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| author | Eric Dumazet <dada1@cosmosbay.com> | 2005-07-05 15:00:32 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-07-05 15:00:32 -0700 |
| commit | bb1d23b02657f494dff295f6cdd1f29df30fa61e (patch) | |
| tree | 59c170cb94d2f65a0717ea67e169b3e2e22be11e /net | |
| parent | 424c4b70cc4ff3930ee36a2ef7b204e4d704fd26 (diff) | |
| download | linux-bb1d23b02657f494dff295f6cdd1f29df30fa61e.tar.bz2 | |
[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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/route.c | 21 |
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 |