The patch 9497df88ab5567daa001829051c5f87161a81ff0 ("rhashtable:
Fix reader/rehash race") added a pair of barriers. In fact the
wmb is superfluous because every subsequent write to the old or
new hash table uses rcu_assign_pointer, which itself carriers a
full barrier prior to the assignment.
Therefore we may remove the explicit wmb.
Signed-off-by: Herbert Xu <[email protected]>
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 1c624db..d1f94b4 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -232,9 +232,6 @@ static int rhashtable_rehash_attach(struct rhashtable *ht,
*/
rcu_assign_pointer(old_tbl->future_tbl, new_tbl);
- /* Ensure the new table is visible to readers. */
- smp_wmb();
-
spin_unlock_bh(old_tbl->locks);
return 0;
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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