rhashtable: Add rehash counter to bucket_table

This patch adds a rehash counter to bucket_table to indicate
the last bucket that has been rehashed.  This serves two purposes:

1. Any bucket that has been rehashed can never gain a new object.
2. If the rehash counter reaches the size of the table, the table
will forever remain empty.

This patch also downsizes bucket_table->size to an unsigned int
since we do not support sizes greater than 32 bits yet.

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

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index a0abddd226b3..ed7562ad4ca0 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -49,6 +49,7 @@ struct rhash_head {
 /**
  * struct bucket_table - Table of hash buckets
  * @size: Number of hash buckets
+ * @rehash: Current bucket being rehashed
  * @hash_rnd: Random seed to fold into hash
  * @shift: Current size (1 << shift)
  * @locks_mask: Mask to apply before accessing locks[]
@@ -58,7 +59,8 @@ struct rhash_head {
  * @buckets: size * hash buckets
  */
 struct bucket_table {
-        size_t                  size;
+        unsigned int            size;
+        unsigned int            rehash;
         u32                     hash_rnd;
         u32                     shift;
         unsigned int            locks_mask;