4.14-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 2527d99789e248576ac8081530cd4fd88730f8c7 ]
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 Reviewed-by: Omar Sandoval osandov@fb.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/elevator.c | 44 +++++++++++++++++++++----------------------- 1 file changed, 21 insertions(+), 23 deletions(-)
diff --git a/block/elevator.c b/block/elevator.c index 153926a90901..8320d97240be 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -83,12 +83,15 @@ 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) +/* + * Return scheduler with name 'name' and with matching 'mq capability + */ +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 +103,25 @@ 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 +147,12 @@ void __init load_default_elevator_module(void) if (!chosen_elevator[0]) return;
+ /* + * Boot parameter is deprecated, we haven't supported that for MQ. + * 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 +209,7 @@ 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 +221,7 @@ 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 +236,17 @@ 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 +912,7 @@ 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 +1073,7 @@ 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;
@@ -1076,15 +1083,6 @@ static int __elevator_change(struct request_queue *q, const char *name) return 0; }
- if (!e->uses_mq && q->mq_ops) { - elevator_put(e); - return -EINVAL; - } - if (e->uses_mq && !q->mq_ops) { - elevator_put(e); - return -EINVAL; - } - return elevator_switch(q, e); }