From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 50AC92248A5; Tue, 26 Aug 2025 11:20:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756207257; cv=none; b=XKDIjj0mhWTwqEVUlbYLKPQuxH6/U+h12PdzPnaNdBm5v0hfT9pLgkd4DhDbF59DD/ohqMTu1zfHTslrg2ZvNmDBEZIruyaLmTOD/nFlsj8uP6jLetzIXsmmfj3GQUnkW1Ngrja4cpelXlpDu84u4bSh1fxnvkeEOJWipxMrAjk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756207257; c=relaxed/simple; bh=g7hDztYRr4I/8SrnsyjsP3aAUBIA5GRra0VdNyg38jQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YpH4lFK8enzonSmgv4vDkj1nq7l7aj/zTLnvIkXsrEoBHpTLxRQJe9IW2g1y2PxBaLfXV60+EqF7M7eWD4So7DGSR5ySRYnruJ0Io8jpG52gfinznESrjBof3iQOMcLQtF4izi8CCOOvC5f2RAuUjqRta4DJn5aLzS1NJS/Q8Xs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dXRm1f8B; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dXRm1f8B" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D56BAC4CEF1; Tue, 26 Aug 2025 11:20:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756207257; bh=g7hDztYRr4I/8SrnsyjsP3aAUBIA5GRra0VdNyg38jQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dXRm1f8BQVuTuFKct6zdebKxf3mgAB0WOHF+P8rfoQPOuHOI07HgcSy/0z7aF6fds ezZKwLTqLBaSt5j5Ppee8Df//mX8Oc54wqbiYaUbw06QAB2548WDXGlct/jPfiUuFo hlOeRNg4cK7m6UB75qGAH0p+Azzf5eRguDGoveZU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Julian Sun , Nilay Shroff , Yu Kuai , Ming Lei , Jens Axboe Subject: [PATCH 6.16 110/457] block: restore default wbt enablement Date: Tue, 26 Aug 2025 13:06:34 +0200 Message-ID: <20250826110940.089643504@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110937.289866482@linuxfoundation.org> References: <20250826110937.289866482@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Julian Sun commit 8f5845e0743bf3512b71b3cb8afe06c192d6acc4 upstream. The commit 245618f8e45f ("block: protect wbt_lat_usec using q->elevator_lock") protected wbt_enable_default() with q->elevator_lock; however, it also placed wbt_enable_default() before blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);, resulting in wbt failing to be enabled. Moreover, the protection of wbt_enable_default() by q->elevator_lock was removed in commit 78c271344b6f ("block: move wbt_enable_default() out of queue freezing from sched ->exit()"), so we can directly fix this issue by placing wbt_enable_default() after blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);. Additionally, this issue also causes the inability to read the wbt_lat_usec file, and the scenario is as follows: root@q:/sys/block/sda/queue# cat wbt_lat_usec cat: wbt_lat_usec: Invalid argument root@q:/data00/sjc/linux# ls /sys/kernel/debug/block/sda/rqos cannot access '/sys/kernel/debug/block/sda/rqos': No such file or directory root@q:/data00/sjc/linux# find /sys -name wbt /sys/kernel/debug/tracing/events/wbt After testing with this patch, wbt can be enabled normally. Signed-off-by: Julian Sun Cc: stable@vger.kernel.org Fixes: 245618f8e45f ("block: protect wbt_lat_usec using q->elevator_lock") Reviewed-by: Nilay Shroff Reviewed-by: Yu Kuai Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20250812154257.57540-1-sunjunchao@bytedance.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/blk-sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -876,9 +876,9 @@ int blk_register_queue(struct gendisk *d if (queue_is_mq(q)) elevator_set_default(q); - wbt_enable_default(disk); blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q); + wbt_enable_default(disk); /* Now everything is ready and send out KOBJ_ADD uevent */ kobject_uevent(&disk->queue_kobj, KOBJ_ADD);