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Message-Id: <96e2bb79b25fc548012d135310719b8b3b4c7514.1423097592.git.tgraf@suug.ch>
Date: Thu, 5 Feb 2015 02:03:35 +0100
From: Thomas Graf <tgraf@...g.ch>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, herbert@...dor.apana.org.au,
ying.xue@...driver.com
Subject: [PATCH 5/6] rhashtable: Add more lock verification
Catch hash miscalculations which result in hard to track down race
conditions.
Signed-off-by: Thomas Graf <tgraf@...g.ch>
---
lib/rhashtable.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index c2c3949..ef0816b 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -348,9 +348,11 @@ static bool hashtable_chain_unzip(struct rhashtable *ht,
return !rht_is_a_nulls(p);
}
-static void link_old_to_new(struct bucket_table *new_tbl,
+static void link_old_to_new(struct rhashtable *ht, struct bucket_table *new_tbl,
unsigned int new_hash, struct rhash_head *entry)
{
+ ASSERT_BUCKET_LOCK(ht, new_tbl, new_hash);
+
rcu_assign_pointer(*bucket_tail(new_tbl, new_hash), entry);
}
@@ -406,7 +408,7 @@ int rhashtable_expand(struct rhashtable *ht)
lock_buckets(new_tbl, old_tbl, new_hash);
rht_for_each(he, old_tbl, old_hash) {
if (head_hashfn(ht, new_tbl, he) == new_hash) {
- link_old_to_new(new_tbl, new_hash, he);
+ link_old_to_new(ht, new_tbl, new_hash, he);
break;
}
}
@@ -492,6 +494,7 @@ int rhashtable_shrink(struct rhashtable *ht)
rcu_assign_pointer(*bucket_tail(new_tbl, new_hash),
tbl->buckets[new_hash]);
+ ASSERT_BUCKET_LOCK(ht, tbl, new_hash + new_tbl->size);
rcu_assign_pointer(*bucket_tail(new_tbl, new_hash),
tbl->buckets[new_hash + new_tbl->size]);
@@ -557,6 +560,8 @@ static void __rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,
struct rhash_head *head = rht_dereference_bucket(tbl->buckets[hash],
tbl, hash);
+ ASSERT_BUCKET_LOCK(ht, tbl, hash);
+
if (rht_is_a_nulls(head))
INIT_RHT_NULLS_HEAD(obj->next, ht, hash);
else
@@ -641,6 +646,7 @@ restart:
continue;
}
+ ASSERT_BUCKET_LOCK(ht, tbl, hash);
rcu_assign_pointer(*pprev, obj->next);
ret = true;
--
1.9.3
--
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