If an IO scheduler is selected via elevator= and it doesn't match the driver in question wrt blk-mq support, then we fail to boot.
The elevator= parameter is deprecated and only supported for non-mq devices. Augment the elevator lookup API so that we pass in if we're looking for an mq capable scheduler or not, so that we only ever return a valid type for the queue in question. Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=196695 Signed-off-by: Jens Axboe <ax...@kernel.dk> diff --git a/block/elevator.c b/block/elevator.c index 153926a90901..318cf00ea213 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -83,12 +83,13 @@ bool elv_bio_merge_ok(struct request *rq, struct bio *bio) } EXPORT_SYMBOL(elv_bio_merge_ok); -static struct elevator_type *elevator_find(const char *name) +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)) + if (!strcmp(e->elevator_name, name) && + !(mq ^ e->uses_mq)) return e; } @@ -100,25 +101,25 @@ static void elevator_put(struct elevator_type *e) module_put(e->elevator_owner); } -static struct elevator_type *elevator_get(const char *name, bool try_loading) +static struct elevator_type *elevator_get(struct request_queue *q, + const char *name, bool try_loading) { struct elevator_type *e; spin_lock(&elv_list_lock); - e = elevator_find(name); + e = elevator_find(name, q->mq_ops != NULL); if (!e && try_loading) { spin_unlock(&elv_list_lock); request_module("%s-iosched", name); spin_lock(&elv_list_lock); - e = elevator_find(name); + e = elevator_find(name, q->mq_ops != NULL); } if (e && !try_module_get(e->elevator_owner)) e = NULL; spin_unlock(&elv_list_lock); - return e; } @@ -144,8 +145,12 @@ void __init load_default_elevator_module(void) if (!chosen_elevator[0]) return; + /* + * Boot parameter is deprecated, we haven't supported that for MQ + * so only look for non-mq schedulers from here. + */ spin_lock(&elv_list_lock); - e = elevator_find(chosen_elevator); + e = elevator_find(chosen_elevator, false); spin_unlock(&elv_list_lock); if (!e) @@ -202,7 +207,7 @@ int elevator_init(struct request_queue *q, char *name) q->boundary_rq = NULL; if (name) { - e = elevator_get(name, true); + e = elevator_get(q, name, true); if (!e) return -EINVAL; } @@ -214,7 +219,7 @@ int elevator_init(struct request_queue *q, char *name) * allowed from async. */ if (!e && !q->mq_ops && *chosen_elevator) { - e = elevator_get(chosen_elevator, false); + e = elevator_get(q, chosen_elevator, false); if (!e) printk(KERN_ERR "I/O scheduler %s not found\n", chosen_elevator); @@ -229,17 +234,17 @@ int elevator_init(struct request_queue *q, char *name) */ if (q->mq_ops) { if (q->nr_hw_queues == 1) - e = elevator_get("mq-deadline", false); + e = elevator_get(q, "mq-deadline", false); if (!e) return 0; } else - e = elevator_get(CONFIG_DEFAULT_IOSCHED, false); + e = elevator_get(q, CONFIG_DEFAULT_IOSCHED, false); if (!e) { printk(KERN_ERR "Default I/O scheduler not found. " \ "Using noop.\n"); - e = elevator_get("noop", false); + e = elevator_get(q, "noop", false); } } @@ -905,7 +910,7 @@ int elv_register(struct elevator_type *e) /* register, don't allow duplicate names */ spin_lock(&elv_list_lock); - if (elevator_find(e->elevator_name)) { + if (elevator_find(e->elevator_name, e->uses_mq)) { spin_unlock(&elv_list_lock); if (e->icq_cache) kmem_cache_destroy(e->icq_cache); @@ -1066,7 +1071,7 @@ static int __elevator_change(struct request_queue *q, const char *name) return elevator_switch(q, NULL); strlcpy(elevator_name, name, sizeof(elevator_name)); - e = elevator_get(strstrip(elevator_name), true); + e = elevator_get(q, strstrip(elevator_name), true); if (!e) return -EINVAL;
