[PATCH net v4 1/2] rhashtable: Fix rhlist duplicates insertion

[Paul Blakey <paulb@mellanox.com>]

When inserting duplicate objects (those with the same key),
current rhlist implementation messes up the chain pointers by
updating the bucket pointer instead of prev next pointer to the
newly inserted node. This causes missing elements on removal and
travesal.

Fix that by properly updating pprev pointer to point to
the correct rhash_head next pointer.

Fixes: ca26893f05e8 ('rhashtable: Add rhlist interface')
Signed-off-by: Paul Blakey <paulb@mellanox.com>
---
 include/linux/rhashtable.h | 4 +++-
 lib/rhashtable.c           | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index c9df252..668a21f 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -766,8 +766,10 @@ static inline void *__rhashtable_insert_fast(
 		if (!key ||
 		    (params.obj_cmpfn ?
 		     params.obj_cmpfn(&arg, rht_obj(ht, head)) :
-		     rhashtable_compare(&arg, rht_obj(ht, head))))
+		     rhashtable_compare(&arg, rht_obj(ht, head)))) {
+			pprev = &head->next;
 			continue;
+		}
 
 		data = rht_obj(ht, head);
 
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 3825c30..47de025 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -506,8 +506,10 @@ static void *rhashtable_lookup_one(struct rhashtable *ht,
 		if (!key ||
 		    (ht->p.obj_cmpfn ?
 		     ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) :
-		     rhashtable_compare(&arg, rht_obj(ht, head))))
+		     rhashtable_compare(&arg, rht_obj(ht, head)))) {
+			pprev = &head->next;
 			continue;
+		}
 
 		if (!ht->rhlist)
 			return rht_obj(ht, head);
-- 
1.8.4.3