: Abstract neigh table walking

diff -Nru a/net/atm/clip.c b/net/atm/clip.c
@@ -123,64 +123,49 @@
 	spin_unlock_bh(&entry->neigh->dev->xmit_lock);
 }
 
-
-static void idle_timer_check(unsigned long dummy)
+/* The neighbour entry n->lock is held. */
+static int neigh_check_cb(struct neighbour *n)
 {
-	int i;
+	struct atmarp_entry *entry = NEIGH2ENTRY(n);
+	struct clip_vcc *cv;
 
-	/*DPRINTK("idle_timer_check\n");*/
-	write_lock(&clip_tbl.lock);
-	for (i = 0; i <= NEIGH_HASHMASK; i++) {
-		struct neighbour **np;
+	for (cv = entry->vccs; cv; cv = cv->next) {
+		unsigned long exp = cv->last_use + cv->idle_timeout;
 
-		for (np = &clip_tbl.hash_buckets[i]; *np;) {
-			struct neighbour *n = *np;
-			struct atmarp_entry *entry = NEIGH2ENTRY(n);
-			struct clip_vcc *clip_vcc;
-
-			write_lock(&n->lock);
-
-			for (clip_vcc = entry->vccs; clip_vcc;
-			    clip_vcc = clip_vcc->next)
-				if (clip_vcc->idle_timeout &&
-				    time_after(jiffies, clip_vcc->last_use+
-				    clip_vcc->idle_timeout)) {
-					DPRINTK("releasing vcc %p->%p of "
-					    "entry %p\n",clip_vcc,clip_vcc->vcc,
-					    entry);
-					vcc_release_async(clip_vcc->vcc,
-							  -ETIMEDOUT);
-				}
-			if (entry->vccs ||
-			    time_before(jiffies, entry->expires)) {
-				np = &n->next;
-				write_unlock(&n->lock);
-				continue;
-			}
-			if (atomic_read(&n->refcnt) > 1) {
-				struct sk_buff *skb;
-
-				DPRINTK("destruction postponed with ref %d\n",
-				    atomic_read(&n->refcnt));
-				while ((skb = skb_dequeue(&n->arp_queue)) !=
-				     NULL) 
-					dev_kfree_skb(skb);
-				np = &n->next;
-				write_unlock(&n->lock);
-				continue;
-			}
-			*np = n->next;
-			DPRINTK("expired neigh %p\n",n);
-			n->dead = 1;
-			write_unlock(&n->lock);
-			neigh_release(n);
+		if (cv->idle_timeout && time_after(jiffies, exp)) {
+			DPRINTK("releasing vcc %p->%p of entry %p\n",
+				cv, cv->vcc, entry);
+			vcc_release_async(cv->vcc, -ETIMEDOUT);
 		}
 	}
+
+	if (entry->vccs || time_before(jiffies, entry->expires))
+		return 0;
+
+	if (atomic_read(&n->refcnt) > 1) {
+		struct sk_buff *skb;
+
+		DPRINTK("destruction postponed with ref %d\n",
+			atomic_read(&n->refcnt));
+
+		while ((skb = skb_dequeue(&n->arp_queue)) != NULL) 
+			dev_kfree_skb(skb);
+
+		return 0;
+	}
+
+	DPRINTK("expired neigh %p\n",n);
+	return 1;
+}
+
+static void idle_timer_check(unsigned long dummy)
+{
+	write_lock(&clip_tbl.lock);
+	__neigh_for_each_release(&clip_tbl, neigh_check_cb);
 	mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);
 	write_unlock(&clip_tbl.lock);
 }
 
-
 static int clip_arp_rcv(struct sk_buff *skb)
 {
 	struct atm_vcc *vcc;

@@ -833,120 +818,126 @@
 	}
 }
 
+/* This means the neighbour entry has no attached VCC objects. */
+#define SEQ_NO_VCC_TOKEN	((void *) 2)
+
 static void atmarp_info(struct seq_file *seq, struct net_device *dev,
 			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
 {
+	unsigned long exp;
 	char buf[17];
-	int svc, off;
+	int svc, llc, off;
+
+	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
+	       (clip_vcc->vcc->sk->sk_family == AF_ATMSVC));
+
+	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
+	       clip_vcc->encap);
+
+	if (clip_vcc == SEQ_NO_VCC_TOKEN)
+		exp = entry->neigh->used;
+	else
+		exp = clip_vcc->last_use;
 
-	svc = !clip_vcc || clip_vcc->vcc->sk->sk_family == AF_ATMSVC;
-	seq_printf(seq, "%-6s%-4s%-4s%5ld ", dev->name, svc ? "SVC" : "PVC",
-	    !clip_vcc || clip_vcc->encap ? "LLC" : "NULL",
-	    (jiffies-(clip_vcc ? clip_vcc->last_use : entry->neigh->used))/HZ);
+	exp = (jiffies - exp) / HZ;
 
-	off = scnprintf(buf, sizeof(buf) - 1, "%d.%d.%d.%d", NIPQUAD(entry->ip));
+	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
+		   dev->name,
+		   svc ? "SVC" : "PVC",
+		   llc ? "LLC" : "NULL",
+		   exp);
+
+	off = scnprintf(buf, sizeof(buf) - 1, "%d.%d.%d.%d",
+			NIPQUAD(entry->ip));
 	while (off < 16)
 		buf[off++] = ' ';
 	buf[off] = '\0';
 	seq_printf(seq, "%s", buf);
 
-	if (!clip_vcc) {
+	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
 		if (time_before(jiffies, entry->expires))
 			seq_printf(seq, "(resolving)\n");
 		else
 			seq_printf(seq, "(expired, ref %d)\n",
 				   atomic_read(&entry->neigh->refcnt));
 	} else if (!svc) {
-		seq_printf(seq, "%d.%d.%d\n", clip_vcc->vcc->dev->number,
-			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
+		seq_printf(seq, "%d.%d.%d\n",
+			   clip_vcc->vcc->dev->number,
+			   clip_vcc->vcc->vpi,
+			   clip_vcc->vcc->vci);
 	} else {
 		svc_addr(seq, &clip_vcc->vcc->remote);
 		seq_putc(seq, '\n');
 	}
 }
 
-struct arp_state {
-	int bucket;
-  	struct neighbour *n;
+struct clip_seq_state {
+	/* This member must be first. */
+	struct neigh_seq_state ns;
+
+	/* Local to clip specific iteration. */
 	struct clip_vcc *vcc;
 };
-  
-static void *arp_vcc_walk(struct arp_state *state,
-			  struct atmarp_entry *e, loff_t *l)
-{
-	struct clip_vcc *vcc = state->vcc;
 
-	if (!vcc)
-		vcc = e->vccs;
-	if (vcc == (void *)1) {
-		vcc = e->vccs;
-		--*l;
-  	}
-	for (; vcc; vcc = vcc->next) {
-		if (--*l < 0)
-			break;
-	}
-	state->vcc = vcc;
-	return (*l < 0) ? state : NULL;
-}
-  
-static void *arp_get_idx(struct arp_state *state, loff_t l)
+static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
+					  struct clip_vcc *curr)
 {
-	void *v = NULL;
-
-	for (; state->bucket <= NEIGH_HASHMASK; state->bucket++) {
-		for (; state->n; state->n = state->n->next) {
-			v = arp_vcc_walk(state, NEIGH2ENTRY(state->n), &l);
-			if (v)
-				goto done;
-  		}
-		state->n = clip_tbl.hash_buckets[state->bucket + 1];
+	if (!curr) {
+		curr = e->vccs;
+		if (!curr)
+			return SEQ_NO_VCC_TOKEN;
+		return curr;
 	}
-done:
-	return v;
+	if (curr == SEQ_NO_VCC_TOKEN)
+		return NULL;
+
+	curr = curr->next;
+
+	return curr;
 }
 
-static void *arp_seq_start(struct seq_file *seq, loff_t *pos)
+static void *clip_seq_vcc_walk(struct clip_seq_state *state,
+			       struct atmarp_entry *e, loff_t *pos)
 {
-	struct arp_state *state = seq->private;
-	void *ret = (void *)1;
+	struct clip_vcc *vcc = state->vcc;
 
-	read_lock_bh(&clip_tbl.lock);
-	state->bucket = 0;
-	state->n = clip_tbl.hash_buckets[0];
-	state->vcc = (void *)1;
-	if (*pos)
-		ret = arp_get_idx(state, *pos);
-	return ret;
-}
+	vcc = clip_seq_next_vcc(e, vcc);
+	if (vcc && pos != NULL) {
+		while (*pos) {
+			vcc = clip_seq_next_vcc(e, vcc);
+			if (!vcc)
+				break;
+			--(*pos);
+		}
+	}
+	state->vcc = vcc;
 
-static void arp_seq_stop(struct seq_file *seq, void *v)
+	return vcc;
+}
+  
+static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
+			       struct neighbour *n, loff_t *pos)
 {
-	struct arp_state *state = seq->private;
+	struct clip_seq_state *state = (struct clip_seq_state *) _state;
 
-	if (state->bucket != -1)
-		read_unlock_bh(&clip_tbl.lock);
+	return clip_seq_vcc_walk(state, NEIGH2ENTRY(n), pos);
 }
 
-static void *arp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+static void *clip_seq_start(struct seq_file *seq, loff_t *pos)
 {
-	struct arp_state *state = seq->private;
-
-	v = arp_get_idx(state, 1);
-	*pos += !!PTR_ERR(v);
-	return v;
+	return neigh_seq_start(seq, pos, &clip_tbl, NEIGH_SEQ_NEIGH_ONLY);
 }
 
-static int arp_seq_show(struct seq_file *seq, void *v)
+static int clip_seq_show(struct seq_file *seq, void *v)
 {
 	static char atm_arp_banner[] = 
 		"IPitf TypeEncp Idle IP address      ATM address\n";
 
-	if (v == (void *)1)
+	if (v == SEQ_START_TOKEN) {
 		seq_puts(seq, atm_arp_banner);
-	else {
-		struct arp_state *state = seq->private;
-		struct neighbour *n = state->n;	
+	} else {
+		struct clip_seq_state *state = seq->private;
+		struct neighbour *n = v;
 		struct clip_vcc *vcc = state->vcc;
 
 		atmarp_info(seq, n->dev, NEIGH2ENTRY(n), vcc);

@@ -955,15 +946,15 @@
 }
 
 static struct seq_operations arp_seq_ops = {
-	.start	= arp_seq_start,
-	.next	= arp_seq_next,
-	.stop	= arp_seq_stop,
-	.show	= arp_seq_show,
+	.start	= clip_seq_start,
+	.next	= neigh_seq_next,
+	.stop	= neigh_seq_stop,
+	.show	= clip_seq_show,
 };
 
 static int arp_seq_open(struct inode *inode, struct file *file)
 {
-	struct arp_state *state;
+	struct clip_seq_state *state;
 	struct seq_file *seq;
 	int rc = -EAGAIN;
 

@@ -972,6 +963,8 @@
 		rc = -ENOMEM;
 		goto out_kfree;
 	}
+	memset(state, 0, sizeof(*state));
+	state->ns.neigh_sub_iter = clip_seq_sub_iter;
 
 	rc = seq_open(file, &arp_seq_ops);
 	if (rc)

@@ -987,16 +980,11 @@
 	goto out;
 }
 
-static int arp_seq_release(struct inode *inode, struct file *file)
-{
-	return seq_release_private(inode, file);
-}
-
 static struct file_operations arp_seq_fops = {
 	.open		= arp_seq_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
-	.release	= arp_seq_release,
+	.release	= seq_release_private,
 	.owner		= THIS_MODULE
 };
 #endif

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