From 3a5088c8c11ac9d56f7e90acaaae9e0e98c1ff94 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sat, 15 Apr 2017 20:38:22 +0800 Subject: [PATCH] block: respect BLK_MQ_F_NO_SCHED If one driver claims that it doesn't support io scheduler via BLK_MQ_F_NO_SCHED, we should not allow to change and show the availabe io schedulers. This patch adds check to enhance this behaviour. Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/elevator.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/block/elevator.c b/block/elevator.c index dbeecf7be719..4d9084a14c10 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -1098,12 +1098,20 @@ int elevator_change(struct request_queue *q, const char *name) } EXPORT_SYMBOL(elevator_change); +static inline bool elv_support_iosched(struct request_queue *q) +{ + if (q->mq_ops && q->tag_set && (q->tag_set->flags & + BLK_MQ_F_NO_SCHED)) + return false; + return true; +} + ssize_t elv_iosched_store(struct request_queue *q, const char *name, size_t count) { int ret; - if (!(q->mq_ops || q->request_fn)) + if (!(q->mq_ops || q->request_fn) || !elv_support_iosched(q)) return count; ret = __elevator_change(q, name); @@ -1135,7 +1143,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name) len += sprintf(name+len, "[%s] ", elv->elevator_name); continue; } - if (__e->uses_mq && q->mq_ops) + if (__e->uses_mq && q->mq_ops && elv_support_iosched(q)) len += sprintf(name+len, "%s ", __e->elevator_name); else if (!__e->uses_mq && !q->mq_ops) len += sprintf(name+len, "%s ", __e->elevator_name); -- 2.20.1