From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 73DF41DF75D for ; Thu, 24 Apr 2025 15:23:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745508203; cv=none; b=EcvnbTOgxOx+P7SOreJmEkSr7MzPOEs2Vkf2/HqCDAoSubM9cYOMWKAqxSdSpbNFMMGTXW4pS408qIVeRCRS/Rk935QLT+WcDNbwcf1lk9FzFpVwNJ7YUVj7ATrjIqNS0KBGDxGgPqz79bFhY3QvVtXwagNrJvmOpw7SDFlxp2I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745508203; c=relaxed/simple; bh=CdQ2VssGJBG6l2mHIOI8JtRiHjuL3OPGUlfwLpsa28U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pSjNi+cRYzeqxnCJtElHt8lfPWW5A30zTDt4fn9Iz8vfjrsY+KfDjwMnaLQcBWIl+fL3RkV+pRreaC2aL8ecAN0pV4qBCOotnV8rYuVj/VmKCyv8VuMCcTjtocwYO/JAvl8xvxBMcCdEMKkc1pEPyBY88xsXkmIBeVHFbsUNdfU= 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=BQrwM4VC; arc=none smtp.client-ip=170.10.129.124 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="BQrwM4VC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1745508200; 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=37CnyDU3q9aG+5f5YH+duQgJEgHs+rA6GNO8gKYkyU0=; b=BQrwM4VCjhyJ6d/iodMs+/c5U6zyxjKkc3GaoWlKyYWTAkotBzlGMssn5KGCeHtGHW9JDg mkW53EWfYaQYFsxVjFbP17c645POXp5hzJBmY4pGcxdwOLrzp2qokWwjP3r2yRXIwweqih oTtsJtx5VwOJ3Dvna2a1eze+ZdvXHqo= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-451-gEx688iDNqi2EbwEzhJ1rg-1; Thu, 24 Apr 2025 11:23:15 -0400 X-MC-Unique: gEx688iDNqi2EbwEzhJ1rg-1 X-Mimecast-MFC-AGG-ID: gEx688iDNqi2EbwEzhJ1rg_1745508194 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6D64E19560BB; Thu, 24 Apr 2025 15:23:14 +0000 (UTC) Received: from localhost (unknown [10.72.116.90]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 4E3B719560A3; Thu, 24 Apr 2025 15:23:12 +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 V3 20/20] block: move wbt_enable_default() out of queue freezing from sched ->exit() Date: Thu, 24 Apr 2025 23:21:43 +0800 Message-ID: <20250424152148.1066220-21-ming.lei@redhat.com> In-Reply-To: <20250424152148.1066220-1-ming.lei@redhat.com> References: <20250424152148.1066220-1-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 3.0 on 10.30.177.12 scheduler's ->exit() is called with queue frozen and elevator lock is held, and wbt_enable_default() can't be called with queue frozen, otherwise the following lockdep warning is triggered: #6 (&q->rq_qos_mutex){+.+.}-{4:4}: #5 (&eq->sysfs_lock){+.+.}-{4:4}: #4 (&q->elevator_lock){+.+.}-{4:4}: #3 (&q->q_usage_counter(io)#3){++++}-{0:0}: #2 (fs_reclaim){+.+.}-{0:0}: #1 (&sb->s_type->i_mutex_key#3){+.+.}-{4:4}: #0 (&q->debugfs_mutex){+.+.}-{4:4}: Fix the issue by moving wbt_enable_default() out of bfq's exit(), and call it from elevator_change_done(). Meantime add disk->rqos_state_mutex for covering wbt state change, which matches the purpose more than ->elevator_lock. Signed-off-by: Ming Lei --- block/bfq-iosched.c | 2 +- block/blk-sysfs.c | 6 ++---- block/blk-wbt.c | 10 ++++++++-- block/elevator.c | 5 +++++ block/elevator.h | 1 + block/genhd.c | 1 + include/linux/blkdev.h | 2 ++ 7 files changed, 20 insertions(+), 7 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index cc6f59836dcd..0cb1e9873aab 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -7211,7 +7211,7 @@ static void bfq_exit_queue(struct elevator_queue *e) blk_stat_disable_accounting(bfqd->queue); blk_queue_flag_clear(QUEUE_FLAG_DISABLE_WBT_DEF, bfqd->queue); - wbt_enable_default(bfqd->queue->disk); + set_bit(ELEVATOR_FLAG_ENABLE_WBT_ON_EXIT, &e->flags); kfree(bfqd); } diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 9aa05666f32a..fafe9e9e97cc 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -593,7 +593,7 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, return -EINVAL; memflags = blk_mq_freeze_queue(q); - mutex_lock(&q->elevator_lock); + mutex_lock(&disk->rqos_state_mutex); rqos = wbt_rq_qos(q); if (!rqos) { @@ -622,7 +622,7 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, blk_mq_unquiesce_queue(q); out: - mutex_unlock(&q->elevator_lock); + mutex_unlock(&disk->rqos_state_mutex); blk_mq_unfreeze_queue(q, memflags); return ret; @@ -870,9 +870,7 @@ int blk_register_queue(struct gendisk *disk) goto out_unregister_ia_ranges; elevator_set_default(q); - mutex_lock(&q->elevator_lock); wbt_enable_default(disk); - mutex_unlock(&q->elevator_lock); blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q); diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 29cd2e33666f..c8588bae1c1b 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -704,6 +704,8 @@ void wbt_enable_default(struct gendisk *disk) struct rq_qos *rqos; bool enable = IS_ENABLED(CONFIG_BLK_WBT_MQ); + mutex_lock(&disk->rqos_state_mutex); + if (blk_queue_disable_wbt(q)) enable = false; @@ -712,15 +714,17 @@ void wbt_enable_default(struct gendisk *disk) if (rqos) { if (enable && RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT) RQWB(rqos)->enable_state = WBT_STATE_ON_DEFAULT; - return; + goto unlock; } /* Queue not registered? Maybe shutting down... */ if (!blk_queue_registered(q)) - return; + goto unlock; if (queue_is_mq(q) && enable) wbt_init(disk); +unlock: + mutex_unlock(&disk->rqos_state_mutex); } EXPORT_SYMBOL_GPL(wbt_enable_default); @@ -773,11 +777,13 @@ void wbt_disable_default(struct gendisk *disk) struct rq_wb *rwb; if (!rqos) return; + mutex_lock(&disk->rqos_state_mutex); rwb = RQWB(rqos); if (rwb->enable_state == WBT_STATE_ON_DEFAULT) { blk_stat_deactivate(rwb->cb); rwb->enable_state = WBT_STATE_OFF_DEFAULT; } + mutex_unlock(&disk->rqos_state_mutex); } EXPORT_SYMBOL_GPL(wbt_disable_default); diff --git a/block/elevator.c b/block/elevator.c index aec8081a6be3..a637426da56d 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -663,8 +663,13 @@ static int elevator_change_done(struct request_queue *q, int ret = 0; if (ctx->old) { + bool enable_wbt = test_bit(ELEVATOR_FLAG_ENABLE_WBT_ON_EXIT, + &ctx->old->flags); + elv_unregister_queue(q, ctx->old); kobject_put(&ctx->old->kobj); + if (enable_wbt) + wbt_enable_default(q->disk); } if (ctx->new) { ret = elv_register_queue(q, ctx->new, ctx->uevent); diff --git a/block/elevator.h b/block/elevator.h index 76a90a1b7ed6..a07ce773a38f 100644 --- a/block/elevator.h +++ b/block/elevator.h @@ -122,6 +122,7 @@ struct elevator_queue #define ELEVATOR_FLAG_REGISTERED 0 #define ELEVATOR_FLAG_DYING 1 +#define ELEVATOR_FLAG_ENABLE_WBT_ON_EXIT 2 /* * block elevator interface diff --git a/block/genhd.c b/block/genhd.c index a50063c4c40f..e13be309552a 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1452,6 +1452,7 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id, #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED INIT_LIST_HEAD(&disk->slave_bdevs); #endif + mutex_init(&disk->rqos_state_mutex); return disk; out_erase_part0: diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 228b2e5ad493..281d56b910c2 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -218,6 +218,8 @@ struct gendisk { * devices that do not have multiple independent access ranges. */ struct blk_independent_access_ranges *ia_ranges; + + struct mutex rqos_state_mutex; /* rqos state change mutex */ }; /** -- 2.47.0