[NET]: Make macro to specify the ptype_base size

Currently this size is 16, but as the comment says this
is so only because all the chains (except one) has the
length 1. I think, that some day this may change, so
growing this hash will be much easier.

Besides, symbolic names are read better than magic constants.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index d0e23d8..d0d2675 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -150,8 +150,11 @@
  *             86DD    IPv6
  */
 
+#define PTYPE_HASH_SIZE        (16)
+#define PTYPE_HASH_MASK        (PTYPE_HASH_SIZE - 1)
+
 static DEFINE_SPINLOCK(ptype_lock);
-static struct list_head ptype_base[16] __read_mostly;  /* 16 way hashed list */
+static struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly;
 static struct list_head ptype_all __read_mostly;       /* Taps */
 
 #ifdef CONFIG_NET_DMA
@@ -362,7 +365,7 @@ void dev_add_pack(struct packet_type *pt)
        if (pt->type == htons(ETH_P_ALL))
                list_add_rcu(&pt->list, &ptype_all);
        else {
-               hash = ntohs(pt->type) & 15;
+               hash = ntohs(pt->type) & PTYPE_HASH_MASK;
                list_add_rcu(&pt->list, &ptype_base[hash]);
        }
        spin_unlock_bh(&ptype_lock);
@@ -391,7 +394,7 @@ void __dev_remove_pack(struct packet_type *pt)
        if (pt->type == htons(ETH_P_ALL))
                head = &ptype_all;
        else
-               head = &ptype_base[ntohs(pt->type) & 15];
+               head = &ptype_base[ntohs(pt->type) & PTYPE_HASH_MASK];
 
        list_for_each_entry(pt1, head, list) {
                if (pt == pt1) {
@@ -1420,7 +1423,8 @@ struct sk_buff *skb_gso_segment(struct sk_buff *skb, int features)
        }
 
        rcu_read_lock();
-       list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type) & 15], list) {
+       list_for_each_entry_rcu(ptype,
+                       &ptype_base[ntohs(type) & PTYPE_HASH_MASK], list) {
                if (ptype->type == type && !ptype->dev && ptype->gso_segment) {
                        if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
                                err = ptype->gso_send_check(skb);
@@ -2077,7 +2081,8 @@ ncls:
                goto out;
 
        type = skb->protocol;
-       list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type)&15], list) {
+       list_for_each_entry_rcu(ptype,
+                       &ptype_base[ntohs(type) & PTYPE_HASH_MASK], list) {
                if (ptype->type == type &&
                    (!ptype->dev || ptype->dev == skb->dev)) {
                        if (pt_prev)
@@ -2525,7 +2530,7 @@ static void *ptype_get_idx(loff_t pos)
                ++i;
        }
 
-       for (t = 0; t < 16; t++) {
+       for (t = 0; t < PTYPE_HASH_SIZE; t++) {
                list_for_each_entry_rcu(pt, &ptype_base[t], list) {
                        if (i == pos)
                                return pt;
@@ -2559,10 +2564,10 @@ static void *ptype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
                hash = 0;
                nxt = ptype_base[0].next;
        } else
-               hash = ntohs(pt->type) & 15;
+               hash = ntohs(pt->type) & PTYPE_HASH_MASK;
 
        while (nxt == &ptype_base[hash]) {
-               if (++hash >= 16)
+               if (++hash >= PTYPE_HASH_SIZE)
                        return NULL;
                nxt = ptype_base[hash].next;
        }
@@ -4398,7 +4403,7 @@ static int __init net_dev_init(void)
                goto out;
 
        INIT_LIST_HEAD(&ptype_all);
-       for (i = 0; i < 16; i++)
+       for (i = 0; i < PTYPE_HASH_SIZE; i++)
                INIT_LIST_HEAD(&ptype_base[i]);
 
        if (register_pernet_subsys(&netdev_net_ops))