Commit e1640949 authored Feb 19, 2008 by Jens Axboe

elevator: make elevator_get() attempt to load the appropriate module



Currently we fail if someone requests a valid io scheduler, but it's
modular and not currently loaded. That can happen from a driver init
asking for a different scheduler, or online switching through sysfs
as requested by a user.

This patch makes elevator_get() request_module() to attempt to load
the appropriate module, instead of requiring that done manually.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

parent ffc4e759

block/elevator.c

+15 −0

Original line number	Diff line number	Diff line
		@@ -134,6 +134,21 @@ static struct elevator_type elevator_get(const char name)
		spin_lock(&elv_list_lock);

		e = elevator_find(name);
		if (!e) {
		char elv[ELV_NAME_MAX + strlen("-iosched")];

		spin_unlock(&elv_list_lock);

		if (!strcmp(name, "anticipatory"))
		sprintf(elv, "as-iosched");
		else
		sprintf(elv, "%s-iosched", name);

		request_module(elv);
		spin_lock(&elv_list_lock);
		e = elevator_find(name);
		}

		if (e && !try_module_get(e->elevator_owner))
		e = NULL;