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authorEric Dumazet <dada1@cosmosbay.com>2005-07-05 15:00:32 -0700
committerDavid S. Miller <davem@davemloft.net>2005-07-05 15:00:32 -0700
commitbb1d23b02657f494dff295f6cdd1f29df30fa61e (patch)
tree59c170cb94d2f65a0717ea67e169b3e2e22be11e
parent424c4b70cc4ff3930ee36a2ef7b204e4d704fd26 (diff)
downloadlinux-stericsson-bb1d23b02657f494dff295f6cdd1f29df30fa61e.tar.gz
[IPV4]: Bug fix in rt_check_expire()
- rt_check_expire() fixes (an overflow occured if size of the hash was >= 65536) reminder of the bugfix: The rt_check_expire() has a serious problem on machines with large route caches, and a standard HZ value of 1000. With default values, ie ip_rt_gc_interval = 60*HZ = 60000 ; the loop count : for (t = ip_rt_gc_interval << rt_hash_log; t >= 0; overflows (t is a 31 bit value) as soon rt_hash_log is >= 16 (65536 slots in route cache hash table). In this case, rt_check_expire() does nothing at all Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/route.c21
1 files changed, 14 insertions, 7 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 9fcbb1b0a8d6..726ea5e8180a 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -54,7 +54,7 @@
* Marc Boucher : routing by fwmark
* Robert Olsson : Added rt_cache statistics
* Arnaldo C. Melo : Convert proc stuff to seq_file
- * Eric Dumazet : hashed spinlocks
+ * Eric Dumazet : hashed spinlocks and rt_check_expire() fixes.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -606,18 +606,25 @@ static struct rtable **rt_remove_balanced_route(struct rtable **chain_head,
/* This runs via a timer and thus is always in BH context. */
static void rt_check_expire(unsigned long dummy)
{
- static int rover;
- int i = rover, t;
+ static unsigned int rover;
+ unsigned int i = rover, goal;
struct rtable *rth, **rthp;
unsigned long now = jiffies;
-
- for (t = ip_rt_gc_interval << rt_hash_log; t >= 0;
- t -= ip_rt_gc_timeout) {
+ u64 mult;
+
+ mult = ((u64)ip_rt_gc_interval) << rt_hash_log;
+ if (ip_rt_gc_timeout > 1)
+ do_div(mult, ip_rt_gc_timeout);
+ goal = (unsigned int)mult;
+ if (goal > rt_hash_mask) goal = rt_hash_mask + 1;
+ for (; goal > 0; goal--) {
unsigned long tmo = ip_rt_gc_timeout;
i = (i + 1) & rt_hash_mask;
rthp = &rt_hash_table[i].chain;
+ if (*rthp == 0)
+ continue;
spin_lock(rt_hash_lock_addr(i));
while ((rth = *rthp) != NULL) {
if (rth->u.dst.expires) {
@@ -658,7 +665,7 @@ static void rt_check_expire(unsigned long dummy)
break;
}
rover = i;
- mod_timer(&rt_periodic_timer, now + ip_rt_gc_interval);
+ mod_timer(&rt_periodic_timer, jiffies + ip_rt_gc_interval);
}
/* This can run from both BH and non-BH contexts, the latter