[dpdk-dev] [PATCH] hash: validate hash bucket entries while compiling

[Honnappa Nagarahalli]

Validate RTE_HASH_BUCKET_ENTRIES during compilation instead of
run time.

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>
Reviewed-by: Gavin Hu <gavin.hu at arm.com>
---
 lib/librte_eal/common/include/rte_common.h | 5 +++++
 lib/librte_hash/rte_cuckoo_hash.c          | 1 -
 lib/librte_hash/rte_cuckoo_hash.h          | 4 ++++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 434adfd45..a9df7c161 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -293,6 +293,11 @@ rte_combine64ms1b(register uint64_t v)
 
 /*********** Macros to work with powers of 2 ********/
 
+/**
+ * Macro to return 1 if n is a power of 2, 0 otherwise
+ */
+#define RTE_IS_POWER_OF_2(n) ((n) && !(((n) - 1) & (n)))
+
 /**
  * Returns true if n is a power of 2
  * @param n
diff --git a/lib/librte_hash/rte_cuckoo_hash.c b/lib/librte_hash/rte_cuckoo_hash.c
index a07543a29..375e7d208 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -107,7 +107,6 @@ rte_hash_create(const struct rte_hash_parameters *params)
 	/* Check for valid parameters */
 	if ((params->entries > RTE_HASH_ENTRIES_MAX) ||
 			(params->entries < RTE_HASH_BUCKET_ENTRIES) ||
-			!rte_is_power_of_2(RTE_HASH_BUCKET_ENTRIES) ||
 			(params->key_len == 0)) {
 		rte_errno = EINVAL;
 		RTE_LOG(ERR, HASH, "rte_hash_create has invalid parameters\n");
diff --git a/lib/librte_hash/rte_cuckoo_hash.h b/lib/librte_hash/rte_cuckoo_hash.h
index 7a54e5557..bd6ad1bd6 100644
--- a/lib/librte_hash/rte_cuckoo_hash.h
+++ b/lib/librte_hash/rte_cuckoo_hash.h
@@ -97,6 +97,10 @@ enum add_key_case {
 /** Number of items per bucket. */
 #define RTE_HASH_BUCKET_ENTRIES		8
 
+#if !RTE_IS_POWER_OF_2(RTE_HASH_BUCKET_ENTRIES)
+#error RTE_HASH_BUCKET_ENTRIES must be a power of 2
+#endif
+
 #define NULL_SIGNATURE			0
 
 #define EMPTY_SLOT			0
-- 
2.14.1