[dpdk-dev] [PATCH v3 1/3] hash: fix position bug in 'free key with position'

[Dharmik Thakkar <dharmik.thakkar@arm.com>]

Currently, in rte_hash_free_key_with_position(), the position returned
to the ring of free_slots leads to an unexpected conflict with a key
already in use.

This patch fixes incorrect position returned to the ring of free_slots.

Bugzilla ID: 261
Fixes: 9d033dac7d7c ("hash: support no free on delete")
Cc: honnappa.nagarahalli@arm.com
Cc: stable@dpdk.org

Reported-by: Linfan <zhongdahulinfan@163.com>
Suggested-by: Linfan <zhongdahulinfan@163.com>
Signed-off-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
---
 lib/librte_hash/rte_cuckoo_hash.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
index 261267b7fd3d..8646ca52e60b 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -1587,14 +1587,17 @@ int __rte_experimental
 rte_hash_free_key_with_position(const struct rte_hash *h,
 				const int32_t position)
 {
-	RETURN_IF_TRUE(((h == NULL) || (position == EMPTY_SLOT)), -EINVAL);
+	/*  Key index where key is stored, adding the first dummy index*/
+	uint32_t key_idx = position + 1;
+
+	RETURN_IF_TRUE(((h == NULL) || (key_idx == EMPTY_SLOT)), -EINVAL);
 
 	unsigned int lcore_id, n_slots;
 	struct lcore_cache *cached_free_slots;
 	const int32_t total_entries = h->num_buckets * RTE_HASH_BUCKET_ENTRIES;
 
 	/* Out of bounds */
-	if (position >= total_entries)
+	if (key_idx >= total_entries)
 		return -EINVAL;
 	if (h->ext_table_support && h->readwrite_concur_lf_support) {
 		uint32_t index = h->ext_bkt_to_free[position];
@@ -1619,11 +1622,11 @@ rte_hash_free_key_with_position(const struct rte_hash *h,
 		}
 		/* Put index of new free slot in cache. */
 		cached_free_slots->objs[cached_free_slots->len] =
-					(void *)((uintptr_t)position);
+					(void *)((uintptr_t)key_idx);
 		cached_free_slots->len++;
 	} else {
 		rte_ring_sp_enqueue(h->free_slots,
-				(void *)((uintptr_t)position));
+				(void *)((uintptr_t)key_idx));
 	}
 
 	return 0;
-- 
2.17.1