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rhashtable: Kill harmless RCU warning in rhashtable_walk_init

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The commit c6ff5268293ef98e48a99597e765ffc417e39fa5 ("rhashtable:
Fix walker list corruption") causes a suspicious RCU usage warning
because we no longer hold ht->mutex when we dereference ht->tbl.

However, this is a false positive because we now hold ht->lock
which also guarantees that ht->tbl won't disppear from under us.

This patch kills the warning by using rcu_dereference_protected.

Reported-by: kernel test robot <ying.huang@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2015-12-19 10:45:28 +08:00 committed by David S. Miller
parent e905eabc90
commit 179ccc0a73
1 changed files with 2 additions and 1 deletions
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3
lib/rhashtable.c
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@ -519,7 +519,8 @@ int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter)
return -ENOMEM;
spin_lock(&ht->lock);
iter->walker->tbl = rht_dereference(ht->tbl, ht);
iter->walker->tbl =
rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock));
list_add(&iter->walker->list, &iter->walker->tbl->walkers);
spin_unlock(&ht->lock);