atm-14-clip-neigh-lock.patch

   1 >thursday.  the box is still up and oops-free this morning.  so, we
   2 >definately have an smp problem here...
   3
   4 its a start!
   5
   6 >now, how in the world do we go about tracking something like this down?
   7
   8 try the following patch.  the neighbour code in clip seems a bit
   9 non-standard -- there might be other lossage
  10
  11 Index: net/atm/clip.c
  12 ===================================================================
  13 RCS file: /afs/cmf/project/cvsroot/linux/net/atm/clip.c,v
  14 retrieving revision 1.8
  15 diff -u -r1.8 clip.c
  16 --- net/atm/clip.c      7 Mar 2003 18:54:44 -0000       1.8
  17 +++ net/atm/clip.c      10 Mar 2003 12:33:43 -0000
  18 @@ -121,13 +121,15 @@
  19         /*DPRINTK("idle_timer_check\n");*/
  20         write_lock(&clip_tbl.lock);
  21         for (i = 0; i <= NEIGH_HASHMASK; i++) {
  22 -               struct neighbour **np;
  23 +               struct neighbour *n, **np;
  24
  25 -               for (np = &clip_tbl.hash_buckets[i]; *np;) {
  26 -                       struct neighbour *n = *np;
  27 +               np = &clip_tbl.hash_buckets[i];
  28 +               while ((n = *np) != NULL) {
  29                         struct atmarp_entry *entry = NEIGH2ENTRY(n);
  30                         struct clip_vcc *clip_vcc;
  31
  32 +                       write_lock(&n->lock);
  33 +
  34                         for (clip_vcc = entry->vccs; clip_vcc;
  35                             clip_vcc = clip_vcc->next)
  36                                 if (clip_vcc->idle_timeout &&
  37 @@ -139,8 +141,10 @@
  38                                         atm_async_release_vcc(clip_vcc->vcc,
  39                                             -ETIMEDOUT);
  40                                 }
  41 +
  42                         if (entry->vccs ||
  43                             time_before(jiffies, entry->expires)) {
  44 +                               write_unlock(&n->lock);
  45                                 np = &n->next;
  46                                 continue;
  47                         }
  48 @@ -152,12 +156,14 @@
  49                                 while ((skb = skb_dequeue(&n->arp_queue)) !=
  50                                      NULL)
  51                                         dev_kfree_skb(skb);
  52 +                               write_unlock(&n->lock);
  53                                 np = &n->next;
  54                                 continue;
  55                         }
  56                         *np = n->next;
  57                         DPRINTK("expired neigh %p\n",n);
  58                         n->dead = 1;
  59 +                       write_unlock(&n->lock);
  60                         neigh_release(n);
  61                 }
  62         }
  63
  64
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