Add context management infrastructure

[lttng-modules.git] / ltt-context.c

diff --git a/ltt-context.c b/ltt-context.c
new file mode 100644 (file)
index 0000000..cc9633a
--- /dev/null
+++ b/ltt-context.c
@@ -0,0 +1,54 @@
+/*
+ * ltt-context.c
+ *
+ * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * LTTng trace/channel/event context management.
+ */
+
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include "wrapper/vmalloc.h"   /* for wrapper_vmalloc_sync_all() */
+#include "ltt-events.h"
+#include "ltt-tracer.h"
+
+struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
+{
+       struct lttng_ctx_field *field;
+       struct lttng_ctx *ctx;
+
+       if (!*ctx_p) {
+               *ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
+               if (!*ctx_p)
+                       return NULL;
+       }
+       ctx = *ctx_p;
+       if (ctx->nr_fields + 1 > ctx->allocated_fields) {
+               struct lttng_ctx_field *new_fields;
+
+               ctx->allocated_fields = min_t(size_t, 1, 2 * ctx->allocated_fields);
+               new_fields = kzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL);
+               if (!new_fields)
+                       return NULL;
+               if (ctx->fields)
+                       memcpy(new_fields, ctx->fields, ctx->nr_fields);
+               kfree(ctx->fields);
+               ctx->fields = new_fields;
+       }
+       field = &ctx->fields[ctx->nr_fields];
+       ctx->nr_fields++;
+       return field;
+}
+EXPORT_SYMBOL_GPL(lttng_append_context);
+
+void lttng_destroy_context(struct lttng_ctx *ctx)
+{
+       int i;
+
+       for (i = 0; i < ctx->nr_fields; i++)
+               ctx->fields[i].destroy(&ctx->fields[i]);
+       kfree(ctx->fields);
+       kfree(ctx);
+}