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>
This commit is contained in:
Jens Axboe 2008-02-19 10:20:37 +01:00
parent ffc4e75957
commit e164094964

View File

@ -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;