[PATCH 2/3] elevator: allow name aliases
From: Jens Axboe <axboe@kernel.dk>
Date: 2017-10-25 18:04:46
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Since we now lookup elevator types with the appropriate multiqueue capability, allow schedulers to register with an alias alongside the real name. This is in preparation for allowing 'mq-deadline' to register an alias of 'deadline' as well. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- block/elevator.c | 22 ++++++++++++++++------ include/linux/elevator.h | 1 + 2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/block/elevator.c b/block/elevator.c
index b70e69f795db..dc0432e12ecf 100644
--- a/block/elevator.c
+++ b/block/elevator.c@@ -83,6 +83,16 @@ bool elv_bio_merge_ok(struct request *rq, struct bio *bio) } EXPORT_SYMBOL(elv_bio_merge_ok); +static bool elevator_match(const struct elevator_type *e, const char *name) +{ + if (!strcmp(e->elevator_name, name)) + return true; + if (e->elevator_alias && !strcmp(e->elevator_alias, name)) + return true; + + return false; +} + /* * Return scheduler with name 'name' and with matching 'mq capability */
@@ -91,7 +101,7 @@ static struct elevator_type *elevator_find(const char *name, bool mq) struct elevator_type *e; list_for_each_entry(e, &elv_list, list) { - if (!strcmp(e->elevator_name, name) && !(mq ^ e->uses_mq)) + if (elevator_match(e, name) && !(mq ^ e->uses_mq)) return e; }
@@ -922,9 +932,9 @@ int elv_register(struct elevator_type *e) spin_unlock(&elv_list_lock); /* print pretty message */ - if (!strcmp(e->elevator_name, chosen_elevator) || + if (elevator_match(e, chosen_elevator) || (!*chosen_elevator && - !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED))) + elevator_match(e, CONFIG_DEFAULT_IOSCHED))) def = " (default)"; printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name,
@@ -1077,8 +1087,7 @@ static int __elevator_change(struct request_queue *q, const char *name) if (!e) return -EINVAL; - if (q->elevator && - !strcmp(elevator_name, q->elevator->type->elevator_name)) { + if (q->elevator && elevator_match(q->elevator->type, elevator_name)) { elevator_put(e); return 0; }
@@ -1126,7 +1135,8 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name) spin_lock(&elv_list_lock); list_for_each_entry(__e, &elv_list, list) { - if (elv && !strcmp(elv->elevator_name, __e->elevator_name)) { + if (elv && elevator_match(elv, __e->elevator_name) && + !(__e->uses_mq ^ (q->mq_ops != NULL))) { len += sprintf(name+len, "[%s] ", elv->elevator_name); continue; }
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 5bc8f8682a3e..6df8b14f1f6a 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h@@ -144,6 +144,7 @@ struct elevator_type size_t icq_align; /* ditto */ struct elv_fs_entry *elevator_attrs; char elevator_name[ELV_NAME_MAX]; + const char *elevator_alias; struct module *elevator_owner; bool uses_mq; #ifdef CONFIG_BLK_DEBUG_FS
--
2.7.4