Mathieu Poirier [off-list ref] writes:

+enum {
+	ETM_TOKEN_SINK_CPU,
+	ETM_TOKEN_SINK,
+	ETM_TOKEN_ERR,
+};
+
+static const match_table_t drv_cfg_tokens = {
+	{ETM_TOKEN_SINK_CPU, "sink=cpu%d:%s"},
+	{ETM_TOKEN_SINK, "sink=%s"},
+	{ETM_TOKEN_ERR, NULL},
+};

Wait, but we just parsed away the '=' and the whole thing is now a
linked list of { key, value }?

This also answers my question from the other email about the use cases
for sending in ascii strings. In my opinion, all this is completely
unnecessary.

+static int
+etm_set_drv_configs(struct perf_event *event,
+		    struct list_head *drv_configs)
+{
+	char *config, *sink;
+	int len;
+	struct perf_drv_config *drv_config;
+	void *old_sink;
+
+	list_for_each_entry(drv_config, drv_configs, entry) {
+		/* ETM HW configuration needs a sink specification */
+		if (!drv_config->option)
+			return -EINVAL;
+
+		len = strlen(drv_config->config) + strlen("=") +
+		      strlen(drv_config->option) + 1;
+
+		config = kmalloc(len, GFP_KERNEL);
+		if (!config)
+			return -ENOMEM;
+
+		/* Reconstruct user configuration */
+		snprintf(config, len, "%s=%s",
+			 drv_config->config, drv_config->option);

Wait, what? We parse this *twice*?

There's basically a malloc+snprintf[which could have been
kasprintf()]+match_token just to see if drv_config::option starts with a
'cpu%d:'?

Regards,
--
Alex