From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B6F92857F1 for ; Thu, 10 Apr 2025 13:31:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744291909; cv=none; b=Pkyy9WflBOagjFeGQqTI/FqedkUUD9V8EvI33sQUbHw5XU1ZTjtt3yNtJvUilLOqcxq+qsb3O/zhz3mq9hCsYiJWswmSLkdfLuV0Lv/kNeeeXGdX4LhBD9GSkkV6oaryi3pAHKf7A73ComJv2NE38r6UMAeSeT+a/+Bi2bCDh+w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744291909; c=relaxed/simple; bh=sQzBRb6djE14fXxwyoanIqkwnJlxILhasCQNJ3/imu4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=R1vmmCcFSonCKX2Y0HgGgVXGD7kC6wRLKn5z6jvr11S3rbTKYCSekSjnMoJ+n51TQOCAxWeTdCjpQ6LGc2TTI/BibFkYJEElmGyyLf2RABac65hC+L5akWSU7Tl5ENY7S9BEsMFkljJYXJ8jEoT7indEajlpOSFfJq94nFBdLp4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=GDe0wmkJ; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GDe0wmkJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744291907; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=a29raZsIKbstEY4RZDUaY5m2siILLtua0KYgV7Zwkfs=; b=GDe0wmkJEu6mBhr9nm9zm4bM2FW53QI1Sa7EoKilQYJCAXEPUzLfseGiSxiv5k+H5lteZh X0M0Rsv+pUFnurRt54CaZ9rZnsxEDrhOgnZxTvdq3Bx8INStMSCwWRpk7xv+WyQ0+Zf76A Njjt3o69UZUyfoZVeWjUWxKeaV19eiA= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-532-rXAxqA58PsOpBQxGmTj_Tg-1; Thu, 10 Apr 2025 09:31:43 -0400 X-MC-Unique: rXAxqA58PsOpBQxGmTj_Tg-1 X-Mimecast-MFC-AGG-ID: rXAxqA58PsOpBQxGmTj_Tg_1744291901 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7E6061800361; Thu, 10 Apr 2025 13:31:41 +0000 (UTC) Received: from localhost (unknown [10.72.120.20]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 880D5180174E; Thu, 10 Apr 2025 13:31:40 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org Cc: Nilay Shroff , Shinichiro Kawasaki , =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Christoph Hellwig , Ming Lei Subject: [PATCH 11/15] block: move elv_register[unregister]_queue out of elevator_lock Date: Thu, 10 Apr 2025 21:30:23 +0800 Message-ID: <20250410133029.2487054-12-ming.lei@redhat.com> In-Reply-To: <20250410133029.2487054-1-ming.lei@redhat.com> References: <20250410133029.2487054-1-ming.lei@redhat.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Move elv_register[unregister]_queue out of ->elevator_lock & queue freezing, so we can kill many lockdep warnings. elv_register[unregister]_queue() is serialized, and just dealing with sysfs/debugfs things, no need to be done with queue frozen. Signed-off-by: Ming Lei --- block/blk-mq.c | 9 ++++---- block/blk.h | 1 + block/elevator.c | 58 ++++++++++++++++++++++++++++++++++-------------- block/elevator.h | 5 +++++ 4 files changed, 52 insertions(+), 21 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 608a74e3a87c..7219b01764da 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4990,16 +4990,17 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, .force = 1, .uevent = 1, }; + int ret = -ENODEV; mutex_lock(&q->elevator_lock); if (q->elevator && !blk_queue_dying(q)) ctx.name = q->elevator->type->elevator_name; - __elevator_change(q, &ctx); + ret = __elevator_change(q, &ctx); mutex_unlock(&q->elevator_lock); - } - - list_for_each_entry(q, &set->tag_list, tag_set_list) blk_mq_unfreeze_queue_nomemrestore(q); + if (!ret) + WARN_ON_ONCE(elevator_change_done(q, &ctx)); + } memalloc_noio_restore(memflags); /* Free the excess tags when nr_hw_queues shrink. */ diff --git a/block/blk.h b/block/blk.h index 4626beedfdce..634cebd7a7b4 100644 --- a/block/blk.h +++ b/block/blk.h @@ -321,6 +321,7 @@ bool blk_bio_list_merge(struct request_queue *q, struct list_head *list, bool blk_insert_flush(struct request *rq); int __elevator_change(struct request_queue *q, struct elev_change_ctx *ctx); +int elevator_change_done(struct request_queue *q, struct elev_change_ctx *ctx); void elevator_set_default(struct request_queue *q); void elevator_set_none(struct request_queue *q); diff --git a/block/elevator.c b/block/elevator.c index 238b8d47cc2b..1cc640a9db3e 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -151,18 +151,24 @@ static void elevator_release(struct kobject *kobj) kfree(e); } -static void elevator_exit(struct request_queue *q) +static void __elevator_exit(struct request_queue *q) { struct elevator_queue *e = q->elevator; + lockdep_assert_held(&q->elevator_lock); + ioc_clear_queue(q); blk_mq_sched_free_rqs(q); mutex_lock(&e->sysfs_lock); blk_mq_exit_sched(q, e); mutex_unlock(&e->sysfs_lock); +} - kobject_put(&e->kobj); +static void elevator_exit(struct request_queue *q) +{ + __elevator_exit(q); + kobject_put(&q->elevator->kobj); } static inline void __elv_rqhash_del(struct request *rq) @@ -461,8 +467,6 @@ static int elv_register_queue(struct request_queue *q, { int error; - lockdep_assert_held(&q->elevator_lock); - if (test_bit(ELEVATOR_FLAG_REGISTERED, &e->flags)) return 0; @@ -488,8 +492,6 @@ static int elv_register_queue(struct request_queue *q, static void elv_unregister_queue(struct request_queue *q, struct elevator_queue *e) { - lockdep_assert_held(&q->elevator_lock); - if (e && test_and_clear_bit(ELEVATOR_FLAG_REGISTERED, &e->flags)) { kobject_uevent(&e->kobj, KOBJ_REMOVE); kobject_del(&e->kobj); @@ -629,19 +631,15 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e, blk_mq_quiesce_queue(q); if (q->elevator) { - elv_unregister_queue(q, q->elevator); - elevator_exit(q); + ctx->old = q->elevator; + __elevator_exit(q); } ret = blk_mq_init_sched(q, new_e); if (ret) goto out_unfreeze; - ret = elv_register_queue(q, q->elevator, ctx->uevent); - if (ret) { - elevator_exit(q); - goto out_unfreeze; - } + ctx->new = q->elevator; blk_add_trace_msg(q, "elv switch: %s", new_e->elevator_name); out_unfreeze: @@ -655,15 +653,16 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e, return ret; } -static void elevator_disable(struct request_queue *q) +static void elevator_disable(struct request_queue *q, + struct elev_change_ctx *ctx) { WARN_ON_ONCE(q->mq_freeze_depth == 0); lockdep_assert_held(&q->elevator_lock); blk_mq_quiesce_queue(q); - elv_unregister_queue(q, q->elevator); - elevator_exit(q); + ctx->old = q->elevator; + __elevator_exit(q); blk_queue_flag_clear(QUEUE_FLAG_SQ_SCHED, q); q->elevator = NULL; q->nr_requests = q->tag_set->queue_depth; @@ -672,6 +671,28 @@ static void elevator_disable(struct request_queue *q) blk_mq_unquiesce_queue(q); } +int elevator_change_done(struct request_queue *q, struct elev_change_ctx *ctx) +{ + int ret = 0; + + if (ctx->old) { + elv_unregister_queue(q, ctx->old); + kobject_put(&ctx->old->kobj); + } + if (ctx->new) { + ret = elv_register_queue(q, ctx->new, ctx->uevent); + if (ret) { + unsigned memflags = blk_mq_freeze_queue(q); + + mutex_lock(&q->elevator_lock); + elevator_exit(q); + mutex_unlock(&q->elevator_lock); + blk_mq_unfreeze_queue(q, memflags); + } + } + return 0; +} + /* * Switch this queue to the given IO scheduler. */ @@ -683,7 +704,7 @@ int __elevator_change(struct request_queue *q, struct elev_change_ctx *ctx) if (!strncmp(elevator_name, "none", 4)) { if (q->elevator) - elevator_disable(q); + elevator_disable(q, ctx); return 0; } @@ -728,6 +749,9 @@ static int elevator_change(struct request_queue *q, ret = __elevator_change(q, ctx); mutex_unlock(&q->elevator_lock); blk_mq_unfreeze_queue(q, memflags); + if (!ret) + ret = elevator_change_done(q, ctx); + exit: srcu_read_unlock(&set->update_nr_hwq_srcu, idx); return ret; diff --git a/block/elevator.h b/block/elevator.h index 86b4977cf772..87848fdc8a52 100644 --- a/block/elevator.h +++ b/block/elevator.h @@ -128,6 +128,11 @@ struct elev_change_ctx { const char *name; unsigned int force:1; unsigned int uevent:1; + + /* for unregistering old elevator */ + struct elevator_queue *old; + /* for registering new elevator */ + struct elevator_queue *new; }; /* -- 2.47.0