Move to kernel style SPDX license identifiers

[lttng-ust.git] / liblttng-ust / lttng-context-vtid.c

diff --git a/liblttng-ust/lttng-context-vtid.c b/liblttng-ust/lttng-context-vtid.c
index d5664c951cf708ff2b7ac6e9be4ca3b61fbbe87b..feb253d08b6d57c69f37d01be5cb2917345c1f0a 100644 (file)
--- a/liblttng-ust/lttng-context-vtid.c
+++ b/liblttng-ust/lttng-context-vtid.c
@@ -1,56 +1,27 @@
 /*
- * lttng-context-vtid.c
- *
- * LTTng UST vtid context.
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
  * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ * LTTng UST vtid context.
  */
 
+#define _LGPL_SOURCE
+#include <stddef.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <lttng/ust-events.h>
 #include <lttng/ust-tracer.h>
 #include <lttng/ringbuffer-config.h>
-#include "ltt-tracer-core.h"
-
-#ifdef __linux__
-#include <syscall.h>
-#endif
-
-#if defined(_syscall0)
-_syscall0(pid_t, gettid)
-#elif defined(__NR_gettid)
-static inline pid_t gettid(void)
-{
-       return syscall(__NR_gettid);
-}
-#else
-#warning "use pid as tid"
-static inline pid_t gettid(void)
-{
-       return getpid();
-}
-#endif
+#include <lttng/ust-tid.h>
+#include <urcu/tls-compat.h>
+#include "lttng-tracer-core.h"
 
 /*
  * We cache the result to ensure we don't trigger a system call for
  * each event.
  */
-static __thread pid_t cached_vtid;
+static DEFINE_URCU_TLS(pid_t, cached_vtid);
 
 /*
  * Upon fork or clone, the TID assigned to our thread is not the same as
@@ -59,11 +30,11 @@ static __thread pid_t cached_vtid;
  */
 void lttng_context_vtid_reset(void)
 {
-       cached_vtid = 0;
+       CMM_STORE_SHARED(URCU_TLS(cached_vtid), 0);
 }
 
 static
-size_t vtid_get_size(size_t offset)
+size_t vtid_get_size(struct lttng_ctx_field *field, size_t offset)
 {
        size_t size = 0;
 
@@ -72,15 +43,35 @@ size_t vtid_get_size(size_t offset)
        return size;
 }
 
+static inline
+pid_t wrapper_getvtid(void)
+{
+       pid_t vtid;
+
+       vtid = CMM_LOAD_SHARED(URCU_TLS(cached_vtid));
+       if (caa_unlikely(!vtid)) {
+               vtid = lttng_gettid();
+               CMM_STORE_SHARED(URCU_TLS(cached_vtid), vtid);
+       }
+       return vtid;
+}
+
 static
 void vtid_record(struct lttng_ctx_field *field,
                 struct lttng_ust_lib_ring_buffer_ctx *ctx,
-                struct ltt_channel *chan)
+                struct lttng_channel *chan)
+{
+       pid_t vtid = wrapper_getvtid();
+
+       lib_ring_buffer_align_ctx(ctx, lttng_alignof(vtid));
+       chan->ops->event_write(ctx, &vtid, sizeof(vtid));
+}
+
+static
+void vtid_get_value(struct lttng_ctx_field *field,
+               struct lttng_ctx_value *value)
 {
-       if (caa_unlikely(!cached_vtid))
-               cached_vtid = gettid();
-       lib_ring_buffer_align_ctx(ctx, lttng_alignof(cached_vtid));
-       chan->ops->event_write(ctx, &cached_vtid, sizeof(cached_vtid));
+       value->u.s64 = wrapper_getvtid();
 }
 
 int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
@@ -96,14 +87,16 @@ int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
        }
        field->event_field.name = "vtid";
        field->event_field.type.atype = atype_integer;
-       field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
-       field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
-       field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
-       field->event_field.type.u.basic.integer.reverse_byte_order = 0;
-       field->event_field.type.u.basic.integer.base = 10;
-       field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
+       field->event_field.type.u.integer.size = sizeof(pid_t) * CHAR_BIT;
+       field->event_field.type.u.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
+       field->event_field.type.u.integer.signedness = lttng_is_signed_type(pid_t);
+       field->event_field.type.u.integer.reverse_byte_order = 0;
+       field->event_field.type.u.integer.base = 10;
+       field->event_field.type.u.integer.encoding = lttng_encode_none;
        field->get_size = vtid_get_size;
        field->record = vtid_record;
+       field->get_value = vtid_get_value;
+       lttng_context_update(*ctx);
        return 0;
 }
 
@@ -112,5 +105,5 @@ int lttng_add_vtid_to_ctx(struct lttng_ctx **ctx)
  */
 void lttng_fixup_vtid_tls(void)
 {
-       asm volatile ("" : : "m" (cached_vtid));
+       asm volatile ("" : : "m" (URCU_TLS(cached_vtid)));
 }