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 4C0CB6AD3 for ; Wed, 30 Apr 2025 04:37:12 +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=1745987837; cv=none; b=qe4q/NVf+DcjFmpSWavXMM2QQjSgGm6zOgraDu5ZUmHAEakEnDrkViRxILj7Td/lXQJx4gkcpK5j/0RZNA34gbMsyUmj3H8Szwaz/gO6eD6hzGt4javyMVnVk7eXRt6O1B+4EJfSkVKIA0RtZWD1NL/aK33cOYkw9TBsOYkKsn0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745987837; c=relaxed/simple; bh=bZmET45OGOCMwc+Q4v+WeWO877s4t8N6G9wMi+uN5/Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k3tu1ohhChERb9A3IsYnwJhEuPq/B2bdMCleKkrVAczMDeYOgwjdP+T+Lj+KUCFfPWiUmsINwI3CbX41Wft9DROeHwtuYAiqp2Jc4h4s4qodbMyUeHRHoB3nr4nnEC1QhxvTd0bbLCNnH4JQFk7tvOYRoqZQh7HfUWjpyOkkc5M= 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=T/qMs7tu; 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="T/qMs7tu" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1745987832; 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=IjixIQR8SwWl5Yd+txBqJPl2CTbBY7tIhe/IxpvdnyY=; b=T/qMs7tubRPK/hR8PiD+36VMQN5NOqNykuB38AelXRA3PwHBJW0BTd1Um9zKgQY0evsy6T 7V3O4Lg/yrYJv5cCKmM7rfZHYMzFr0jA+4Aa+o/5xzPwURhK9kL2UvtEoH9RsbUQQr/wm5 dxlkWmjjowQ2Nxip8cjosT/M8GxellA= Received: from mx-prod-mc-05.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-685-U9QjP4LVOh-KaAi6Qgmblg-1; Wed, 30 Apr 2025 00:37:07 -0400 X-MC-Unique: U9QjP4LVOh-KaAi6Qgmblg-1 X-Mimecast-MFC-AGG-ID: U9QjP4LVOh-KaAi6Qgmblg_1745987826 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A58531956086; Wed, 30 Apr 2025 04:37:06 +0000 (UTC) Received: from localhost (unknown [10.72.116.48]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 87481180045C; Wed, 30 Apr 2025 04:37:05 +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 V4 24/24] block: move wbt_enable_default() out of queue freezing from sched ->exit() Date: Wed, 30 Apr 2025 12:35:26 +0800 Message-ID: <20250430043529.1950194-25-ming.lei@redhat.com> In-Reply-To: <20250430043529.1950194-1-ming.lei@redhat.com> References: <20250430043529.1950194-1-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 10.30.177.93 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. Reviewed-by: Nilay Shroff Signed-off-by: Ming Lei --- block/bfq-iosched.c | 2 +- block/blk-sysfs.c | 10 ++++------ block/blk-wbt.c | 6 ++++++ 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 741e607dfab6..01e0ead13278 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -560,7 +560,7 @@ static ssize_t queue_wb_lat_show(struct gendisk *disk, char *page) ssize_t ret; struct request_queue *q = disk->queue; - mutex_lock(&q->elevator_lock); + mutex_lock(&disk->rqos_state_mutex); if (!wbt_rq_qos(q)) { ret = -EINVAL; goto out; @@ -573,7 +573,7 @@ static ssize_t queue_wb_lat_show(struct gendisk *disk, char *page) ret = sysfs_emit(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000)); out: - mutex_unlock(&q->elevator_lock); + mutex_unlock(&disk->rqos_state_mutex); return ret; } @@ -593,7 +593,6 @@ 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); rqos = wbt_rq_qos(q); if (!rqos) { @@ -618,11 +617,12 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, */ blk_mq_quiesce_queue(q); + mutex_lock(&disk->rqos_state_mutex); wbt_set_min_lat(q, val); + mutex_unlock(&disk->rqos_state_mutex); blk_mq_unquiesce_queue(q); out: - mutex_unlock(&q->elevator_lock); blk_mq_unfreeze_queue(q, memflags); return ret; @@ -871,9 +871,7 @@ int blk_register_queue(struct gendisk *disk) if (queue_is_mq(q)) 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..74ae7131ada9 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; @@ -712,8 +714,10 @@ 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; + mutex_unlock(&disk->rqos_state_mutex); return; } + mutex_unlock(&disk->rqos_state_mutex); /* Queue not registered? Maybe shutting down... */ if (!blk_queue_registered(q)) @@ -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 492a593160ae..936d73cda6ed 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -637,8 +637,13 @@ 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->no_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 59d9febd8c14..21b4ea191d24 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1460,6 +1460,7 @@ 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 b15c53fabe9f..c19ae1877061 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