Commit Graph

41667 Commits

Author SHA1 Message Date
John Fastabend
d033d526a4 ixgbe: DCB, implement 802.1Qaz routines
Implements 802.1Qaz support for ixgbe driver. Additionally,
this adds IEEE_8021QAZ_TSA_{} defines to dcbnl.h this is to
avoid having to use cryptic numeric codes for the TSA type.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2011-02-11 08:47:15 -08:00
David S. Miller
6431cbc25f inet: Create a mechanism for upward inetpeer propagation into routes.
If we didn't have a routing cache, we would not be able to properly
propagate certain kinds of dynamic path attributes, for example
PMTU information and redirects.

The reason is that if we didn't have a routing cache, then there would
be no way to lookup all of the active cached routes hanging off of
sockets, tunnels, IPSEC bundles, etc.

Consider the case where we created a cached route, but no inetpeer
entry existed and also we were not asked to pre-COW the route metrics
and therefore did not force the creation a new inetpeer entry.

If we later get a PMTU message, or a redirect, and store this
information in a new inetpeer entry, there is no way to teach that
cached route about the newly existing inetpeer entry.

The facilities implemented here handle this problem.

First we create a generation ID.  When we create a cached route of any
kind, we remember the generation ID at the time of attachment.  Any
time we force-create an inetpeer entry in response to new path
information, we bump that generation ID.

The dst_ops->check() callback is where the knowledge of this event
is propagated.  If the global generation ID does not equal the one
stored in the cached route, and the cached route has not attached
to an inetpeer yet, we look it up and attach if one is found.  Now
that we've updated the cached route's information, we update the
route's generation ID too.

This clears the way for implementing PMTU and redirects directly in
the inetpeer cache.  There is absolutely no need to consult cached
route information in order to maintain this information.

At this point nothing bumps the inetpeer genids, that comes in the
later changes which handle PMTUs and redirects using inetpeers.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-10 13:33:41 -08:00
David S. Miller
ddd4aa424b inetpeer: Add redirect and PMTU discovery cached info.
Validity of the cached PMTU information is indicated by it's
expiration value being non-zero, just as per dst->expires.

The scheme we will use is that we will remember the pre-ICMP value
held in the metrics or route entry, and then at expiration time
we will restore that value.

In this way PMTU expiration does not kill off the cached route as is
done currently.

Redirect information is permanent, or at least until another redirect
is received.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-10 13:29:30 -08:00
David S. Miller
7a71ed899e inetpeer: Abstract address representation further.
Future changes will add caching information, and some of
these new elements will be addresses.

Since the family is implicit via the ->daddr.family member,
replicating the family in ever address we store is entirely
redundant.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-10 13:22:28 -08:00
David S. Miller
263fb5b1bf Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/e1000e/netdev.c
2011-02-08 17:19:01 -08:00
David S. Miller
8d13a2a9fb net: Kill NETEVENT_PMTU_UPDATE.
Nobody actually does anything in response to the event,
so just kill it off.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-08 16:17:55 -08:00
David S. Miller
e7b66bdc02 net: Remove bogus barrier() in dst_allfrag().
I simply missed this one when modifying the other dst
metric interfaces earlier.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-08 15:33:22 -08:00
Nicolas Dichtel
fa9921e46f ipsec: allow to align IPv4 AH on 32 bits
The Linux IPv4 AH stack aligns the AH header on a 64 bit boundary
(like in IPv6). This is not RFC compliant (see RFC4302, Section
3.3.3.2.1), it should be aligned on 32 bits.

For most of the authentication algorithms, the ICV size is 96 bits.
The AH header alignment on 32 or 64 bits gives the same results.

However for SHA-256-128 for instance, the wrong 64 bit alignment results
in adding useless padding in IPv4 AH, which is forbidden by the RFC.

To avoid breaking backward compatibility, we use a new flag
(XFRM_STATE_ALIGN4) do change original behavior.

Initial patch from Dang Hongwu <hongwu.dang@6wind.com> and
Christophe Gouault <christophe.gouault@6wind.com>.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-08 14:00:40 -08:00
Alexey Orishko
3a9dda7602 CDC NCM errata updates for cdc.h
Changes are based on the following documents:
- CDC NCM errata:
http://www.usb.org/developers/devclass_docs/NCM10_012011.zip
- CDC and WMC errata link:
http://www.usb.org/developers/devclass_docs/CDC1.2_WMC1.1_012011.zip

Signed-off-by: Alexey Orishko <alexey.orishko@stericsson.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-08 13:54:42 -08:00
David S. Miller
c0c84ef5c1 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 2011-02-08 13:52:31 -08:00
David S. Miller
7eb38527c4 tcp: Add reference to initial CWND ietf draft.
Suggested by Alexander Zimmermann

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-05 18:13:45 -08:00
David S. Miller
92d8682926 inetpeer: Move ICMP rate limiting state into inet_peer entries.
Like metrics, the ICMP rate limiting bits are cached state about
a destination.  So move it into the inet_peer entries.

If an inet_peer cannot be bound (the reason is memory allocation
failure or similar), the policy is to allow.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-04 15:59:53 -08:00
David S. Miller
bd4a6974cc Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2011-02-04 14:28:58 -08:00
Julia Lawall
38db9e1db1 include/net/genetlink.h: Allow genlmsg_cancel to accept a NULL argument
nlmsg_cancel can accept NULL as its second argument, so for similarity,
this patch extends genlmsg_cancel to be able to accept a NULL second
argument as well.

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-03 20:47:08 -08:00
David S. Miller
e2d57766e6 net: Provide compat support for SIOCGETMIFCNT_IN6 and SIOCGETSGCNT_IN6.
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-03 18:05:29 -08:00
Jouni Malinen
681d119047 mac80211: Add testing functionality for TKIP
TKIP countermeasures depend on devices being able to detect Michael
MIC failures on received frames and for stations to report errors to
the AP. In order to test that behavior, it is useful to be able to
send out TKIP frames with incorrect Michael MIC. This testing behavior
has minimal effect on the TX path, so it can be added to mac80211 for
convenient use.

The interface for using this functionality is a file in mac80211
netdev debugfs (tkip_mic_test). Writing a MAC address to the file
makes mac80211 generate a dummy data frame that will be sent out using
invalid Michael MIC value. In AP mode, the address needs to be for one
of the associated stations or ff:ff:ff:ff:ff:ff to use a broadcast
frame. In station mode, the address can be anything, e.g., the current
BSSID. It should be noted that this functionality works correctly only
when associated and using TKIP.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-02-03 16:45:29 -05:00
Arik Nemtsov
d057e5a381 mac80211: add HW flag for disabling auto link-PS in AP mode
When operating in AP mode the wl1271 hardware filters out null-data
packets as well as management packets. This makes it impossible for
mac80211 to monitor the PS mode by using the PM bit of incoming frames.

Implement a HW flag to indicate that mac80211 should ignore the PM bit.
In addition, expose ieee80211_sta_ps_transition() to make low-level
drivers capable of controlling PS-mode.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-02-03 16:44:44 -05:00
David S. Miller
fd95240568 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 2011-02-03 13:06:43 -08:00
stephen hemminger
45e144339a sched: CHOKe flow scheduler
CHOKe ("CHOose and Kill" or "CHOose and Keep") is an alternative
packet scheduler based on the Random Exponential Drop (RED) algorithm.

The core idea is:
  For every packet arrival:
  	Calculate Qave
	if (Qave < minth)
	     Queue the new packet
	else
	     Select randomly a packet from the queue
	     if (both packets from same flow)
	     then Drop both the packets
	     else if (Qave > maxth)
	          Drop packet
	     else
	       	  Admit packet with proability p (same as RED)

See also:
  Rong Pan, Balaji Prabhakar, Konstantinos Psounis, "CHOKe: a stateless active
   queue management scheme for approximating fair bandwidth allocation",
  Proceeding of INFOCOM'2000, March 2000.

Help from:
     Eric Dumazet <eric.dumazet@gmail.com>
     Patrick McHardy <kaber@trash.net>

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-02 20:52:42 -08:00
David S. Miller
442b9635c5 tcp: Increase the initial congestion window to 10.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Nandita Dukkipati <nanditad@google.com>
2011-02-02 20:48:47 -08:00
David S. Miller
0bc0be7f20 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/kaber/nf-2.6 2011-02-02 15:52:23 -08:00
David S. Miller
8fe73503fa Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/kaber/nf-next-2.6 2011-02-02 15:24:48 -08:00
Patrick McHardy
9291747f11 netfilter: xtables: add device group match
Add a new 'devgroup' match to match on the device group of the
incoming and outgoing network device of a packet.

Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-03 00:05:43 +01:00
Patrick McHardy
724bab476b netfilter: ipset: fix linking with CONFIG_IPV6=n
Add a dummy ip_set_get_ip6_port function that unconditionally
returns false for CONFIG_IPV6=n and convert the real function
to ipv6_skip_exthdr() to avoid pulling in the ip6_tables module
when loading ipset.

Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-02 23:50:01 +01:00
David S. Miller
5348ba85a0 ipv4: Update some fib_hash centric interface names.
fib_hash_init() --> fib_trie_init()
fib_hash_table() --> fib_trie_table()

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-01 15:35:25 -08:00
Patrick McHardy
e3e241b276 netfilter: ipset: install ipset related header files
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 18:52:42 +01:00
Simon Horman
a13676476e IPVS: Remove unused variables
These variables are unused as a result of the recent netns work.

Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Hans Schillstrom <hans@schillstrom.com>
Tested-by: Hans Schillstrom <hans@schillstrom.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 18:27:51 +01:00
Pablo Neira Ayuso
3db7e93d33 netfilter: ecache: always set events bits, filter them later
For the following rule:

iptables -I PREROUTING -t raw -j CT --ctevents assured

The event delivered looks like the following:

 [UPDATE] tcp      6 src=192.168.0.2 dst=192.168.1.2 sport=37041 dport=80 src=192.168.1.2 dst=192.168.1.100 sport=80 dport=37041 [ASSURED]

Note that the TCP protocol state is not included. For that reason
the CT event filtering is not very useful for conntrackd.

To resolve this issue, instead of conditionally setting the CT events
bits based on the ctmask, we always set them and perform the filtering
in the late stage, just before the delivery.

Thus, the event delivered looks like the following:

 [UPDATE] tcp      6 432000 ESTABLISHED src=192.168.0.2 dst=192.168.1.2 sport=37041 dport=80 src=192.168.1.2 dst=192.168.1.100 sport=80 dport=37041 [ASSURED]

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 16:06:30 +01:00
Jozsef Kadlecsik
d956798d82 netfilter: xtables: "set" match and "SET" target support
The patch adds the combined module of the "SET" target and "set" match
to netfilter. Both the previous and the current revisions are supported.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 15:56:00 +01:00
Jozsef Kadlecsik
f830837f0e netfilter: ipset: list:set set type support
The module implements the list:set type support in two flavours:
without and with timeout. The sets has two sides: for the userspace,
they store the names of other (non list:set type of) sets: one can add,
delete and test set names. For the kernel, it forms an ordered union of
the member sets: the members sets are tried in order when elements are
added, deleted and tested and the process stops at the first success.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 15:54:59 +01:00
Jozsef Kadlecsik
6c02788969 netfilter: ipset: hash:ip set type support
The module implements the hash:ip type support in four flavours:
for IPv4 or IPv6, both without and with timeout support.

All the hash types are based on the "array hash" or ahash structure
and functions as a good compromise between minimal memory footprint
and speed. The hashing uses arrays to resolve clashes. The hash table
is resized (doubled) when searching becomes too long. Resizing can be
triggered by userspace add commands only and those are serialized by
the nfnl mutex. During resizing the set is read-locked, so the only
possible concurrent operations are the kernel side readers. Those are
protected by RCU locking.

Because of the four flavours and the other hash types, the functions
are implemented in general forms in the ip_set_ahash.h header file
and the real functions are generated before compiling by macro expansion.
Thus the dereferencing of low-level functions and void pointer arguments
could be avoided: the low-level functions are inlined, the function
arguments are pointers of type-specific structures.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 15:38:36 +01:00
Jozsef Kadlecsik
72205fc68b netfilter: ipset: bitmap:ip set type support
The module implements the bitmap:ip set type in two flavours, without
and with timeout support. In this kind of set one can store IPv4
addresses (or network addresses) from a given range.

In order not to waste memory, the timeout version does not rely on
the kernel timer for every element to be timed out but on garbage
collection. All set types use this mechanism.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 15:33:17 +01:00
Jozsef Kadlecsik
a7b4f989a6 netfilter: ipset: IP set core support
The patch adds the IP set core support to the kernel.

The IP set core implements a netlink (nfnetlink) based protocol by which
one can create, destroy, flush, rename, swap, list, save, restore sets,
and add, delete, test elements from userspace. For simplicity (and backward
compatibilty and for not to force ip(6)tables to be linked with a netlink
library) reasons a small getsockopt-based protocol is also kept in order
to communicate with the ip(6)tables match and target.

The netlink protocol passes all u16, etc values in network order with
NLA_F_NET_BYTEORDER flag. The protocol enforces the proper use of the
NLA_F_NESTED and NLA_F_NET_BYTEORDER flags.

For other kernel subsystems (netfilter match and target) the API contains
the functions to add, delete and test elements in sets and the required calls
to get/put refereces to the sets before those operations can be performed.

The set types (which are implemented in independent modules) are stored
in a simple RCU protected list. A set type may have variants: for example
without timeout or with timeout support, for IPv4 or for IPv6. The sets
(i.e. the pointers to the sets) are stored in an array. The sets are
identified by their index in the array, which makes possible easy and
fast swapping of sets. The array is protected indirectly by the nfnl
mutex from nfnetlink. The content of the sets are protected by the rwlock
of the set.

There are functional differences between the add/del/test functions
for the kernel and userspace:

- kernel add/del/test: works on the current packet (i.e. one element)
- kernel test: may trigger an "add" operation  in order to fill
  out unspecified parts of the element from the packet (like MAC address)
- userspace add/del: works on the netlink message and thus possibly
  on multiple elements from the IPSET_ATTR_ADT container attribute.
- userspace add: may trigger resizing of a set

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 15:28:35 +01:00
Jozsef Kadlecsik
f703651ef8 netfilter: NFNL_SUBSYS_IPSET id and NLA_PUT_NET* macros
The patch adds the NFNL_SUBSYS_IPSET id and NLA_PUT_NET* macros to the
vanilla kernel.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 15:20:14 +01:00
David S. Miller
0c838ff1ad ipv4: Consolidate all default route selection implementations.
Both fib_trie and fib_hash have a local implementation of
fib_table_select_default().  This is completely unnecessary
code duplication.

Since we now remember the fib_table and the head of the fib
alias list of the default route, we can implement one single
generic version of this routine.

Looking at the fib_hash implementation you may get the impression
that it's possible for there to be multiple top-level routes in
the table for the default route.  The truth is, it isn't, the
insert code will only allow one entry to exist in the zero
prefix hash table, because all keys evaluate to zero and all
keys in a hash table must be unique.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-31 16:16:50 -08:00
David S. Miller
5b4704419c ipv4: Remember FIB alias list head and table in lookup results.
This will be used later to implement fib_select_default() in a
completely generic manner, instead of the current situation where the
default route is re-looked up in the TRIE/HASH table and then the
available aliases are analyzed.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-31 16:10:03 -08:00
David S. Miller
5403c8a295 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2011-01-31 13:13:24 -08:00
Eric W. Biederman
709b46e8d9 net: Add compat ioctl support for the ipv4 multicast ioctl SIOCGETSGCNT
SIOCGETSGCNT is not a unique ioctl value as it it maps tio SIOCPROTOPRIVATE +1,
which unfortunately means the existing infrastructure for compat networking
ioctls is insufficient.  A trivial compact ioctl implementation would conflict
with:

SIOCAX25ADDUID
SIOCAIPXPRISLT
SIOCGETSGCNT_IN6
SIOCGETSGCNT
SIOCRSSCAUSE
SIOCX25SSUBSCRIP
SIOCX25SDTEFACILITIES

To make this work I have updated the compat_ioctl decode path to mirror the
the normal ioctl decode path.  I have added an ipv4 inet_compat_ioctl function
so that I can have ipv4 specific compat ioctls.   I have added a compat_ioctl
function into struct proto so I can break out ioctls by which kind of ip socket
I am using.  I have added a compat_raw_ioctl function because SIOCGETSGCNT only
works on raw sockets.  I have added a ipmr_compat_ioctl that mirrors the normal
ipmr_ioctl.

This was necessary because unfortunately the struct layout for the SIOCGETSGCNT
has unsigned longs in it so changes between 32bit and 64bit kernels.

This change was sufficient to run a 32bit ip multicast routing daemon on a
64bit kernel.

Reported-by: Bill Fenner <fenner@aristanetworks.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-30 01:14:38 -08:00
sjur.brandeland@stericsson.com
52fe7c9cc1 caif: bugfix - add caif headers for userspace usage.
Add caif_socket.h and if_caif.h to the kernel header files
exported for use by userspace.

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-30 01:14:14 -08:00
David S. Miller
725d1e1b45 ipv4: Attach FIB info to dst_default_metrics when possible
If there are no explicit metrics attached to a route, hook
fi->fib_info up to dst_default_metrics.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-28 14:05:05 -08:00
David S. Miller
9c150e82ac ipv4: Allocate fib metrics dynamically.
This is the initial gateway towards super-sharing metrics
if they are all set to zero for a route.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-28 14:01:25 -08:00
John W. Linville
3e11210d46 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6
Conflicts:
	drivers/net/wireless/ath/ath9k/init.c
2011-01-28 16:23:14 -05:00
Johannes Berg
6d744bacee mac80211: add MCS information to radiotap
This adds the MCS information we currently get
from the drivers into radiotap.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-01-28 15:44:29 -05:00
David S. Miller
a4daad6b09 net: Pre-COW metrics for TCP.
TCP is going to record metrics for the connection,
so pre-COW the route metrics at route cache entry
creation time.

This avoids several atomic operations that have to
occur if we COW the metrics after the entry reaches
global visibility.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-27 22:01:53 -08:00
David S. Miller
8571a19c4a Merge branch 'master' of ssh://master.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 2011-01-27 16:00:37 -08:00
Eric Dumazet
ccf434380d net: fix dev_seq_next()
Commit c6d14c8456 (net: Introduce for_each_netdev_rcu() iterator)
added a race in dev_seq_next().

The rcu_dereference() call should be done _before_ testing the end of
list, or we might return a wrong net_device if a concurrent thread
changes net_device list under us.

Note : discovered thanks to a sparse warning :

net/core/dev.c:3919:9: error: incompatible types in comparison expression
(different address spaces)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-27 15:02:56 -08:00
David S. Miller
144001bddc inetpeer: Mark metrics as "new" in fresh inetpeer entries.
Set the RTAX_LOCKED metric to INETPEER_METRICS_NEW (basically,
all ones) on fresh inetpeer entries.

This way code can determine if default metrics have been loaded
in from a routing table entry already.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-27 13:52:16 -08:00
David S. Miller
606598237c inetpeer: Add metrics storage to inetpeer entries.
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-27 13:48:26 -08:00
David S. Miller
62fa8a846d net: Implement read-only protection and COW'ing of metrics.
Routing metrics are now copy-on-write.

Initially a route entry points it's metrics at a read-only location.
If a routing table entry exists, it will point there.  Else it will
point at the all zero metric place-holder called 'dst_default_metrics'.

The writeability state of the metrics is stored in the low bits of the
metrics pointer, we have two bits left to spare if we want to store
more states.

For the initial implementation, COW is implemented simply via kmalloc.
However future enhancements will change this to place the writable
metrics somewhere else, in order to increase sharing.  Very likely
this "somewhere else" will be the inetpeer cache.

Note also that this means that metrics updates may transiently fail
if we cannot COW the metrics successfully.

But even by itself, this patch should decrease memory usage and
increase cache locality especially for routing workloads.  In those
cases the read-only metric copies stay in place and never get written
to.

TCP workloads where metrics get updated, and those rare cases where
PMTU triggers occur, will take a very slight performance hit.  But
that hit will be alleviated when the long-term writable metrics
move to a more sharable location.

Since the metrics storage went from a u32 array of RTAX_MAX entries to
what is essentially a pointer, some retooling of the dst_entry layout
was necessary.

Most importantly, we need to preserve the alignment of the reference
count so that it doesn't share cache lines with the read-mostly state,
as per Eric Dumazet's alignment assertion checks.

The only non-trivial bit here is the move of the 'flags' member into
the writeable cacheline.  This is OK since we are always accessing the
flags around the same moment when we made a modification to the
reference count.

Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-26 20:51:05 -08:00
David S. Miller
b4e69ac670 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2011-01-26 13:49:30 -08:00