Move to kernel style SPDX license identifiers

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

diff --git a/liblttng-ust/lttng-context-vpid.c b/liblttng-ust/lttng-context-vpid.c
index 5e5ed145d944adf08be61755eaa32faefe3e52b4..d4b4a2cf9da81414f949f584d2d9cc1bb65fda23 100644 (file)
--- a/liblttng-ust/lttng-context-vpid.c
+++ b/liblttng-ust/lttng-context-vpid.c
@@ -1,43 +1,19 @@
 /*
- * lttng-context-vpid.c
- *
- * LTTng UST vpid 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 vpid 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>
 
-#ifdef __linux__
-static inline
-pid_t wrapper_getpid(void)
-{
-       return getpid();
-}
-
-void lttng_context_vpid_reset(void)
-{
-}
-#else
 /*
  * We cache the result to ensure we don't trigger a system call for
  * each event.
@@ -45,11 +21,16 @@ void lttng_context_vpid_reset(void)
 static pid_t cached_vpid;
 
 static inline
-pid_t wrapper_getpid(void)
+pid_t wrapper_getvpid(void)
 {
-       if (caa_unlikely(!cached_vpid))
-               cached_vpid = getpid();
-       return cached_vpid;
+       pid_t vpid;
+
+       vpid = CMM_LOAD_SHARED(cached_vpid);
+       if (caa_unlikely(!vpid)) {
+               vpid = getpid();
+               CMM_STORE_SHARED(cached_vpid, vpid);
+       }
+       return vpid;
 }
 
 /*
@@ -58,9 +39,8 @@ pid_t wrapper_getpid(void)
  */
 void lttng_context_vpid_reset(void)
 {
-       cached_vpid = 0;
+       CMM_STORE_SHARED(cached_vpid, 0);
 }
-#endif
 
 static
 size_t vpid_get_size(struct lttng_ctx_field *field, size_t offset)
@@ -77,21 +57,17 @@ void vpid_record(struct lttng_ctx_field *field,
                 struct lttng_ust_lib_ring_buffer_ctx *ctx,
                 struct lttng_channel *chan)
 {
-       pid_t pid;
+       pid_t vpid = wrapper_getvpid();
 
-       pid = wrapper_getpid();
-       lib_ring_buffer_align_ctx(ctx, lttng_alignof(pid));
-       chan->ops->event_write(ctx, &pid, sizeof(pid));
+       lib_ring_buffer_align_ctx(ctx, lttng_alignof(vpid));
+       chan->ops->event_write(ctx, &vpid, sizeof(vpid));
 }
 
 static
 void vpid_get_value(struct lttng_ctx_field *field,
                struct lttng_ctx_value *value)
 {
-       pid_t pid;
-
-       pid = wrapper_getpid();
-       value->u.s64 = pid;
+       value->u.s64 = wrapper_getvpid();
 }
 
 int lttng_add_vpid_to_ctx(struct lttng_ctx **ctx)
@@ -107,12 +83,12 @@ int lttng_add_vpid_to_ctx(struct lttng_ctx **ctx)
        }
        field->event_field.name = "vpid";
        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 = vpid_get_size;
        field->record = vpid_record;
        field->get_value = vpid_get_value;