[PATCH v5 1/7] hash: move table of hash compare functions out of header

Stephen Hemminger
2026-01-30T20:23:40Z

Remove the definition of the compare jump table from the
header file so the internal details are not exposed.
Prevents future ABI breakage if new sizes are added.

Make other macros local if possible, header should
only contain exposed API.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
---
lib/hash/rte_cuckoo_hash.c | 74 ++++++++++++++++++++++++++++++-----
lib/hash/rte_cuckoo_hash.h | 79 +-------------------------------------
2 files changed, 65 insertions(+), 88 deletions(-)

diff --git a/lib/hash/rte_cuckoo_hash.c b/lib/hash/rte_cuckoo_hash.c
index 2c92c51624..619fe0c691 100644
--- a/lib/hash/rte_cuckoo_hash.c
+++ b/lib/hash/rte_cuckoo_hash.c
@@ -25,14 +25,51 @@
#include <rte_tailq.h>

#include "rte_hash.h"
+#include "rte_cuckoo_hash.h"

-/* needs to be before rte_cuckoo_hash.h */
RTE_LOG_REGISTER_DEFAULT(hash_logtype, INFO);
#define RTE_LOGTYPE_HASH hash_logtype
#define HASH_LOG(level, ...) \
RTE_LOG_LINE(level, HASH, "" __VA_ARGS__)

-#include "rte_cuckoo_hash.h"
+/* Macro to enable/disable run-time checking of function parameters */
+#if defined(RTE_LIBRTE_HASH_DEBUG)
+#define RETURN_IF_TRUE(cond, retval) do { \
+ if (cond) \
+ return retval; \
+} while (0)
+#else
+#define RETURN_IF_TRUE(cond, retval)
+#endif
+
+#if defined(RTE_ARCH_X86)
+#include "rte_cmp_x86.h"
+#endif
+
+#if defined(RTE_ARCH_ARM64)
+#include "rte_cmp_arm64.h"
+#endif
+
+/*
+ * All different options to select a key compare function,
+ * based on the key size and custom function.
+ * Not in rte_cuckoo_hash.h to avoid ABI issues.
+ */
+enum cmp_jump_table_case {
+ KEY_CUSTOM = 0,
+#if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
+ KEY_16_BYTES,
+ KEY_32_BYTES,
+ KEY_48_BYTES,
+ KEY_64_BYTES,
+ KEY_80_BYTES,
+ KEY_96_BYTES,
+ KEY_112_BYTES,
+ KEY_128_BYTES,
+#endif
+ KEY_OTHER_BYTES,
+ NUM_KEY_CMP_CASES,
+};

/* Enum used to select the implementation of the signature comparison function to use
* eg: a system supporting SVE might want to use a NEON or scalar implementation.
@@ -117,6 +154,25 @@ void rte_hash_set_cmp_func(struct rte_hash *h, rte_hash_cmp_eq_t func)
h->rte_hash_custom_cmp_eq = func;
}

+/*
+ * Table storing all different key compare functions
+ * (multi-process supported)
+ */
+static const rte_hash_cmp_eq_t cmp_jump_table[NUM_KEY_CMP_CASES] = {
+ [KEY_CUSTOM] = NULL,
+#if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
+ [KEY_16_BYTES] = rte_hash_k16_cmp_eq,
+ [KEY_32_BYTES] = rte_hash_k32_cmp_eq,
+ [KEY_48_BYTES] = rte_hash_k48_cmp_eq,
+ [KEY_64_BYTES] = rte_hash_k64_cmp_eq,
+ [KEY_80_BYTES] = rte_hash_k80_cmp_eq,
+ [KEY_96_BYTES] = rte_hash_k96_cmp_eq,
+ [KEY_112_BYTES] = rte_hash_k112_cmp_eq,
+ [KEY_128_BYTES] = rte_hash_k128_cmp_eq,
+#endif
+ [KEY_OTHER_BYTES] = memcmp,
+};
+
static inline int
rte_hash_cmp_eq(const void *key1, const void *key2, const struct rte_hash *h)
{
@@ -390,13 +446,13 @@ rte_hash_create(const struct rte_hash_parameters *params)
goto err_unlock;
}

-/*
- * If x86 architecture is used, select appropriate compare function,
- * which may use x86 intrinsics, otherwise use memcmp
- */
-#if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
/* Select function to compare keys */
switch (params->key_len) {
+#if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
+ /*
+ * If x86 architecture is used, select appropriate compare function,
+ * which may use x86 intrinsics, otherwise use memcmp
+ */
case 16:
h->cmp_jump_table_idx = KEY_16_BYTES;
break;
@@ -421,13 +477,11 @@ rte_hash_create(const struct rte_hash_parameters *params)
case 128:
h->cmp_jump_table_idx = KEY_128_BYTES;
break;
+#endif
default:
/* If key is not multiple of 16, use generic memcmp */
h->cmp_jump_table_idx = KEY_OTHER_BYTES;
}
-#else
- h->cmp_jump_table_idx = KEY_OTHER_BYTES;
-#endif

if (use_local_cache) {
local_free_slots = rte_zmalloc_socket(NULL,
diff --git a/lib/hash/rte_cuckoo_hash.h b/lib/hash/rte_cuckoo_hash.h
index cf5cd29144..5b3c51348e 100644
--- a/lib/hash/rte_cuckoo_hash.h
+++ b/lib/hash/rte_cuckoo_hash.h
@@ -12,86 +12,9 @@
#define _RTE_CUCKOO_HASH_H_

#include <stdalign.h>
-
-#if defined(RTE_ARCH_X86)
-#include "rte_cmp_x86.h"
-#endif
-
-#if defined(RTE_ARCH_ARM64)
-#include "rte_cmp_arm64.h"
-#endif
-
-/* Macro to enable/disable run-time checking of function parameters */
-#if defined(RTE_LIBRTE_HASH_DEBUG)
-#define RETURN_IF_TRUE(cond, retval) do { \
- if (cond) \
- return retval; \
-} while (0)
-#else
-#define RETURN_IF_TRUE(cond, retval)
-#endif
-
#include <rte_hash_crc.h>
#include <rte_jhash.h>

-#if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
-/*
- * All different options to select a key compare function,
- * based on the key size and custom function.
- */
-enum cmp_jump_table_case {
- KEY_CUSTOM = 0,
- KEY_16_BYTES,
- KEY_32_BYTES,
- KEY_48_BYTES,
- KEY_64_BYTES,
- KEY_80_BYTES,
- KEY_96_BYTES,
- KEY_112_BYTES,
- KEY_128_BYTES,
- KEY_OTHER_BYTES,
- NUM_KEY_CMP_CASES,
-};
-
-/*
- * Table storing all different key compare functions
- * (multi-process supported)
- */
-const rte_hash_cmp_eq_t cmp_jump_table[NUM_KEY_CMP_CASES] = {
- NULL,
- rte_hash_k16_cmp_eq,
- rte_hash_k32_cmp_eq,
- rte_hash_k48_cmp_eq,
- rte_hash_k64_cmp_eq,
- rte_hash_k80_cmp_eq,
- rte_hash_k96_cmp_eq,
- rte_hash_k112_cmp_eq,
- rte_hash_k128_cmp_eq,
- memcmp
-};
-#else
-/*
- * All different options to select a key compare function,
- * based on the key size and custom function.
- */
-enum cmp_jump_table_case {
- KEY_CUSTOM = 0,
- KEY_OTHER_BYTES,
- NUM_KEY_CMP_CASES,
-};
-
-/*
- * Table storing all different key compare functions
- * (multi-process supported)
- */
-const rte_hash_cmp_eq_t cmp_jump_table[NUM_KEY_CMP_CASES] = {
- NULL,
- memcmp
-};
-
-#endif
-
-
/**
* Number of items per bucket.
* 8 is a tradeoff between performance and memory consumption.
@@ -189,7 +112,7 @@ struct __rte_cache_aligned rte_hash {
uint32_t hash_func_init_val; /**< Init value used by hash_func. */
rte_hash_cmp_eq_t rte_hash_custom_cmp_eq;
/**< Custom function used to compare keys. */
- enum cmp_jump_table_case cmp_jump_table_idx;
+ unsigned int cmp_jump_table_idx;
/**< Indicates which compare function to use. */
unsigned int sig_cmp_fn;
/**< Indicates which signature compare function to use. */
--
2.51.0