context: document and check that only last context is removed

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

diff --git a/ltt-context.c b/ltt-context.c
index 6c3890c3e4a7ba46d2c6f320610a069edbf7dbcd..154e9966e861073e694bd9e95bb21368d90cefa2 100644 (file)
--- a/ltt-context.c
+++ b/ltt-context.c
@@ -21,6 +21,9 @@ int lttng_find_context(struct lttng_ctx *ctx, const char *name)
        unsigned int i;
 
        for (i = 0; i < ctx->nr_fields; i++) {
+               /* Skip allocated (but non-initialized) contexts */
+               if (!ctx->fields[i].event_field.name)
+                       continue;
                if (!strcmp(ctx->fields[i].event_field.name, name))
                        return 1;
        }
@@ -57,6 +60,9 @@ struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
 }
 EXPORT_SYMBOL_GPL(lttng_append_context);
 
+/*
+ * Remove last context field.
+ */
 void lttng_remove_context_field(struct lttng_ctx **ctx_p,
                                struct lttng_ctx_field *field)
 {
@@ -64,6 +70,7 @@ void lttng_remove_context_field(struct lttng_ctx **ctx_p,
 
        ctx = *ctx_p;
        ctx->nr_fields--;
+       WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field);
        memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
 }
 EXPORT_SYMBOL_GPL(lttng_remove_context_field);