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This work adds the DataCenter TCP (DCTCP) congestion control
algorithm [1], which has been first published at SIGCOMM 2010 [2],
resp. follow-up analysis at SIGMETRICS 2011 [3] (and also, more
recently as an informational IETF draft available at [4]).
DCTCP is an enhancement to the TCP congestion control algorithm for
data center networks. Typical data center workloads are i.e.
i) partition/aggregate (queries; bursty, delay sensitive), ii) short
messages e.g. 50KB-1MB (for coordination and control state; delay
sensitive), and iii) large flows e.g. 1MB-100MB (data update;
throughput sensitive). DCTCP has therefore been designed for such
environments to provide/achieve the following three requirements:
* High burst tolerance (incast due to partition/aggregate)
* Low latency (short flows, queries)
* High throughput (continuous data updates, large file
transfers) with commodity, shallow buffered switches
The basic idea of its design consists of two fundamentals: i) on the
switch side, packets are being marked when its internal queue
length > threshold K (K is chosen so that a large enough headroom
for marked traffic is still available in the switch queue); ii) the
sender/host side maintains a moving average of the fraction of marked
packets, so each RTT, F is being updated as follows:
F := X / Y, where X is # of marked ACKs, Y is total # of ACKs
alpha := (1 - g) * alpha + g * F, where g is a smoothing constant
The resulting alpha (iow: probability that switch queue is congested)
is then being used in order to adaptively decrease the congestion
window W:
W := (1 - (alpha / 2)) * W
The means for receiving marked packets resp. marking them on switch
side in DCTCP is the use of ECN.
RFC3168 describes a mechanism for using Explicit Congestion Notification
from the switch for early detection of congestion, rather than waiting
for segment loss to occur.
However, this method only detects the presence of congestion, not
the *extent*. In the presence of mild congestion, it reduces the TCP
congestion window too aggressively and unnecessarily affects the
throughput of long flows [4].
DCTCP, as mentioned, enhances Explicit Congestion Notification (ECN)
processing to estimate the fraction of bytes that encounter congestion,
rather than simply detecting that some congestion has occurred. DCTCP
then scales the TCP congestion window based on this estimate [4],
thus it can derive multibit feedback from the information present in
the single-bit sequence of marks in its control law. And thus act in
*proportion* to the extent of congestion, not its *presence*.
Switches therefore set the Congestion Experienced (CE) codepoint in
packets when internal queue lengths exceed threshold K. Resulting,
DCTCP delivers the same or better throughput than normal TCP, while
using 90% less buffer space.
It was found in [2] that DCTCP enables the applications to handle 10x
the current background traffic, without impacting foreground traffic.
Moreover, a 10x increase in foreground traffic did not cause any
timeouts, and thus largely eliminates TCP incast collapse problems.
The algorithm itself has already seen deployments in large production
data centers since then.
We did a long-term stress-test and analysis in a data center, short
summary of our TCP incast tests with iperf compared to cubic:
This test measured DCTCP throughput and latency and compared it with
CUBIC throughput and latency for an incast scenario. In this test, 19
senders sent at maximum rate to a single receiver. The receiver simply
ran iperf -s.
The senders ran iperf -c <receiver> -t 30. All senders started
simultaneously (using local clocks synchronized by ntp).
This test was repeated multiple times. Below shows the results from a
single test. Other tests are similar. (DCTCP results were extremely
consistent, CUBIC results show some variance induced by the TCP timeouts
that CUBIC encountered.)
For this test, we report statistics on the number of TCP timeouts,
flow throughput, and traffic latency.
1) Timeouts (total over all flows, and per flow summaries):
CUBIC DCTCP
Total 3227 25
Mean 169.842 1.316
Median 183 1
Max 207 5
Min 123 0
Stddev 28.991 1.600
Timeout data is taken by measuring the net change in netstat -s
"other TCP timeouts" reported. As a result, the timeout measurements
above are not restricted to the test traffic, and we believe that it
is likely that all of the "DCTCP timeouts" are actually timeouts for
non-test traffic. We report them nevertheless. CUBIC will also include
some non-test timeouts, but they are drawfed by bona fide test traffic
timeouts for CUBIC. Clearly DCTCP does an excellent job of preventing
TCP timeouts. DCTCP reduces timeouts by at least two orders of
magnitude and may well have eliminated them in this scenario.
2) Throughput (per flow in Mbps):
CUBIC DCTCP
Mean 521.684 521.895
Median 464 523
Max 776 527
Min 403 519
Stddev 105.891 2.601
Fairness 0.962 0.999
Throughput data was simply the average throughput for each flow
reported by iperf. By avoiding TCP timeouts, DCTCP is able to
achieve much better per-flow results. In CUBIC, many flows
experience TCP timeouts which makes flow throughput unpredictable and
unfair. DCTCP, on the other hand, provides very clean predictable
throughput without incurring TCP timeouts. Thus, the standard deviation
of CUBIC throughput is dramatically higher than the standard deviation
of DCTCP throughput.
Mean throughput is nearly identical because even though cubic flows
suffer TCP timeouts, other flows will step in and fill the unused
bandwidth. Note that this test is something of a best case scenario
for incast under CUBIC: it allows other flows to fill in for flows
experiencing a timeout. Under situations where the receiver is issuing
requests and then waiting for all flows to complete, flows cannot fill
in for timed out flows and throughput will drop dramatically.
3) Latency (in ms):
CUBIC DCTCP
Mean 4.0088 0.04219
Median 4.055 0.0395
Max 4.2 0.085
Min 3.32 0.028
Stddev 0.1666 0.01064
Latency for each protocol was computed by running "ping -i 0.2
<receiver>" from a single sender to the receiver during the incast
test. For DCTCP, "ping -Q 0x6 -i 0.2 <receiver>" was used to ensure
that traffic traversed the DCTCP queue and was not dropped when the
queue size was greater than the marking threshold. The summary
statistics above are over all ping metrics measured between the single
sender, receiver pair.
The latency results for this test show a dramatic difference between
CUBIC and DCTCP. CUBIC intentionally overflows the switch buffer
which incurs the maximum queue latency (more buffer memory will lead
to high latency.) DCTCP, on the other hand, deliberately attempts to
keep queue occupancy low. The result is a two orders of magnitude
reduction of latency with DCTCP - even with a switch with relatively
little RAM. Switches with larger amounts of RAM will incur increasing
amounts of latency for CUBIC, but not for DCTCP.
4) Convergence and stability test:
This test measured the time that DCTCP took to fairly redistribute
bandwidth when a new flow commences. It also measured DCTCP's ability
to remain stable at a fair bandwidth distribution. DCTCP is compared
with CUBIC for this test.
At the commencement of this test, a single flow is sending at maximum
rate (near 10 Gbps) to a single receiver. One second after that first
flow commences, a new flow from a distinct server begins sending to
the same receiver as the first flow. After the second flow has sent
data for 10 seconds, the second flow is terminated. The first flow
sends for an additional second. Ideally, the bandwidth would be evenly
shared as soon as the second flow starts, and recover as soon as it
stops.
The results of this test are shown below. Note that the flow bandwidth
for the two flows was measured near the same time, but not
simultaneously.
DCTCP performs nearly perfectly within the measurement limitations
of this test: bandwidth is quickly distributed fairly between the two
flows, remains stable throughout the duration of the test, and
recovers quickly. CUBIC, in contrast, is slow to divide the bandwidth
fairly, and has trouble remaining stable.
CUBIC DCTCP
Seconds Flow 1 Flow 2 Seconds Flow 1 Flow 2
0 9.93 0 0 9.92 0
0.5 9.87 0 0.5 9.86 0
1 8.73 2.25 1 6.46 4.88
1.5 7.29 2.8 1.5 4.9 4.99
2 6.96 3.1 2 4.92 4.94
2.5 6.67 3.34 2.5 4.93 5
3 6.39 3.57 3 4.92 4.99
3.5 6.24 3.75 3.5 4.94 4.74
4 6 3.94 4 5.34 4.71
4.5 5.88 4.09 4.5 4.99 4.97
5 5.27 4.98 5 4.83 5.01
5.5 4.93 5.04 5.5 4.89 4.99
6 4.9 4.99 6 4.92 5.04
6.5 4.93 5.1 6.5 4.91 4.97
7 4.28 5.8 7 4.97 4.97
7.5 4.62 4.91 7.5 4.99 4.82
8 5.05 4.45 8 5.16 4.76
8.5 5.93 4.09 8.5 4.94 4.98
9 5.73 4.2 9 4.92 5.02
9.5 5.62 4.32 9.5 4.87 5.03
10 6.12 3.2 10 4.91 5.01
10.5 6.91 3.11 10.5 4.87 5.04
11 8.48 0 11 8.49 4.94
11.5 9.87 0 11.5 9.9 0
SYN/ACK ECT test:
This test demonstrates the importance of ECT on SYN and SYN-ACK packets
by measuring the connection probability in the presence of competing
flows for a DCTCP connection attempt *without* ECT in the SYN packet.
The test was repeated five times for each number of competing flows.
Competing Flows 1 | 2 | 4 | 8 | 16
------------------------------
Mean Connection Probability 1 | 0.67 | 0.45 | 0.28 | 0
Median Connection Probability 1 | 0.65 | 0.45 | 0.25 | 0
As the number of competing flows moves beyond 1, the connection
probability drops rapidly.
Enabling DCTCP with this patch requires the following steps:
DCTCP must be running both on the sender and receiver side in your
data center, i.e.:
sysctl -w net.ipv4.tcp_congestion_control=dctcp
Also, ECN functionality must be enabled on all switches in your
data center for DCTCP to work. The default ECN marking threshold (K)
heuristic on the switch for DCTCP is e.g., 20 packets (30KB) at
1Gbps, and 65 packets (~100KB) at 10Gbps (K > 1/7 * C * RTT, [4]).
In above tests, for each switch port, traffic was segregated into two
queues. For any packet with a DSCP of 0x01 - or equivalently a TOS of
0x04 - the packet was placed into the DCTCP queue. All other packets
were placed into the default drop-tail queue. For the DCTCP queue,
RED/ECN marking was enabled, here, with a marking threshold of 75 KB.
More details however, we refer you to the paper [2] under section 3).
There are no code changes required to applications running in user
space. DCTCP has been implemented in full *isolation* of the rest of
the TCP code as its own congestion control module, so that it can run
without a need to expose code to the core of the TCP stack, and thus
nothing changes for non-DCTCP users.
Changes in the CA framework code are minimal, and DCTCP algorithm
operates on mechanisms that are already available in most Silicon.
The gain (dctcp_shift_g) is currently a fixed constant (1/16) from
the paper, but we leave the option that it can be chosen carefully
to a different value by the user.
In case DCTCP is being used and ECN support on peer site is off,
DCTCP falls back after 3WHS to operate in normal TCP Reno mode.
ss {-4,-6} -t -i diag interface:
... dctcp wscale:7,7 rto:203 rtt:2.349/0.026 mss:1448 cwnd:2054
ssthresh:1102 ce_state 0 alpha 15 ab_ecn 0 ab_tot 735584
send 10129.2Mbps pacing_rate 20254.1Mbps unacked:1822 retrans:0/15
reordering:101 rcv_space:29200
... dctcp-reno wscale:7,7 rto:201 rtt:0.711/1.327 ato:40 mss:1448
cwnd:10 ssthresh:1102 fallback_mode send 162.9Mbps pacing_rate
325.5Mbps rcv_rtt:1.5 rcv_space:29200
More information about DCTCP can be found in [1-4].
[1] http://simula.stanford.edu/~alizade/Site/DCTCP.html
[2] http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp-final.pdf
[3] http://simula.stanford.edu/~alizade/Site/DCTCP_files/dctcp_analysis-full.pdf
[4] http://tools.ietf.org/html/draft-bensley-tcpm-dctcp-00
Joint work with Florian Westphal and Glenn Judd.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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DataCenter TCP (DCTCP) determines cwnd growth based on ECN information
and ACK properties, e.g. ACK that updates window is treated differently
than DUPACK.
Also DCTCP needs information whether ACK was delayed ACK. Furthermore,
DCTCP also implements a CE state machine that keeps track of CE markings
of incoming packets.
Therefore, extend the congestion control framework to provide these
event types, so that DCTCP can be properly implemented as a normal
congestion algorithm module outside of the core stack.
Joint work with Daniel Borkmann and Glenn Judd.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The congestion control ops "cwnd_event" currently supports
CA_EVENT_FAST_ACK and CA_EVENT_SLOW_ACK events (among others).
Both FAST and SLOW_ACK are only used by Westwood congestion
control algorithm.
This removes both flags from cwnd_event and adds a new
in_ack_event callback for this. The goal is to be able to
provide more detailed information about ACKs, such as whether
ECE flag was set, or whether the ACK resulted in a window
update.
It is required for DataCenter TCP (DCTCP) congestion control
algorithm as it makes a different choice depending on ECE being
set or not.
Joint work with Daniel Borkmann and Glenn Judd.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch adds a flag to TCP congestion algorithms that allows
for requesting to mark IPv4/IPv6 sockets with transport as ECN
capable, that is, ECT(0), when required by a congestion algorithm.
It is currently used and needed in DataCenter TCP (DCTCP), as it
requires both peers to assert ECT on all IP packets sent - it
uses ECN feedback (i.e. CE, Congestion Encountered information)
from switches inside the data center to derive feedback to the
end hosts.
Therefore, simply add a new flag to icsk_ca_ops. Note that DCTCP's
algorithm/behaviour slightly diverges from RFC3168, therefore this
is only (!) enabled iff the assigned congestion control ops module
has requested this. By that, we can tightly couple this logic really
only to the provided congestion control ops.
Joint work with Florian Westphal and Glenn Judd.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Split assignment and initialization from one into two functions.
This is required by followup patches that add Datacenter TCP
(DCTCP) congestion control algorithm - we need to be able to
determine if the connection is moderated by DCTCP before the
3WHS has finished.
As we walk the available congestion control list during the
assignment, we are always guaranteed to have Reno present as
it's fixed compiled-in. Therefore, since we're doing the
early assignment, we don't have a real use for the Reno alias
tcp_init_congestion_ops anymore and can thus remove it.
Actual usage of the congestion control operations are being
made after the 3WHS has finished, in some cases however we
can access get_info() via diag if implemented, therefore we
need to zero out the private area for those modules.
Joint work with Daniel Borkmann and Glenn Judd.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Glenn Judd <glenn.judd@morganstanley.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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While doing high throughput test on a BQL enabled NIC,
I found a very high cost in ndo_start_xmit() when accessing BQL data.
It turned out the problem was caused by compiler trying to be
smart, but involving a bad MESI transaction :
0.05 │ mov 0xc0(%rax),%edi // LOAD dql->num_queued
0.48 │ mov %edx,0xc8(%rax) // STORE dql->last_obj_cnt = count
58.23 │ add %edx,%edi
0.58 │ cmp %edi,0xc4(%rax)
0.76 │ mov %edi,0xc0(%rax) // STORE dql->num_queued += count
0.72 │ js bd8
I got an incredible 10 % gain [1] by making sure cpu do not attempt
to get the cache line in Shared mode, but directly requests for
ownership.
New code :
mov %edx,0xc8(%rax) // STORE dql->last_obj_cnt = count
add %edx,0xc0(%rax) // RMW dql->num_queued += count
mov 0xc4(%rax),%ecx // LOAD dql->adj_limit
mov 0xc0(%rax),%edx // LOAD dql->num_queued
cmp %edx,%ecx
The TX completion was running from another cpu, with high interrupts
rate.
Note that I am using barrier() as a soft hint, as mb() here could be
too heavy cost.
[1] This was a netperf TCP_STREAM with TSO disabled, but GSO enabled.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim <hadi@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next
Steffen Klassert says:
====================
pull request (net-next): ipsec-next 2014-09-25
1) Remove useless hash_resize_mutex in xfrm_hash_resize().
This mutex is used only there, but xfrm_hash_resize()
can't be called concurrently at all. From Ying Xue.
2) Extend policy hashing to prefixed policies based on
prefix lenght thresholds. From Christophe Gouault.
3) Make the policy hash table thresholds configurable
via netlink. From Christophe Gouault.
4) Remove the maximum authentication length for AH.
This was needed to limit stack usage. We switched
already to allocate space, so no need to keep the
limit. From Herbert Xu.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Allow switches driver to query and enable/disable EEE on a per-port
basis by implementing the ethtool_{get,set}_eee settings and delegating
these operations to the switch driver.
set_eee() will need to coordinate with the PHY driver to make sure that
EEE is enabled, the link-partner supports it and the auto-negotiation
result is satisfactory.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Whenever a per-port network device is used/unused, invoke the switch
driver port_enable/port_disable callbacks to allow saving as much power
as possible by disabling unused parts of the switch (RX/TX logic, memory
arrays, PHYs...). We supply a PHY device argument to make sure the
switch driver can act on the PHY device if needed (like putting/taking
the PHY out of deep low power mode).
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Our goal is to access no more than one cache line access per skb in
a write or receive queue when doing the various walks.
After recent TCP_SKB_CB() reorganizations, it is almost done.
Last part is tcp_skb_pcount() which currently uses
skb_shinfo(skb)->gso_segs, which is a terrible choice, because it needs
3 cache lines in current kernel (skb->head, skb->end, and
shinfo->gso_segs are all in 3 different cache lines, far from skb->cb)
This very simple patch reuses space currently taken by tcp_tw_isn
only in input path, as tcp_skb_pcount is only needed for skb stored in
write queue.
This considerably speeds up tcp_ack(), granted we avoid shinfo->tx_flags
to get SKBTX_ACK_TSTAMP, which seems possible.
This also speeds up all sack processing in general.
This speeds up tcp_sendmsg() because it no longer has to access/dirty
shinfo.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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TCP maintains lists of skb in write queue, and in receive queues
(in order and out of order queues)
Scanning these lists both in input and output path usually requires
access to skb->next, TCP_SKB_CB(skb)->seq, and TCP_SKB_CB(skb)->end_seq
These fields are currently in two different cache lines, meaning we
waste lot of memory bandwidth when these queues are big and flows
have either packet drops or packet reorders.
We can move TCP_SKB_CB(skb)->header at the end of TCP_SKB_CB, because
this header is not used in fast path. This allows TCP to search much faster
in the skb lists.
Even with regular flows, we save one cache line miss in fast path.
Thanks to Christoph Paasch for noticing we need to cleanup
skb->cb[] (IPCB/IP6CB) before entering IP stack in tx path,
and that I forgot IPCB use in tcp_v4_hnd_req() and tcp_v4_save_options().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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ipv6_opt_accepted() assumes IP6CB(skb) holds the struct inet6_skb_parm
that it needs. Lets not assume this, as TCP stack might use a different
place.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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ip_options_echo() assumes struct ip_options is provided in &IPCB(skb)->opt
Lets break this assumption, but provide a helper to not change all call points.
ip_send_unicast_reply() gets a new struct ip_options pointer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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csum_partial() is a generic function which is not optimised for small fixed
length calculations, and its use requires to store "from" and "to" values in
memory while we already have them available in registers. This also has impact,
especially on RISC processors. In the same spirit as the change done by
Eric Dumazet on csum_replace2(), this patch rewrites inet_proto_csum_replace4()
taking into account RFC1624.
I spotted during a NATted tcp transfert that csum_partial() is one of top 5
consuming functions (around 8%), and the second user of csum_partial() is
inet_proto_csum_replace4().
I have proposed the same modification to inet_proto_csum_replace4() in another
patch.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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While profiling TCP stack, I noticed one useless atomic operation
in tcp_sendmsg(), caused by skb_header_release().
It turns out all current skb_header_release() users have a fresh skb,
that no other user can see, so we can avoid one atomic operation.
Introduce __skb_header_release() to clearly document this.
This gave me a 1.5 % improvement on TCP_RR workload.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next
John W. Linville says:
====================
pull request: wireless-next 2014-09-22
Please pull this batch of updates intended for the 3.18 stream...
For the mac80211 bits, Johannes says:
"This time, I have some rate minstrel improvements, support for a very
small feature from CCX that Steinar reverse-engineered, dynamic ACK
timeout support, a number of changes for TDLS, early support for radio
resource measurement and many fixes. Also, I'm changing a number of
places to clear key memory when it's freed and Intel claims copyright
for code they developed."
For the bluetooth bits, Johan says:
"Here are some more patches intended for 3.18. Most of them are cleanups
or fixes for SMP. The only exception is a fix for BR/EDR L2CAP fixed
channels which should now work better together with the L2CAP
information request procedure."
For the iwlwifi bits, Emmanuel says:
"I fix here dvm which was broken by my last pull request. Arik
continues to work on TDLS and Luca solved a few issues in CT-Kill. Eyal
keeps digging into rate scaling code, more to come soon. Besides this,
nothing really special here."
Beyond that, there are the usual big batches of updates to ath9k, b43,
mwifiex, and wil6210 as well as a handful of other bits here and there.
Also, rtlwifi gets some btcoexist attention from Larry.
Please let me know if there are problems!
====================
Had to adjust the wil6210 code to comply with Joe Perches's recent
change in net-next to make the netdev_*() routines return void instead
of 'int'.
Signed-off-by: David S. Miller <davem@davemloft.net>
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No caller or macro uses the return value so make all
the functions return void.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch adds verifier core which simulates execution of every insn and
records the state of registers and program stack. Every branch instruction seen
during simulation is pushed into state stack. When verifier reaches BPF_EXIT,
it pops the state from the stack and continues until it reaches BPF_EXIT again.
For program:
1: bpf_mov r1, xxx
2: if (r1 == 0) goto 5
3: bpf_mov r0, 1
4: goto 6
5: bpf_mov r0, 2
6: bpf_exit
The verifier will walk insns: 1, 2, 3, 4, 6
then it will pop the state recorded at insn#2 and will continue: 5, 6
This way it walks all possible paths through the program and checks all
possible values of registers. While doing so, it checks for:
- invalid instructions
- uninitialized register access
- uninitialized stack access
- misaligned stack access
- out of range stack access
- invalid calling convention
- instruction encoding is not using reserved fields
Kernel subsystem configures the verifier with two callbacks:
- bool (*is_valid_access)(int off, int size, enum bpf_access_type type);
that provides information to the verifer which fields of 'ctx'
are accessible (remember 'ctx' is the first argument to eBPF program)
- const struct bpf_func_proto *(*get_func_proto)(enum bpf_func_id func_id);
returns argument constraints of kernel helper functions that eBPF program
may call, so that verifier can checks that R1-R5 types match the prototype
More details in Documentation/networking/filter.txt and in kernel/bpf/verifier.c
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
eBPF programs passed from userspace are using pseudo BPF_LD_IMM64 instructions
to refer to process-local map_fd. Scan the program for such instructions and
if FDs are valid, convert them to 'struct bpf_map' pointers which will be used
by verifier to check access to maps in bpf_map_lookup/update() calls.
If program passes verifier, convert pseudo BPF_LD_IMM64 into generic by dropping
BPF_PSEUDO_MAP_FD flag.
Note that eBPF interpreter is generic and knows nothing about pseudo insns.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
add optional attributes for BPF_PROG_LOAD syscall:
union bpf_attr {
struct {
...
__u32 log_level; /* verbosity level of eBPF verifier */
__u32 log_size; /* size of user buffer */
__aligned_u64 log_buf; /* user supplied 'char *buffer' */
};
};
when log_level > 0 the verifier will return its verification log in the user
supplied buffer 'log_buf' which can be used by program author to analyze why
verifier rejected given program.
'Understanding eBPF verifier messages' section of Documentation/networking/filter.txt
provides several examples of these messages, like the program:
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_CALL_FUNC(BPF_FUNC_map_lookup_elem),
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
BPF_ST_MEM(BPF_DW, BPF_REG_0, 4, 0),
BPF_EXIT_INSN(),
will be rejected with the following multi-line message in log_buf:
0: (7a) *(u64 *)(r10 -8) = 0
1: (bf) r2 = r10
2: (07) r2 += -8
3: (b7) r1 = 0
4: (85) call 1
5: (15) if r0 == 0x0 goto pc+1
R0=map_ptr R10=fp
6: (7a) *(u64 *)(r0 +4) = 0
misaligned access off 4 size 8
The format of the output can change at any time as verifier evolves.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
this patch adds all of eBPF verfier documentation and empty bpf_check()
The end goal for the verifier is to statically check safety of the program.
Verifier will catch:
- loops
- out of range jumps
- unreachable instructions
- invalid instructions
- uninitialized register access
- uninitialized stack access
- misaligned stack access
- out of range stack access
- invalid calling convention
More details in Documentation/networking/filter.txt
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
eBPF programs are similar to kernel modules. They are loaded by the user
process and automatically unloaded when process exits. Each eBPF program is
a safe run-to-completion set of instructions. eBPF verifier statically
determines that the program terminates and is safe to execute.
The following syscall wrapper can be used to load the program:
int bpf_prog_load(enum bpf_prog_type prog_type,
const struct bpf_insn *insns, int insn_cnt,
const char *license)
{
union bpf_attr attr = {
.prog_type = prog_type,
.insns = ptr_to_u64(insns),
.insn_cnt = insn_cnt,
.license = ptr_to_u64(license),
};
return bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
}
where 'insns' is an array of eBPF instructions and 'license' is a string
that must be GPL compatible to call helper functions marked gpl_only
Upon succesful load the syscall returns prog_fd.
Use close(prog_fd) to unload the program.
User space tests and examples follow in the later patches
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
'maps' is a generic storage of different types for sharing data between kernel
and userspace.
The maps are accessed from user space via BPF syscall, which has commands:
- create a map with given type and attributes
fd = bpf(BPF_MAP_CREATE, union bpf_attr *attr, u32 size)
returns fd or negative error
- lookup key in a given map referenced by fd
err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)
using attr->map_fd, attr->key, attr->value
returns zero and stores found elem into value or negative error
- create or update key/value pair in a given map
err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)
using attr->map_fd, attr->key, attr->value
returns zero or negative error
- find and delete element by key in a given map
err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)
using attr->map_fd, attr->key
- iterate map elements (based on input key return next_key)
err = bpf(BPF_MAP_GET_NEXT_KEY, union bpf_attr *attr, u32 size)
using attr->map_fd, attr->key, attr->next_key
- close(fd) deletes the map
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
done as separate commit to ease conflict resolution
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
BPF syscall is a multiplexor for a range of different operations on eBPF.
This patch introduces syscall with single command to create a map.
Next patch adds commands to access maps.
'maps' is a generic storage of different types for sharing data between kernel
and userspace.
Userspace example:
/* this syscall wrapper creates a map with given type and attributes
* and returns map_fd on success.
* use close(map_fd) to delete the map
*/
int bpf_create_map(enum bpf_map_type map_type, int key_size,
int value_size, int max_entries)
{
union bpf_attr attr = {
.map_type = map_type,
.key_size = key_size,
.value_size = value_size,
.max_entries = max_entries
};
return bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}
'union bpf_attr' is backwards compatible with future extensions.
More details in Documentation/networking/filter.txt and in manpage
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
The send_check logic was only interesting in cases of TCP offload and
UDP UFO where the checksum needed to be initialized to the pseudo
header checksum. Now we've moved that logic into the related
gso_segment functions so gso_send_check is no longer needed.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
|
|
Pull one last block fix from Jens Axboe:
"We've had an issue with scsi-mq where probing takes forever. This was
bisected down to the percpu changes for blk_mq_queue_enter(), and the
fact we now suffer an RCU grace period when killing a queue. SCSI
creates and destroys tons of queues, so this let to 10s of seconds of
stalls at boot for some.
Tejun has a real fix for this, but it's too involved for 3.17. So
this is a temporary workaround to expedite the queue killing until we
can fold in the real fix for 3.18 when that merge window opens"
* 'for-linus' of git://git.kernel.dk/linux-block:
blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe
|
|
Pull crypto fixes from Herbert Xu:
"This fixes three issues:
- if ccp is loaded on a machine without ccp, it will incorrectly
activate causing all requests to fail. Fixed by preventing ccp
from loading if hardware isn't available.
- not all IRQs were enabled for the qat driver, leading to potential
stalls when it is used
- disabled buggy AVX CTR implementation in aesni"
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: aesni - disable "by8" AVX CTR optimization
crypto: ccp - Check for CCP before registering crypto algs
crypto: qat - Enable all 32 IRQs
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media fixes from Mauro Carvalho Chehab:
"For some last time fixes:
- a regression detected on Kernel 3.16 related to VBI Teletext
application breakage on drivers using videobuf2 (see
https://bugzilla.kernel.org/show_bug.cgi?id=84401). The bug was
noticed on saa7134 (migrated to VB2 on 3.16), but also affects
em28xx (migrated on 3.9 to VB2);
- two additional sanity checks at videobuf2;
- two fixups to restore proper VBI support at the em28xx driver;
- two Kernel oops fixups (at cx24123 and cx2341x drivers);
- a bug at adv7604 where an if was doing just the opposite as it
would be expected;
- some documentation fixups to match the behavior defined at the
Kernel"
* tag 'media/v3.17-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
[media] em28xx-v4l: get rid of field "users" in struct em28xx_v4l2"
[media] em28xx: fix VBI handling logic
[media] DocBook media: improve the poll() documentation
[media] DocBook media: fix the poll() 'no QBUF' documentation
[media] vb2: fix VBI/poll regression
[media] cx2341x: fix kernel oops
[media] cx24123: fix kernel oops due to missing parent pointer
[media] adv7604: fix inverted condition
[media] media/radio: fix radio-miropcm20.c build with io.h header file
[media] vb2: fix plane index sanity check in vb2_plane_cookie()
[media] DocBook media: update version number and V4L2 changes
[media] DocBook media: fix fieldname in struct v4l2_subdev_selection
[media] vb2: fix vb2 state check when start_streaming fails
[media] videobuf2-core.h: fix comment
[media] videobuf2-core: add comments before the WARN_ON
[media] videobuf2-dma-sg: fix for wrong GFP mask to sg_alloc_table_from_pages
|
|
blk-mq uses percpu_ref for its usage counter which tracks the number
of in-flight commands and used to synchronously drain the queue on
freeze. percpu_ref shutdown takes measureable wallclock time as it
involves a sched RCU grace period. This means that draining a blk-mq
takes measureable wallclock time. One would think that this shouldn't
matter as queue shutdown should be a rare event which takes place
asynchronously w.r.t. userland.
Unfortunately, SCSI probing involves synchronously setting up and then
tearing down a lot of request_queues back-to-back for non-existent
LUNs. This means that SCSI probing may take more than ten seconds
when scsi-mq is used.
This will be properly fixed by implementing a mechanism to keep
q->mq_usage_counter in atomic mode till genhd registration; however,
that involves rather big updates to percpu_ref which is difficult to
apply late in the devel cycle (v3.17-rc6 at the moment). As a
stop-gap measure till the proper fix can be implemented in the next
cycle, this patch introduces __percpu_ref_kill_expedited() and makes
blk_mq_freeze_queue() use it. This is heavy-handed but should work
for testing the experimental SCSI blk-mq implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Christoph Hellwig <hch@infradead.org>
Link: http://lkml.kernel.org/g/20140919113815.GA10791@lst.de
Fixes: add703fda981 ("blk-mq: use percpu_ref for mq usage count")
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
If the ccp is built as a built-in module, then ccp-crypto (whether
built as a module or a built-in module) will be able to load and
it will register its crypto algorithms. If the system does not have
a CCP this will result in -ENODEV being returned whenever a command
is attempted to be queued by the registered crypto algorithms.
Add an API, ccp_present(), that checks for the presence of a CCP
on the system. The ccp-crypto module can use this to determine if it
should register it's crypto alogorithms.
Cc: stable@vger.kernel.org
Reported-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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|
git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband
Pull infiniband/rdma fixes from Roland Dreier:
"Last late set of InfiniBand/RDMA fixes for 3.17:
- fixes for the new memory region re-registration support
- iSER initiator error path fixes
- grab bag of small fixes for the qib and ocrdma hardware drivers
- larger set of fixes for mlx4, especially in RoCE mode"
* tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband: (26 commits)
IB/mlx4: Fix VF mac handling in RoCE
IB/mlx4: Do not allow APM under RoCE
IB/mlx4: Don't update QP1 in native mode
IB/mlx4: Avoid accessing netdevice when building RoCE qp1 header
mlx4: Fix mlx4 reg/unreg mac to work properly with 0-mac addresses
IB/core: When marshaling uverbs path, clear unused fields
IB/mlx4: Avoid executing gid task when device is being removed
IB/mlx4: Fix lockdep splat for the iboe lock
IB/mlx4: Get upper dev addresses as RoCE GIDs when port comes up
IB/mlx4: Reorder steps in RoCE GID table initialization
IB/mlx4: Don't duplicate the default RoCE GID
IB/mlx4: Avoid null pointer dereference in mlx4_ib_scan_netdevs()
IB/iser: Bump version to 1.4.1
IB/iser: Allow bind only when connection state is UP
IB/iser: Fix RX/TX CQ resource leak on error flow
RDMA/ocrdma: Use right macro in query AH
RDMA/ocrdma: Resolve L2 address when creating user AH
mlx4: Correct error flows in rereg_mr
IB/qib: Correct reference counting in debugfs qp_stats
IPoIB: Remove unnecessary port query
...
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Current ICMP rate limiting uses inetpeer cache, which is an RBL tree
protected by a lock, meaning that hosts can be stuck hard if all cpus
want to check ICMP limits.
When say a DNS or NTP server process is restarted, inetpeer tree grows
quick and machine comes to its knees.
iptables can not help because the bottleneck happens before ICMP
messages are even cooked and sent.
This patch adds a new global limitation, using a token bucket filter,
controlled by two new sysctl :
icmp_msgs_per_sec - INTEGER
Limit maximal number of ICMP packets sent per second from this host.
Only messages whose type matches icmp_ratemask are
controlled by this limit.
Default: 1000
icmp_msgs_burst - INTEGER
icmp_msgs_per_sec controls number of ICMP packets sent per second,
while icmp_msgs_burst controls the burst size of these packets.
Default: 50
Note that if we really want to send millions of ICMP messages per
second, we might extend idea and infra added in commit 04ca6973f7c1a
("ip: make IP identifiers less predictable") :
add a token bucket in the ip_idents hash and no longer rely on inetpeer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Conflicts:
arch/mips/net/bpf_jit.c
drivers/net/can/flexcan.c
Both the flexcan and MIPS bpf_jit conflicts were cases of simple
overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pull networking fixes from David Miller:
1) If the user gives us a msg_namelen of 0, don't try to interpret
anything pointed to by msg_name. From Ani Sinha.
2) Fix some bnx2i/bnx2fc randconfig compilation errors.
The gist of the issue is that we firstly have drivers that span both
SCSI and networking. And at the top of that chain of dependencies
we have things like SCSI_FC_ATTRS and SCSI_NETLINK which are
selected.
But since select is a sledgehammer and ignores dependencies,
everything to select's SCSI_FC_ATTRS and/or SCSI_NETLINK has to also
explicitly select their dependencies and so on and so forth.
Generally speaking 'select' is supposed to only be used for child
nodes, those which have no dependencies of their own. And this
whole chain of dependencies in the scsi layer violates that rather
strongly.
So just make SCSI_NETLINK depend upon it's dependencies, and so on
and so forth for the things selecting it (either directly or
indirectly).
From Anish Bhatt and Randy Dunlap.
3) Fix generation of blackhole routes in IPSEC, from Steffen Klassert.
4) Actually notice netdev feature changes in rtl_open() code, from
Hayes Wang.
5) Fix divide by zero in bond enslaving, from Nikolay Aleksandrov.
6) Missing memory barrier in sunvnet driver, from David Stevens.
7) Don't leave anycast addresses around when ipv6 interface is
destroyed, from Sabrina Dubroca.
8) Don't call efx_{arch}_filter_sync_rx_mode before addr_list_lock is
initialized in SFC driver, from Edward Cree.
9) Fix missing DMA error checking in 3c59x, from Neal Horman.
10) Openvswitch doesn't emit OVS_FLOW_CMD_NEW notifications accidently,
fix from Samuel Gauthier.
11) pch_gbe needs to select NET_PTP_CLASSIFY otherwise we can get a
build error.
12) Fix macvlan regression wherein we stopped emitting
broadcast/multicast frames over software devices. From Nicolas
Dichtel.
13) Fix infiniband bug due to unintended overflow of skb->cb[], from
Eric Dumazet. And add an assertion so this doesn't happen again.
14) dm9000_parse_dt() should return error pointers, not NULL. From
Tobias Klauser.
15) IP tunneling code uses this_cpu_ptr() in preemptible contexts, fix
from Eric Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (87 commits)
net: bcmgenet: call bcmgenet_dma_teardown in bcmgenet_fini_dma
net: bcmgenet: fix TX reclaim accounting for fragments
ipv4: do not use this_cpu_ptr() in preemptible context
dm9000: Return an ERR_PTR() in all error conditions of dm9000_parse_dt()
r8169: fix an if condition
r8152: disable ALDPS
ipoib: validate struct ipoib_cb size
net: sched: shrink struct qdisc_skb_cb to 28 bytes
tg3: Work around HW/FW limitations with vlan encapsulated frames
macvlan: allow to enqueue broadcast pkt on virtual device
pch_gbe: 'select' NET_PTP_CLASSIFY.
scsi: Use 'depends' with LIBFC instead of 'select'.
openvswitch: restore OVS_FLOW_CMD_NEW notifications
genetlink: add function genl_has_listeners()
lib: rhashtable: remove second linux/log2.h inclusion
net: allow macvlans to move to net namespace
3c59x: Fix bad offset spec in skb_frag_dma_map
3c59x: Add dma error checking and recovery
sparc: bpf_jit: fix support for ldx/stx mem and SKF_AD_VLAN_TAG
can: at91_can: add missing prepare and unprepare of the clock
...
|
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git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec
Steffen Klassert says:
====================
pull request (net): ipsec 2014-09-22
We generate a blackhole or queueing route if a packet
matches an IPsec policy but a state can't be resolved.
Here we assume that dst_output() is called to kill
these packets. Unfortunately this assumption is not
true in all cases, so it is possible that these packets
leave the system without the necessary transformations.
This pull request contains two patches to fix this issue:
1) Fix for blackhole routed packets.
2) Fix for queue routed packets.
Both patches are serious stable candidates.
Please pull or let me know if there are problems.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
icsk_rto is a 32bit field, and icsk_backoff can reach 15 by default,
or more if some sysctl (eg tcp_retries2) are changed.
Better use 64bit to perform icsk_rto << icsk_backoff operations
As Joe Perches suggested, add a helper for this.
Yuchung spotted the tcp_v4_err() case.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
RFC2710 (MLDv1), section 3.7. says:
The length of a received MLD message is computed by taking the
IPv6 Payload Length value and subtracting the length of any IPv6
extension headers present between the IPv6 header and the MLD
message. If that length is greater than 24 octets, that indicates
that there are other fields present *beyond* the fields described
above, perhaps belonging to a *future backwards-compatible* version
of MLD. An implementation of the version of MLD specified in this
document *MUST NOT* send an MLD message longer than 24 octets and
MUST ignore anything past the first 24 octets of a received MLD
message.
RFC3810 (MLDv2), section 8.2.1. states for *listeners* regarding
presence of MLDv1 routers:
In order to be compatible with MLDv1 routers, MLDv2 hosts MUST
operate in version 1 compatibility mode. [...] When Host
Compatibility Mode is MLDv2, a host acts using the MLDv2 protocol
on that interface. When Host Compatibility Mode is MLDv1, a host
acts in MLDv1 compatibility mode, using *only* the MLDv1 protocol,
on that interface. [...]
While section 8.3.1. specifies *router* behaviour regarding presence
of MLDv1 routers:
MLDv2 routers may be placed on a network where there is at least
one MLDv1 router. The following requirements apply:
If an MLDv1 router is present on the link, the Querier MUST use
the *lowest* version of MLD present on the network. This must be
administratively assured. Routers that desire to be compatible
with MLDv1 MUST have a configuration option to act in MLDv1 mode;
if an MLDv1 router is present on the link, the system administrator
must explicitly configure all MLDv2 routers to act in MLDv1 mode.
When in MLDv1 mode, the Querier MUST send periodic General Queries
truncated at the Multicast Address field (i.e., 24 bytes long),
and SHOULD also warn about receiving an MLDv2 Query (such warnings
must be rate-limited). The Querier MUST also fill in the Maximum
Response Delay in the Maximum Response Code field, i.e., the
exponential algorithm described in section 5.1.3. is not used. [...]
That means that we should not get queries from different versions of
MLD. When there's a MLDv1 router present, MLDv2 enforces truncation
and MRC == MRD (both fields are overlapping within the 24 octet range).
Section 8.3.2. specifies behaviour in the presence of MLDv1 multicast
address *listeners*:
MLDv2 routers may be placed on a network where there are hosts
that have not yet been upgraded to MLDv2. In order to be compatible
with MLDv1 hosts, MLDv2 routers MUST operate in version 1 compatibility
mode. MLDv2 routers keep a compatibility mode per multicast address
record. The compatibility mode of a multicast address is determined
from the Multicast Address Compatibility Mode variable, which can be
in one of the two following states: MLDv1 or MLDv2.
The Multicast Address Compatibility Mode of a multicast address
record is set to MLDv1 whenever an MLDv1 Multicast Listener Report is
*received* for that multicast address. At the same time, the Older
Version Host Present timer for the multicast address is set to Older
Version Host Present Timeout seconds. The timer is re-set whenever a
new MLDv1 Report is received for that multicast address. If the Older
Version Host Present timer expires, the router switches back to
Multicast Address Compatibility Mode of MLDv2 for that multicast
address. [...]
That means, what can happen is the following scenario, that hosts can
act in MLDv1 compatibility mode when they previously have received an
MLDv1 query (or, simply operate in MLDv1 mode-only); and at the same
time, an MLDv2 router could start up and transmits MLDv2 startup query
messages while being unaware of the current operational mode.
Given RFC2710, section 3.7 we would need to answer to that with an MLDv1
listener report, so that the router according to RFC3810, section 8.3.2.
would receive that and internally switch to MLDv1 compatibility as well.
Right now, I believe since the initial implementation of MLDv2, Linux
hosts would just silently drop such MLDv2 queries instead of replying
with an MLDv1 listener report, which would prevent a MLDv2 router going
into fallback mode (until it receives other MLDv1 queries).
Since the mapping of MRC to MRD in exactly such cases can make use of
the exponential algorithm from 5.1.3, we cannot [strictly speaking] be
aware in MLDv1 of the encoding in MRC, it seems also not mentioned by
the RFC. Since encodings are the same up to 32767, assume in such a
situation this value as a hard upper limit we would clamp. We have asked
one of the RFC authors on that regard, and he mentioned that there seem
not to be any implementations that make use of that exponential algorithm
on startup messages. In any case, this patch fixes this MLD
interoperability issue.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Allow switch drivers to implement per-port Wake-on-LAN getter and
setters.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Add an abstraction layer to suspend/resume switch devices, doing the
following split:
- suspend/resume the slave network devices and their corresponding PHY
devices
- suspend/resume the switch hardware using switch driver callbacks
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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We cannot make struct qdisc_skb_cb bigger without impacting IPoIB,
or increasing skb->cb[] size.
Commit e0f31d849867 ("flow_keys: Record IP layer protocol in
skb_flow_dissect()") broke IPoIB.
Only current offender is sch_choke, and this one do not need an
absolutely precise flow key.
If we store 17 bytes of flow key, its more than enough. (Its the actual
size of flow_keys if it was a packed structure, but we might add new
fields at the end of it later)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: e0f31d849867 ("flow_keys: Record IP layer protocol in skb_flow_dissect()")
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
"create_singlethread_workqueue() is the old interface which is kept
around for backward compatibility - each should be reviewed to
determine whether singlethread usage was to save worker threads or for
ordering guarantee and whether it's depended upon by memory reclaim
path.
While adding NUMA support for unbound workqueues during v3.10, I
forgot to update it breaking the singlethread and ordering properties
on NUMA setups. The breakage was unfortunately rather subtle and went
without being reported until now.
The only missing piece is __WQ_ORDERED flag which makes the unbounded
workqueue use a single backend queue across different NUMA nodes.
It's fixed by making create_singlethread_workqueue() wrap
alloc_ordered_workqueue() so that possible future updates are
inherited automatically"
* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: apply __WQ_ORDERED to create_singlethread_workqueue()
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The recent conversion of saa7134 to vb2 unconvered a poll() bug that
broke the teletext applications alevt and mtt. These applications
expect that calling poll() without having called VIDIOC_STREAMON will
cause poll() to return POLLERR. That did not happen in vb2.
This patch fixes that behavior. It also fixes what should happen when
poll() is called when STREAMON is called but no buffers have been
queued. In that case poll() will also return POLLERR, but only for
capture queues since output queues will always return POLLOUT
anyway in that situation.
This brings the vb2 behavior in line with the old videobuf behavior.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
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The comment for start_streaming that tells the developer with which vb2 state
buffers should be returned to vb2 gave the wrong state. Very confusing.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
Pull staging / IIO fixes from Greg KH:
"Here are some IIO and Staging driver fixes for 3.17-rc6. They are all
pretty simple, and resolve reported issues"
* tag 'staging-3.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
staging: vt6655: buffer overflow in ioctl
iio:magnetometer: bugfix magnetometers gain values
iio: adc: at91: don't use the last converted data register
iio: adc: xilinx-xadc: assign auxiliary channels address correctly
iio: meter: ade7758: Fix indio_dev->trig assignment
iio: inv_mpu6050: Fix indio_dev->trig assignment
iio: gyro: itg3200: Fix indio_dev->trig assignment
iio: st_sensors: Fix indio_dev->trig assignment
iio: hid_sensor_hub: Fix indio_dev->trig assignment
iio: adc: ad_sigma_delta: Fix indio_dev->trig assignment
iio: accel: bma180: Fix indio_dev->trig assignment
iio:trigger: modify return value for iio_trigger_get
iio:inkern: fix overwritten -EPROBE_DEFER in of_iio_channel_get_by_name
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Pull drm fixes from Dave Airlie:
"A bunch of radeon fixes for oops on module unload, and problems with
resetting the dma engine, one nouveau fix for black boxes in rendering
on my mbp retina, one sti fix, and a couple of intel fixes"
* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
drm/nouveau: ltc/gf100-: fix cbc issues on certain boards
drm/bochs: add missing drm_connector_register call
drm/cirrus: add missing drm_connector_register call
drm/radeon: Fix typo 'addr' -> 'entry' in rs400_gart_set_page
drm/nouveau/runpm: fix module unload
drm/radeon/px: fix module unload
vgaswitcheroo: add vga_switcheroo_fini_domain_pm_ops
drm/radeon: don't reset dma on r6xx-evergreen init
drm/radeon: don't reset sdma on CIK init
drm/radeon: don't reset dma on NI/SI init
drm/radeon/dpm: fix resume on mullins
drm/radeon: Disable HDP flush before every CS again for < r600
drm/radeon: delete unused PTE_* defines
drm/i915: Add limited color range readout for HDMI/DP ports on g4x/vlv/chv
drm: sti: do not iterate over the info frame array
drm/i915: Fix SRC_COPY width on 830/845g
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git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus
Jonathan writes:
First round of IIO fixes for the 3.17 cycle.
* Fix an overwritten error return that can prevent deferred probing when
using of_iio_channel_get_by_name
* A series that deals with an incorrect reference count when the default
trigger is set within the main probe routine for a driver. Can result
in a double free if the trigger is changed.
* Fix a buglet with xilinx-xadc concerning setup of the address for an
aux channel.
* At91 adc driver could sometimes get a touchscreen reading rather than
the intended adc channel. This is fixed by using the channel data register
instead.
* Fix some ST magnetometer gain values that differ in production parts from
the prerelease ones used for driver development.
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This feature is intended for archs having cache line larger then 64B.
Since our CQE/EQEs are generally 64B in those systems, HW will write
twice to the same cache line consecutively, causing pipe locks due to
he hazard prevention mechanism. For elements in a cyclic buffer, writes
are consecutive, so entries smaller than a cache line should be
avoided, especially if they are written at a high rate.
Reduce consecutive writes to same cache line in CQs/EQs, by allowing the
driver to increase the distance between entries so that each will reside
in a different cache line. Until the introduction of this feature, there
were two types of CQE/EQE:
1. 32B stride and context in the [0-31] segment
2. 64B stride and context in the [32-63] segment
This feature introduces two additional types:
3. 128B stride and context in the [0-31] segment (128B cache line)
4. 256B stride and context in the [0-31] segment (256B cache line)
Modify the mlx4_core driver to query the device for the CQE/EQE cache
line stride capability and to enable that capability when the host
cache line size is larger than 64 bytes (supported cache lines are
128B and 256B).
The mlx4 IB driver and libmlx4 need not be aware of this change. The PF
context behaviour is changed to require this change in VF drivers
running on such archs.
Signed-off-by: Ido Shamay <idos@mellanox.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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