This patch kills a redundant rcu_dereference on fa->fa_info in fib_trie.c.
As this dereference directly follows a list_for_each_entry_rcu line, we
have already taken a read barrier with respect to getting an entry from
the list.

This read barrier guarantees that all values read out of fa are valid.
In particular, the contents of structure pointed to by fa->fa_info is
initialised before fa->fa_info is actually set (see fn_trie_insert);
the setting of fa->fa_info itself is further separated with a write
barrier from the insertion of fa into the list.

Therefore by taking a read barrier after obtaining fa from the list
(which is given by list_for_each_entry_rcu), we can be sure that
fa->fa_info contains a valid pointer, as well as the fact that the
data pointed to by fa->fa_info is itself valid.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Acked-by: NPaul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

The patch below introduces special thresholds to keep root node in the trie 
large. This gives a flatter tree at the cost of a modest memory increase.
Overall it seems to be gain and this was also proposed by one the authors 
of the paper in recent a seminar.

Main table after loading 123 k routes.

	Aver depth:     3.30
	Max depth:      9
        Root-node size  12 bits
        Total size: 4044  kB

With the patch:
	Aver depth:     2.78
	Max depth:      8
        Root-node size  15 bits
        Total size: 4150  kB

An increase of 8-10% was seen in forwading performance for an rDoS attack. 
Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Cleanup the printk's in fib_trie:
	* Convert a couple of places in the dump code to BUG_ON
	* Put log level's on each message
The version message really needed the message since it leaks out
on the pretty Fedora bootup.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Acked-by: Robert Olsson <Robert.Olsson@data.slu.se>,
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* This patch is from Paul McKenney's RCU reviewing. 
Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* Prints the route tnode and set the stats level deepth as before.
Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Create one iterator for walking over FIB trie, and use it
for all the /proc functions. Add a /proc/net/route
output for backwards compatibility with old applications.

Make initialization of fib_trie same as fib_hash so no #ifdef
is needed in af_inet.c

Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=5209Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch puts mostly read only data in the right section
(read_mostly), to help sharing of these data between CPUS without
memory ping pongs.

On one of my production machine, tcp_statistics was sitting in a
heavily modified cache line, so *every* SNMP update had to force a
reload.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* Removes RW-lock
* Proteced read functions uses
  rcu_dereference proteced with rcu_read_lock()
* writing of procted pointer w. rcu_assigen_pointer
* Insert/Replace atomic list_replace_rcu
* A BUG_ON condition removed.in trie_rebalance

With help from Paul E. McKenney.
Signed-off-by: NRobert Olsson <Robert.Olsson@data.slu.se>
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a redo of earlier cleanup stuff:
	* replace DBG() macro with pr_debug()
	* get rid of duplicate extern's that are already in fib_lookup.h
	* use BUG_ON and WARN_ON
	* don't use BUG checks for null pointers where next statement would
	  get a fault anyway
	* remove debug printout when rebalance causes deep tree
	* remove trailing blanks
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use const where possible and get rid of EXTRACT() macro
that was never used.
Signed-off-by: NStephen Hemmigner <shemminger@osdl.org>
Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Below is a patch that cleans up some of this, supposedly without
changing any behaviour:

* Whitespace cleanups
* Introduce DBG()
* BUG_ON() instead of if () { BUG(); }
* Remove some of the deep nesting to make the code flow more
  comprehensible
* Some mask operations were simplified
Signed-off-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a semantic match occurs either success, not found or an error
(for matching unreachable routes/blackholes) is returned. fib_trie
ignores the errors and looks for a different matching route. Treat
results other than "no match" as success and end lookup.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Below a patch to preallocate memory when doing resize of trie (inflate halve)
If preallocations fails it just skips the resize of this tnode for this time.

The oops we got when killing bgpd (with full routing) is now gone. 
Patrick memory patch is also used.
Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Inflating a node a couple of times makes it exceed the 128k kmalloc limit.
Use __get_free_pages for allocations > PAGE_SIZE, as in fib_hash.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Acked-by: NRobert Olsson <Robert.Olsson@data.slu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This should help up the insertion... but the resize is more crucial.
and complex and needs some thinking. 
Signed-off-by: NRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NRobert Olsson <Robert.Olsson@data.slu.se>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>