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  1. 05 Oct, 2015 14 commits
    • Arnd Bergmann's avatar
      mwifiex: avoid gettimeofday in ba_threshold setting · 52f4f918
      Arnd Bergmann authored 
      mwifiex_get_random_ba_threshold() uses a complex homegrown implementation
to generate a pseudo-random number from the current time as returned
from do_gettimeofday().

This currently requires two 32-bit divisions plus a couple of other
computations that are eventually discarded as only eight bits of
the microsecond portion are used at all.

We could replace this with a call to get_random_bytes(), but that
might drain the entropy pool too fast if this is called for each
packet.

Instead, this patch converts it to use ktime_get_ns(), which is a
bit faster than do_gettimeofday(), and then uses a similar algorithm
as before, but in a way that takes both the nanosecond and second
portion into account for slightly-more-but-still-not-very-random
pseudorandom number.
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Cc: Nishant Sarmukadam <nishants@marvell.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      52f4f918
    • Arnd Bergmann's avatar
      mwifiex: use ktime_get_real for timestamping · e253fb74
      Arnd Bergmann authored 
      The mwifiex_11n_aggregate_pkt() function creates a ktime_t from
a timeval returned by do_gettimeofday, which is slow and causes
an overflow in 2038 on 32-bit architectures.

This solves both problems by using the appropriate ktime_get_real()
function.
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Cc: Nishant Sarmukadam <nishants@marvell.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e253fb74
    • Arnd Bergmann's avatar
      net: igb: avoid using timespec · 40c9b079
      Arnd Bergmann authored 
      We want to deprecate the use of 'struct timespec' on 32-bit
architectures, as it is will overflow in 2038. The igb
driver uses it to read the current time, and can simply
be changed to use ktime_get_real_ts64() instead.

Because of hardware limitations, there is still an overflow
in year 2106, which we cannot really avoid, but this documents
the overflow.
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: intel-wired-lan@lists.osuosl.org
Reviewed-by: default avatarRichard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      40c9b079
    • Arnd Bergmann's avatar
      net: stmmac: avoid using timespec · 0a624155
      Arnd Bergmann authored 
      We want to deprecate the use of 'struct timespec' on 32-bit
architectures, as it is will overflow in 2038. The stmmac
driver uses it to read the current time, and can simply
be changed to use ktime_get_real_ts64() instead.

Because of hardware limitations, there is still an overflow
in year 2106, which we cannot really avoid, but this documents
the overflow.
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Acked-by: default avatarRichard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0a624155
    • Arnd Bergmann's avatar
      net: fec: avoid timespec use · be7ccdc3
      Arnd Bergmann authored 
      The fec_ptp_enable_pps uses an open-coded implementation of ns_to_timespec,
which will be removed eventually as it is not y2038-safe on 32-bit
architectures. Two more instances of the same code in this file were
already converted to use the safe ns_to_timespec64 in commit 6630514f
("ptp: fec: use helpers for converting ns to timespec"), this changes
the last one as well.

The seconds portion here is actually unused and we could just remove the
timespec variable, but using ns_to_timespec64 can still be better as the
implementation can be hand-optimized in the future.
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Fugang Duan <b38611@freescale.com>
Cc: Luwei Zhou <b45643@freescale.com>
Cc: Frank Li <Frank.Li@freescale.com>
Acked-by: default avatarRichard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      be7ccdc3
    • David S. Miller's avatar
      Merge branch 'ipv4-multipath-hash' · 07355737
      David S. Miller authored 
      Peter Nørlund says:

====================
ipv4: Hash-based multipath routing

When the routing cache was removed in 3.6, the IPv4 multipath algorithm changed
from more or less being destination-based into being quasi-random per-packet
scheduling. This increases the risk of out-of-order packets and makes it
impossible to use multipath together with anycast services.

This patch series replaces the old implementation with flow-based load
balancing based on a hash over the source and destination addresses.

Distribution of the hash is done with thresholds as described in RFC 2992.
This reduces the disruption when a path is added/remove when having more than
two paths.

To futher the chance of successful usage in conjuction with anycast, ICMP
error packets are hashed over the inner IP addresses. This ensures that PMTU
will work together with anycast or load-balancers such as IPVS.

Port numbers are not considered since fragments could cause problems with
anycast and IPVS. Relying on the DF-flag for TCP packets is also insufficient,
since ICMP inspection effectively extracts information from the opposite
flow which might have a different state of the DF-flag. This is also why the
RSS hash is not used. These are typically based on the NDIS RSS spec which
mandates TCP support.

Measurements of the additional overhead of a two-path multipath
(p_mkroute_input excl. __mkroute_input) on a Xeon X3550 (4 cores, 2.66GHz):

Original per-packet: ~394 cycles/packet
L3 hash:              ~76 cycles/packet

Changes in v5:
- Fixed compilation error

Changes in v4:
- Functions take hash directly instead of func ptr
- Added inline hash function
- Added dummy macros to minimize ifdefs
- Use upper 31 bits of hash instead of lower

Changes in v3:
- Multipath algorithm is no longer configurable (always L3)
- Added random seed to hash
- Moved ICMP inspection to isolated function
- Ignore source quench packets (deprecated as per RFC 6633)

Changes in v2:
- Replaced 8-bit xor hash with 31-bit jenkins hash
- Don't scale weights (since 31-bit)
- Avoided unnecesary renaming of variables
- Rely on DF-bit instead of fragment offset when checking for fragmentation
- upper_bound is now inclusive to avoid overflow
- Use a callback to postpone extracting flow information until necessary
- Skipped ICMP inspection entirely with L4 hashing
- Handle newly added sysctl ignore_routes_with_linkdown
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      07355737
    • Peter Nørlund's avatar
      ipv4: ICMP packet inspection for multipath · 79a13159
      Peter Nørlund authored 
      ICMP packets are inspected to let them route together with the flow they
belong to, minimizing the chance that a problematic path will affect flows
on other paths, and so that anycast environments can work with ECMP.
Signed-off-by: default avatarPeter Nørlund <pch@ordbogen.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      79a13159
    • Peter Nørlund's avatar
      ipv4: L3 hash-based multipath · 0e884c78
      Peter Nørlund authored 
      Replaces the per-packet multipath with a hash-based multipath using
source and destination address.
Signed-off-by: default avatarPeter Nørlund <pch@ordbogen.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0e884c78
    • David S. Miller's avatar
      Merge branch 'tcp-listener-fixes-and-improvement' · 2472186f
      David S. Miller authored 
      Eric Dumazet says:

====================
tcp: lockless listener fixes and improvement

This fixes issues with TCP FastOpen vs lockless listeners,
and SYNACK being attached to request sockets.

Then, last patch brings performance improvement for
syncookies generation and validation.

Tested under a 4.3 Mpps SYNFLOOD attack, new perf profile looks
like :
    12.11%  [kernel]  [k] sha_transform
     5.83%  [kernel]  [k] tcp_conn_request
     4.59%  [kernel]  [k] __inet_lookup_listener
     4.11%  [kernel]  [k] ipt_do_table
     3.91%  [kernel]  [k] tcp_make_synack
     3.05%  [kernel]  [k] fib_table_lookup
     2.74%  [kernel]  [k] sock_wfree
     2.66%  [kernel]  [k] memcpy_erms
     2.12%  [kernel]  [k] tcp_v4_rcv
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2472186f
    • Eric Dumazet's avatar
      tcp: avoid two atomic ops for syncookies · a1a5344d
      Eric Dumazet authored 
      inet_reqsk_alloc() is used to allocate a temporary request
in order to generate a SYNACK with a cookie. Then later,
syncookie validation also uses a temporary request.

These paths already took a reference on listener refcount,
we can avoid a couple of atomic operations.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a1a5344d
    • Eric Dumazet's avatar
      net: use sk_fullsock() in __netdev_pick_tx() · 004a5d01
      Eric Dumazet authored 
      SYN_RECV & TIMEWAIT sockets are not full blown, they do not have a
sk_dst_cache pointer.

Fixes: ca6fb065 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      004a5d01
    • Eric Dumazet's avatar
      ipv6: inet6_sk() should use sk_fullsock() · e7eadb4d
      Eric Dumazet authored 
      SYN_RECV & TIMEWAIT sockets are not full blown, they do not have a pinet6
pointer.

Fixes: ca6fb065 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e7eadb4d
    • Eric Dumazet's avatar
      inet: ip_skb_dst_mtu() should use sk_fullsock() · caf3f267
      Eric Dumazet authored 
      SYN_RECV & TIMEWAIT sockets are not full blown,
do not even try to call ip_sk_use_pmtu() on them.

Fixes: ca6fb065 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      caf3f267
    • Eric Dumazet's avatar
      tcp: fix fastopen races vs lockless listener · 7656d842
      Eric Dumazet authored 
      There are multiple races that need fixes :

1) skb_get() + queue skb + kfree_skb() is racy

An accept() can be done on another cpu, data consumed immediately.
tcp_recvmsg() uses __kfree_skb() as it is assumed all skb found in
socket receive queue are private.

Then the kfree_skb() in tcp_rcv_state_process() uses an already freed skb

2) tcp_reqsk_record_syn() needs to be done before tcp_try_fastopen()
for the same reasons.

3) We want to send the SYNACK before queueing child into accept queue,
otherwise we might reintroduce the ooo issue fixed in
commit 7c85af88 ("tcp: avoid reorders for TFO passive connections")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      7656d842
  3. 04 Oct, 2015 26 commits
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