[PATCH] neigh: always use hash_mask under tbl lock

[Julian Anastasov]

        Make sure hash_mask is protected with tbl->lock in all
cases just like the hash_buckets.

Signed-off-by: Julian Anastasov <[EMAIL PROTECTED]>
---
        I just noticed this in sources. Let me know if such change
is valid and desired for 2.4 or stable tree. Compiles on 2.6.18 and
2.6.18-git18.

diff -urp v2.6.18-git18/linux/net/core/neighbour.c linux/net/core/neighbour.c
--- v2.6.18-git18/linux/net/core/neighbour.c    2006-10-03 01:50:15.000000000 
+0300
+++ linux/net/core/neighbour.c  2006-10-03 01:50:32.000000000 +0300
@@ -344,12 +344,12 @@ struct neighbour *neigh_lookup(struct ne
 {
        struct neighbour *n;
        int key_len = tbl->key_len;
-       u32 hash_val = tbl->hash(pkey, dev) & tbl->hash_mask;
+       u32 hash_val = tbl->hash(pkey, dev);

        NEIGH_CACHE_STAT_INC(tbl, lookups);

        read_lock_bh(&tbl->lock);
-       for (n = tbl->hash_buckets[hash_val]; n; n = n->next) {
+       for (n = tbl->hash_buckets[hash_val & tbl->hash_mask]; n; n = n->next) {
                if (dev == n->dev && !memcmp(n->primary_key, pkey, key_len)) {
                        neigh_hold(n);
                        NEIGH_CACHE_STAT_INC(tbl, hits);
@@ -364,12 +364,12 @@ struct neighbour *neigh_lookup_nodev(str
 {
        struct neighbour *n;
        int key_len = tbl->key_len;
-       u32 hash_val = tbl->hash(pkey, NULL) & tbl->hash_mask;
+       u32 hash_val = tbl->hash(pkey, NULL);

        NEIGH_CACHE_STAT_INC(tbl, lookups);

        read_lock_bh(&tbl->lock);
-       for (n = tbl->hash_buckets[hash_val]; n; n = n->next) {
+       for (n = tbl->hash_buckets[hash_val & tbl->hash_mask]; n; n = n->next) {
                if (!memcmp(n->primary_key, pkey, key_len)) {
                        neigh_hold(n);
                        NEIGH_CACHE_STAT_INC(tbl, hits);
@@ -1998,12 +1998,12 @@ static int neigh_dump_table(struct neigh
        int rc, h, s_h = cb->args[1];
        int idx, s_idx = idx = cb->args[2];

+       read_lock_bh(&tbl->lock);
        for (h = 0; h <= tbl->hash_mask; h++) {
                if (h < s_h)
                        continue;
                if (h > s_h)
                        s_idx = 0;
-               read_lock_bh(&tbl->lock);
                for (n = tbl->hash_buckets[h], idx = 0; n; n = n->next, idx++) {
                        if (idx < s_idx)
                                continue;
@@ -2016,8 +2016,8 @@ static int neigh_dump_table(struct neigh
                                goto out;
                        }
                }
-               read_unlock_bh(&tbl->lock);
        }
+       read_unlock_bh(&tbl->lock);
        rc = skb->len;
 out:
        cb->args[1] = h;

-
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