[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>

1 files changed, 14 insertions, 9 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index d0e23d8310ff..d0d2675aaed6 100644
--- 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))