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From:   NeilBrown <neilb@suse.com>
To:     Thomas Graf <tgraf@suug.ch>,
        Herbert Xu <herbert@gondor.apana.org.au>
Date:   Fri, 01 Jun 2018 14:44:09 +1000
Subject: [PATCH 01/18] rhashtable: silence RCU warning in rhashtable_test.
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Message-ID: <152782824927.30340.12281188634659526226.stgit@noble>
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print_ht in rhashtable_test calls rht_dereference() with neither
RCU protection or the mutex.  This triggers an RCU warning.
So take the mutex to silence the warning.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
---
 lib/test_rhashtable.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index f4000c137dbe..bf92b7aa2a49 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -499,6 +499,8 @@ static unsigned int __init print_ht(struct rhltable *rhlt)
 	unsigned int i, cnt = 0;
 
 	ht = &rhlt->ht;
+	/* Take the mutex to avoid RCU warning */
+	mutex_lock(&ht->mutex);
 	tbl = rht_dereference(ht->tbl, ht);
 	for (i = 0; i < tbl->size; i++) {
 		struct rhash_head *pos, *next;
@@ -532,6 +534,7 @@ static unsigned int __init print_ht(struct rhltable *rhlt)
 		}
 	}
 	printk(KERN_ERR "\n---- ht: ----%s\n-------------\n", buff);
+	mutex_unlock(&ht->mutex);
 
 	return cnt;
 }