discover: Make boot_priorities more flexible

Rather than rely on the ordering of the boot_priorities array to define
which device types have a higher "default boot" priority, this change
introduces a slightly more flexible way of priority lookups, by adding a
separate priority field to struct boot_priority.

This means we can have an unordered array, change priorities without
re-writing the array, and implementing a disable mechanism.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 13 insertions, 5 deletions

diff --git a/discover/device-handler.c b/discover/device-handler.c
index c57b7b6..a271390 100644
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -386,28 +386,36 @@ static int default_option_priority(struct discover_boot_option *opt)
 	for (i = 0; i < config->n_boot_priorities; i++) {
 		prio = &config->boot_priorities[i];
 		if (priority_match(prio, opt))
-			break;
+			return prio->priority;
 	}
 
-	return i;
+	return 0;
 }
 
 static void set_default(struct device_handler *handler,
 		struct discover_boot_option *opt)
 {
+	int new_prio;
+
 	if (!handler->autoboot_enabled)
 		return;
 
+	new_prio = default_option_priority(opt);
+
+	/* A negative priority indicates that we don't want to boot this device
+	 * by default */
+	if (new_prio < 0)
+		return;
+
 	/* Resolve any conflicts: if we have a new default option, it only
 	 * replaces the current if it has a higher priority. */
 	if (handler->default_boot_option) {
-		int new_prio, cur_prio;
+		int cur_prio;
 
-		new_prio = default_option_priority(opt);
 		cur_prio = default_option_priority(
 					handler->default_boot_option);
 
-		if (new_prio < cur_prio) {
+		if (new_prio > cur_prio) {
 			handler->default_boot_option = opt;
 			/* extend the timeout a little, so the user sees some
 			 * indication of the change */