eal: add generic thread-local-storage functions

Add support for TLS functionality in EAL.

The following functions are added:
rte_thread_tls_key_create - create a TLS data key.
rte_thread_tls_key_delete - delete a TLS data key.
rte_thread_tls_value_set - set value bound to the TLS key
rte_thread_tls_value_get - get value bound to the TLS key

TLS key is defined by the new type rte_tls_key.

The API allocates the thread local storage (TLS) key.
Any thread of the process can subsequently use this key
to store and retrieve values that are local to the thread.

Those functions are added in addition to TLS capability
in rte_per_lcore.h to allow abstraction of the pthread
layer for all operating systems.

Windows implementation is under librte_eal/windows and
implemented using WIN32 API for Windows only.

Unix implementation is under librte_eal/unix and
implemented using pthread for UNIX compilation.

Signed-off-by: Tal Shnaiderman <talshn@nvidia.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>

lib/librte_eal/include/rte_thread.h

@@ -19,6 +19,11 @@
 extern "C" {
 #endif
 
+/**
+ * TLS key type, an opaque pointer.
+ */
+typedef struct eal_tls_key *rte_tls_key;
+
 /**
  * Set core affinity of the current thread.
  * Support both EAL and non-EAL thread and update TLS.
@@ -40,6 +45,66 @@ int rte_thread_set_affinity(rte_cpuset_t *cpusetp);
  */
 void rte_thread_get_affinity(rte_cpuset_t *cpusetp);
 
+/**
+ * Create a TLS data key visible to all threads in the process.
+ * the created key is later used to get/set a value.
+ * and optional destructor can be set to be called when a thread exits.
+ *
+ * @param key
+ *   Pointer to store the allocated key.
+ * @param destructor
+ *   The function to be called when the thread exits.
+ *   Ignored on Windows OS.
+ *
+ * @return
+ *   On success, zero.
+ *   On failure, a negative number.
+ */
+
+__rte_experimental
+int rte_thread_tls_key_create(rte_tls_key *key, void (*destructor)(void *));
+
+/**
+ * Delete a TLS data key visible to all threads in the process.
+ *
+ * @param key
+ *   The key allocated by rte_thread_tls_key_create().
+ *
+ * @return
+ *   On success, zero.
+ *   On failure, a negative number.
+ */
+__rte_experimental
+int rte_thread_tls_key_delete(rte_tls_key key);
+
+/**
+ * Set value bound to the TLS key on behalf of the calling thread.
+ *
+ * @param key
+ *   The key allocated by rte_thread_tls_key_create().
+ * @param value
+ *   The value bound to the rte_tls_key key for the calling thread.
+ *
+ * @return
+ *   On success, zero.
+ *   On failure, a negative number.
+ */
+__rte_experimental
+int rte_thread_tls_value_set(rte_tls_key key, const void *value);
+
+/**
+ * Get value bound to the TLS key on behalf of the calling thread.
+ *
+ * @param key
+ *   The key allocated by rte_thread_tls_key_create().
+ *
+ * @return
+ *   On success, value data pointer (can also be NULL).
+ *   On failure, NULL and an error number is set in rte_errno.
+ */
+__rte_experimental
+void *rte_thread_tls_value_get(rte_tls_key key);
+
 #ifdef __cplusplus
 }
 #endif

lib/librte_eal/rte_eal_exports.def

@@ -322,6 +322,11 @@ EXPORTS
 	rte_vect_get_max_simd_bitwidth
 	rte_vect_set_max_simd_bitwidth
 
+	rte_thread_tls_key_create
+	rte_thread_tls_key_delete
+	rte_thread_tls_value_get
+	rte_thread_tls_value_set
+
 	rte_mem_lock
 	rte_mem_map
 	rte_mem_page_size

lib/librte_eal/unix/meson.build

@@ -5,4 +5,5 @@ sources += files(
 	'eal_file.c',
 	'eal_unix_memory.c',
 	'eal_unix_timer.c',
+	'rte_thread.c',
 )

lib/librte_eal/unix/rte_thread.c

@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2021 Mellanox Technologies, Ltd
+ */
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <rte_common.h>
+#include <rte_errno.h>
+#include <rte_log.h>
+#include <rte_thread.h>
+
+struct eal_tls_key {
+	pthread_key_t thread_index;
+};
+
+int
+rte_thread_tls_key_create(rte_tls_key *key, void (*destructor)(void *))
+{
+	int err;
+
+	*key = malloc(sizeof(**key));
+	if ((*key) == NULL) {
+		RTE_LOG(DEBUG, EAL, "Cannot allocate TLS key.\n");
+		return -1;
+	}
+	err = pthread_key_create(&((*key)->thread_index), destructor);
+	if (err) {
+		RTE_LOG(DEBUG, EAL, "pthread_key_create failed: %s\n",
+			 strerror(err));
+		free(*key);
+		return -1;
+	}
+	return 0;
+}
+
+int
+rte_thread_tls_key_delete(rte_tls_key key)
+{
+	int err;
+
+	if (!key) {
+		RTE_LOG(DEBUG, EAL, "Invalid TLS key.\n");
+		return -1;
+	}
+	err = pthread_key_delete(key->thread_index);
+	if (err) {
+		RTE_LOG(DEBUG, EAL, "pthread_key_delete failed: %s\n",
+			 strerror(err));
+		free(key);
+		return -1;
+	}
+	free(key);
+	return 0;
+}
+
+int
+rte_thread_tls_value_set(rte_tls_key key, const void *value)
+{
+	int err;
+
+	if (!key) {
+		RTE_LOG(DEBUG, EAL, "Invalid TLS key.\n");
+		return -1;
+	}
+	err = pthread_setspecific(key->thread_index, value);
+	if (err) {
+		RTE_LOG(DEBUG, EAL, "pthread_setspecific failed: %s\n",
+			strerror(err));
+		return -1;
+	}
+	return 0;
+}
+
+void *
+rte_thread_tls_value_get(rte_tls_key key)
+{
+	if (!key) {
+		RTE_LOG(DEBUG, EAL, "Invalid TLS key.\n");
+		rte_errno = EINVAL;
+		return NULL;
+	}
+	return pthread_getspecific(key->thread_index);
+}

lib/librte_eal/version.map

@@ -403,6 +403,12 @@ EXPERIMENTAL {
 	rte_service_lcore_may_be_active;
 	rte_vect_get_max_simd_bitwidth;
 	rte_vect_set_max_simd_bitwidth;
+
+	# added in 21.02
+	rte_thread_tls_key_create;
+	rte_thread_tls_key_delete;
+	rte_thread_tls_value_get;
+	rte_thread_tls_value_set;
 };
 
 INTERNAL {

lib/librte_eal/windows/meson.build

@@ -19,6 +19,7 @@ sources += files(
 	'eal_timer.c',
 	'fnmatch.c',
 	'getopt.c',
+	'rte_thread.c',
 )
 
 dpdk_conf.set10('RTE_EAL_NUMA_AWARE_HUGEPAGES', true)

lib/librte_eal/windows/rte_thread.c

@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright 2021 Mellanox Technologies, Ltd
+ */
+
+#include <rte_common.h>
+#include <rte_errno.h>
+#include <rte_thread.h>
+#include <rte_windows.h>
+
+struct eal_tls_key {
+	DWORD thread_index;
+};
+
+int
+rte_thread_tls_key_create(rte_tls_key *key,
+		__rte_unused void (*destructor)(void *))
+{
+	*key = malloc(sizeof(**key));
+	if ((*key) == NULL) {
+		RTE_LOG(DEBUG, EAL, "Cannot allocate TLS key.\n");
+		return -1;
+	}
+	(*key)->thread_index = TlsAlloc();
+	if ((*key)->thread_index == TLS_OUT_OF_INDEXES) {
+		RTE_LOG_WIN32_ERR("TlsAlloc()");
+		free(*key);
+		return -1;
+	}
+	return 0;
+}
+
+int
+rte_thread_tls_key_delete(rte_tls_key key)
+{
+	if (!key) {
+		RTE_LOG(DEBUG, EAL, "Invalid TLS key.\n");
+		return -1;
+	}
+	if (!TlsFree(key->thread_index)) {
+		RTE_LOG_WIN32_ERR("TlsFree()");
+		free(key);
+		return -1;
+	}
+	free(key);
+	return 0;
+}
+
+int
+rte_thread_tls_value_set(rte_tls_key key, const void *value)
+{
+	char *p;
+
+	if (!key) {
+		RTE_LOG(DEBUG, EAL, "Invalid TLS key.\n");
+		return -1;
+	}
+	/* discard const qualifier */
+	p = (char *) (uintptr_t) value;
+	if (!TlsSetValue(key->thread_index, p)) {
+		RTE_LOG_WIN32_ERR("TlsSetValue()");
+		return -1;
+	}
+	return 0;
+}
+
+void *
+rte_thread_tls_value_get(rte_tls_key key)
+{
+	void *output;
+
+	if (!key) {
+		RTE_LOG(DEBUG, EAL, "Invalid TLS key.\n");
+		rte_errno = EINVAL;
+		return NULL;
+	}
+	output = TlsGetValue(key->thread_index);
+	if (GetLastError() != ERROR_SUCCESS) {
+		RTE_LOG_WIN32_ERR("TlsGetValue()");
+		rte_errno = ENOEXEC;
+		return NULL;
+	}
+	return output;
+}