tested anywhere. So lets remove both
TC_MUNGED and TC_OK2MUNGE.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The whole hlist will be moved, so not need to call hlist_del before
add the hlist_node to other hlist_head.
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If we don't do that, then the poison value is left in the ->pprev
backlink.

This can cause crashes if we do a disconnect, followed by a connect().
Tested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reported-by: NWen Xu <hotdog3645@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

_rt6i_peer is no longer needed after the last patch,
'ipv6: Stop rt6_info from using inet_peer's metrics'.

DST_METRICS_FORCE_OVERWRITE is added by
commit e5fd387a ("ipv6: do not overwrite inetpeer metrics prematurely").
Since inetpeer is no longer used for metrics, this bit is also not needed.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Reviewed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Michal Kubeček <mkubecek@suse.cz>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

inet_peer is indexed by the dst address alone.  However, the fib6 tree
could have multiple routing entries (rt6_info) for the same dst. For
example,
1. A /128 dst via multiple gateways.
2. A RTF_CACHE route cloned from a /128 route.

In the above cases, all of them will share the same metrics and
step on each other.

This patch will steer away from inet_peer's metrics and use
dst_cow_metrics_generic() for everything.

Change Highlights:
1. Remove rt6_cow_metrics() which currently acquires metrics from
   inet_peer for DST_HOST route (i.e. /128 route).
2. Add rt6i_pmtu to take care of the pmtu update to avoid creating a
   full size metrics just to override the RTAX_MTU.
3. After (2), the RTF_CACHE route can also share the metrics with its
   dst.from route, by:
   dst_init_metrics(&cache_rt->dst, dst_metrics_ptr(cache_rt->dst.from), true);
4. Stop creating RTF_CACHE route by cloning another RTF_CACHE route.  Instead,
   directly clone from rt->dst.

   [ Currently, cloning from another RTF_CACHE is only possible during
     rt6_do_redirect().  Also, the old clone is removed from the tree
     immediately after the new clone is added. ]

   In case of cloning from an older redirect RTF_CACHE, it should work as
   before.

   In case of cloning from an older pmtu RTF_CACHE, this patch will forget
   the pmtu and re-learn it (if there is any) from the redirected route.

The _rt6i_peer and DST_METRICS_FORCE_OVERWRITE will be removed
in the next cleanup patch.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Reviewed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is mostly from Steffen Klassert <steffen.klassert@secunet.com>.
I only removed the (rt6->rt6i_dst.plen == 128) check from
ip6_rt_update_pmtu() because the (rt6->rt6i_flags & RTF_CACHE) test
has already implied it.

This patch:
1. Create RTF_CACHE route for /128 non local route
2. After (1), all routes that allow pmtu update should have a RTF_CACHE
   clone.  Hence, stop updating MTU for any non RTF_CACHE route.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We search only for routes with highest priority metric in
find_rr_leaf(). However if one of these routes is marked
as invalid, we may fail to find a route even if there is
a appropriate route with lower priority. Then we loose
connectivity until the garbage collector deletes the
invalid route. This typically happens if a host route
expires afer a pmtu event. Fix this by searching also
for routes with a lower priority metric.
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Reviewed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is a prep work for the later bug-fix patch which will stop /128 route
from disappearing after pmtu update.

The later bug-fix patch will allow a /128 route and its RTF_CACHE clone
both exist at the same fib6_node.  To do this, we need to prepare the
existing fib6 tree search to expect RTF_CACHE for /128 route.

Note that the fn->leaf is sorted by rt6i_metric.  Hence,
RTF_CACHE (if there is any) is always at the front.  This property
leads to the following:

1. When doing ip6_route_del(), it should honor the RTF_CACHE flag which
   the caller is used to ask for deleting clone or non-clone.
   The rtm_to_fib6_config() should also check the RTM_F_CLONED and
   then set RTF_CACHE accordingly so that:
   - 'ip -6 r del...' will make ip6_route_del() to delete a route
     and all its clones. Note that its clones is flushed by fib6_del()
   - 'ip -6 r flush table cache' will make ip6_route_del() to
      only delete clone(s).

2. Exclude RTF_CACHE from addrconf_get_prefix_route() which
   should not configure on a cloned route.

3. No change is need for rt6_device_match() since it currently could
   return a RTF_CACHE clone route, so the later bug-fix patch will not
   affect it.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Reviewed-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Under stress, ip_idents_reserve() is accessing a contended
cache line twice, with non optimal MESI transactions.

If we place timestamps in separate location, we reduce this
pressure by ~50% and allow atomic_add_return() to issue
a Request for Ownership.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I forgot to update tcp_westwood when changing get_info() behavior,
this patch should fix this.

Fixes: 64f40ff5 ("tcp: prepare CC get_info() access from getsockopt()")
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_mark_lost_retrans is not used when FACK is disabled. Since
tcp_update_reordering may disable FACK, it should be called first
before tcp_mark_lost_retrans.
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNandita Dukkipati <nanditad@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some Congestion Control modules can provide per flow information,
but current way to get this information is to use netlink.

Like TCP_INFO, let's add TCP_CC_INFO so that applications can
issue a getsockopt() if they have a socket file descriptor,
instead of playing complex netlink games.

Sample usage would be :

  union tcp_cc_info info;
  socklen_t len = sizeof(info);

  if (getsockopt(fd, SOL_TCP, TCP_CC_INFO, &info, &len) == -1)
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We would like that optional info provided by Congestion Control
modules using netlink can also be read using getsockopt()

This patch changes get_info() to put this information in a buffer,
instead of skb, like tcp_get_info(), so that following patch
can reuse this common infrastructure.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch tracks total number of payload bytes received on a TCP socket.
This is the sum of all changes done to tp->rcv_nxt

RFC4898 named this : tcpEStatsAppHCThruOctetsReceived

This is a 64bit field, and can be fetched both from TCP_INFO
getsockopt() if one has a handle on a TCP socket, or from inet_diag
netlink facility (iproute2/ss patch will follow)

Note that tp->bytes_received was placed near tp->rcv_nxt for
best data locality and minimal performance impact.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Matt Mathis <mattmathis@google.com>
Cc: Eric Salo <salo@google.com>
Cc: Martin Lau <kafai@fb.com>
Cc: Chris Rapier <rapier@psc.edu>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch tracks total number of bytes acked for a TCP socket.
This is the sum of all changes done to tp->snd_una, and allows
for precise tracking of delivered data.

RFC4898 named this : tcpEStatsAppHCThruOctetsAcked

This is a 64bit field, and can be fetched both from TCP_INFO
getsockopt() if one has a handle on a TCP socket, or from inet_diag
netlink facility (iproute2/ss patch will follow)

Note that tp->bytes_acked was placed near tp->snd_una for
best data locality and minimal performance impact.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NYuchung Cheng <ycheng@google.com>
Cc: Matt Mathis <mattmathis@google.com>
Cc: Eric Salo <salo@google.com>
Cc: Martin Lau <kafai@fb.com>
Cc: Chris Rapier <rapier@psc.edu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

eeprom-length is a switch property, not a dsa property, and thus
needs to be attached to the switch node, not to the dsa node.
Reported-by: NAndrew Lunn <andrew@lunn.ch>
Fixes: 6793abb4 ("net: dsa: Add support for switch EEPROM access")
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Acked-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, we try to accumulate arrived packets in the links's
'deferred' queue during the parallel link syncronization phase.

This entails two problems:

- With an unlucky combination of arriving packets the algorithm
  may go into a lockstep with the out-of-sequence handling function,
  where the synch mechanism is adding a packet to the deferred queue,
  while the out-of-sequence handling is retrieving it again, thus
  ending up in a loop inside the node_lock scope.

- Even if this is avoided, the link will very often send out
  unnecessary protocol messages, in the worst case leading to
  redundant retransmissions.

We fix this by just dropping arriving packets on the upcoming link
during the synchronization phase, thus relying on the retransmission
protocol to resolve the situation once the two links have arrived to
a synchronized state.
Reviewed-by: NErik Hugne <erik.hugne@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

NLM_F_MULTI must be used only when a NLMSG_DONE message is sent. In fact,
it is sent only at the end of a dump.

Libraries like libnl will wait forever for NLMSG_DONE.

Fixes: 35b9dd76 ("tipc: add bearer get/dump to new netlink api")
Fixes: 7be57fc6 ("tipc: add link get/dump to new netlink api")
Fixes: 46f15c67 ("tipc: add media get/dump to new netlink api")
CC: Richard Alpe <richard.alpe@ericsson.com>
CC: Jon Maloy <jon.maloy@ericsson.com>
CC: Ying Xue <ying.xue@windriver.com>
CC: tipc-discussion@lists.sourceforge.net
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

NLM_F_MULTI must be used only when a NLMSG_DONE message is sent. In fact,
it is sent only at the end of a dump.

Libraries like libnl will wait forever for NLMSG_DONE.

Fixes: e5a55a89 ("net: create generic bridge ops")
Fixes: 815cccbf ("ixgbe: add setlink, getlink support to ixgbe and ixgbevf")
CC: John Fastabend <john.r.fastabend@intel.com>
CC: Sathya Perla <sathya.perla@emulex.com>
CC: Subbu Seetharaman <subbu.seetharaman@emulex.com>
CC: Ajit Khaparde <ajit.khaparde@emulex.com>
CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
CC: intel-wired-lan@lists.osuosl.org
CC: Jiri Pirko <jiri@resnulli.us>
CC: Scott Feldman <sfeldma@gmail.com>
CC: Stephen Hemminger <stephen@networkplumber.org>
CC: bridge@lists.linux-foundation.org
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

NLM_F_MULTI must be used only when a NLMSG_DONE message is sent. In fact,
it is sent only at the end of a dump.

Libraries like libnl will wait forever for NLMSG_DONE.

Fixes: 37a393bc ("bridge: notify mdb changes via netlink")
CC: Cong Wang <amwang@redhat.com>
CC: Stephen Hemminger <stephen@networkplumber.org>
CC: bridge@lists.linux-foundation.org
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This action is meant to be passive, i.e. we should not alter
skb->nfct: If nfct is present just leave it alone.

Compile tested only.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit 3cdaa5be ("ipv4: Don't
increase PMTU with Datagram Too Big message") broke PMTU in cases
where the rt_pmtu value has expired but is smaller than the new
PMTU value.

This obsolete rt_pmtu then prevents the new PMTU value from being
installed.

Fixes: 3cdaa5be ("ipv4: Don't increase PMTU with Datagram Too Big message")
Reported-by: NGerd v. Egidy <gerd.von.egidy@intra2net.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fixes:

====================
net/netfilter/nft_reject.c: In function ‘nft_reject_dump’:
net/netfilter/nft_reject.c:61:2: warning: enumeration value ‘NFT_REJECT_TCP_RST’ not handled in switch [-Wswitch]
  switch (priv->type) {
  ^
net/netfilter/nft_reject.c:61:2: warning: enumeration value ‘NFT_REJECT_ICMPX_UNREACH’ not handled in switch [-Wswi\
tch]
net/netfilter/nft_reject_inet.c: In function ‘nft_reject_inet_dump’:
net/netfilter/nft_reject_inet.c:105:2: warning: enumeration value ‘NFT_REJECT_TCP_RST’ not handled in switch [-Wswi\
tch]
  switch (priv->type) {
  ^
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 567e4b79 ("net: rfs: add hash collision detection") had one
mistake :

RPS_NO_CPU is no longer the marker for invalid cpu in set_rps_cpu()
and get_rps_cpu(), as @next_cpu was the result of an AND with
rps_cpu_mask

This bug showed up on a host with 72 cpus :
next_cpu was 0x7f, and the code was trying to access percpu data of an
non existent cpu.

In a follow up patch, we might get rid of compares against nr_cpu_ids,
if we init the tables with 0. This is silly to test for a very unlikely
condition that exists only shortly after table initialization, as
we got rid of rps_reset_sock_flow() and similar functions that were
writing this RPS_NO_CPU magic value at flow dismantle : When table is
old enough, it never contains this value anymore.

Fixes: 567e4b79 ("net: rfs: add hash collision detection")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When I added pfmemalloc support in build_skb(), I forgot netlink
was using build_skb() with a vmalloc() area.

In this patch I introduce __build_skb() for netlink use,
and build_skb() is a wrapper handling both skb->head_frag and
skb->pfmemalloc

This means netlink no longer has to hack skb->head_frag

[ 1567.700067] kernel BUG at arch/x86/mm/physaddr.c:26!
[ 1567.700067] invalid opcode: 0000 [#1] PREEMPT SMP KASAN
[ 1567.700067] Dumping ftrace buffer:
[ 1567.700067]    (ftrace buffer empty)
[ 1567.700067] Modules linked in:
[ 1567.700067] CPU: 9 PID: 16186 Comm: trinity-c182 Not tainted 4.0.0-next-20150424-sasha-00037-g4796e21 #2167
[ 1567.700067] task: ffff880127efb000 ti: ffff880246770000 task.ti: ffff880246770000
[ 1567.700067] RIP: __phys_addr (arch/x86/mm/physaddr.c:26 (discriminator 3))
[ 1567.700067] RSP: 0018:ffff8802467779d8  EFLAGS: 00010202
[ 1567.700067] RAX: 000041000ed8e000 RBX: ffffc9008ed8e000 RCX: 000000000000002c
[ 1567.700067] RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffffffb3fd6049
[ 1567.700067] RBP: ffff8802467779f8 R08: 0000000000000019 R09: ffff8801d0168000
[ 1567.700067] R10: ffff8801d01680c7 R11: ffffed003a02d019 R12: ffffc9000ed8e000
[ 1567.700067] R13: 0000000000000f40 R14: 0000000000001180 R15: ffffc9000ed8e000
[ 1567.700067] FS:  00007f2a7da3f700(0000) GS:ffff8801d1000000(0000) knlGS:0000000000000000
[ 1567.700067] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1567.700067] CR2: 0000000000738308 CR3: 000000022e329000 CR4: 00000000000007e0
[ 1567.700067] Stack:
[ 1567.700067]  ffffc9000ed8e000 ffff8801d0168000 ffffc9000ed8e000 ffff8801d0168000
[ 1567.700067]  ffff880246777a28 ffffffffad7c0a21 0000000000001080 ffff880246777c08
[ 1567.700067]  ffff88060d302e68 ffff880246777b58 ffff880246777b88 ffffffffad9a6821
[ 1567.700067] Call Trace:
[ 1567.700067] build_skb (include/linux/mm.h:508 net/core/skbuff.c:316)
[ 1567.700067] netlink_sendmsg (net/netlink/af_netlink.c:1633 net/netlink/af_netlink.c:2329)
[ 1567.774369] ? sched_clock_cpu (kernel/sched/clock.c:311)
[ 1567.774369] ? netlink_unicast (net/netlink/af_netlink.c:2273)
[ 1567.774369] ? netlink_unicast (net/netlink/af_netlink.c:2273)
[ 1567.774369] sock_sendmsg (net/socket.c:614 net/socket.c:623)
[ 1567.774369] sock_write_iter (net/socket.c:823)
[ 1567.774369] ? sock_sendmsg (net/socket.c:806)
[ 1567.774369] __vfs_write (fs/read_write.c:479 fs/read_write.c:491)
[ 1567.774369] ? get_lock_stats (kernel/locking/lockdep.c:249)
[ 1567.774369] ? default_llseek (fs/read_write.c:487)
[ 1567.774369] ? vtime_account_user (kernel/sched/cputime.c:701)
[ 1567.774369] ? rw_verify_area (fs/read_write.c:406 (discriminator 4))
[ 1567.774369] vfs_write (fs/read_write.c:539)
[ 1567.774369] SyS_write (fs/read_write.c:586 fs/read_write.c:577)
[ 1567.774369] ? SyS_read (fs/read_write.c:577)
[ 1567.774369] ? __this_cpu_preempt_check (lib/smp_processor_id.c:63)
[ 1567.774369] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2594 kernel/locking/lockdep.c:2636)
[ 1567.774369] ? trace_hardirqs_on_thunk (arch/x86/lib/thunk_64.S:42)
[ 1567.774369] system_call_fastpath (arch/x86/kernel/entry_64.S:261)

Fixes: 79930f58 ("net: do not deplete pfmemalloc reserve")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>