From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 388A3C43387 for ; Mon, 7 Jan 2019 16:06:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0510B2087F for ; Mon, 7 Jan 2019 16:06:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="mB+PZFoH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728260AbfAGQGs (ORCPT ); Mon, 7 Jan 2019 11:06:48 -0500 Received: from mail-io1-f67.google.com ([209.85.166.67]:35532 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728308AbfAGQGs (ORCPT ); Mon, 7 Jan 2019 11:06:48 -0500 Received: by mail-io1-f67.google.com with SMTP id f4so721579ion.2 for ; Mon, 07 Jan 2019 08:06:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=XtDT2JP307s8ZH2j7Q3doY0W4PCMWIm4eGNNhmfF5OE=; b=mB+PZFoHkA8I2m4TvLmXKQqF2eDHxbpPeZ8wESxPLb21IzH92hdtg8I888oHofmQlU c/SNQq/VGLeH7ZIhgMsG+AU+0CoZjT/yO3CKPtbzgLoAJfh7rK7yLfGd8G2+UcgMAW2P cUT86veo6clgeLTszQ0gxvdPtqIFt3X9TyLYL0WOIT2XJnHIyy0rVeHg/p/dh86za86y 6JVXbWbRIwZ66yrOVCsy8yyClaYRwpZSnfFOlX7jS1vIhfb3+6MQK3hlFkPvkSBiJ8cT PnnHBkqrReGLZ4ioryupC+1aCLs4hl39RuIUnlHc2ItzqAf9mesXEcW0lEzW0qMCenwj jDkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=XtDT2JP307s8ZH2j7Q3doY0W4PCMWIm4eGNNhmfF5OE=; b=JdWXEi8okeFDGq8dZ1Z3P3lrzG02QslZa4xBsLMZUH63fUzFFBKTUFlvqUwT+D3a5C iyLN/Q699AGEiO1gb3eS8w3dwF8enXtIler/D8/dkFknEjChXDkR5PwW1P6jXIQSD+xY U2VQriW4wsuuLBey7+eFgNKxcWfEQ8XhFU13RfVSPxwTFU+jVDuS2mXeYk9KIIuGlo62 lJuQVQYyZXX8MjyQQPD6s5fGrEc/ZWsL76A1knBiSd1qdXkkdvDL1hQUzxFe424p+x+p cGcmFLEcSSwQWg6kM4k92hk6qQpwPQIck3mpvn6yqtAMGDRS2mJh4vZIvKom6upINQQs ZtRg== X-Gm-Message-State: AJcUukfhqL8ODAbFRyYX23+fjiS3CnEnsdf8DGuF+AH5W9m6l2oF/6Sr K3y5DqxragZoVjnOkP/+Txk3FhvuHY01dw== X-Google-Smtp-Source: ALg8bN78mnqqk+rpMD3zyZQ2AXkNBH41IbVlnyGKOmYBrUnskCbH4aGwEKEbuTVeRTja7yDTUtwNXw== X-Received: by 2002:a5e:a619:: with SMTP id q25mr44245301ioi.82.1546877206901; Mon, 07 Jan 2019 08:06:46 -0800 (PST) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id 195sm4448724itm.2.2019.01.07.08.06.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Jan 2019 08:06:45 -0800 (PST) Subject: Re: [PATCH] block: don't show io_timeout if driver has no timeout handler To: Bart Van Assche , hch@infradead.org, linux-block@vger.kernel.org References: <20190107125215.GA5039@192.168.3.9> <1546877098.83374.9.camel@acm.org> From: Jens Axboe Message-ID: <6d2ef1a5-94a2-a4a5-d60a-845c13a6bda1@kernel.dk> Date: Mon, 7 Jan 2019 09:06:44 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1546877098.83374.9.camel@acm.org> Content-Type: text/plain; charset=UTF-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 1/7/19 9:04 AM, Bart Van Assche wrote: > On Mon, 2019-01-07 at 08:43 -0700, Jens Axboe wrote: >> On 1/7/19 5:52 AM, Weiping Zhang wrote: >>> If the low level driver has no timerout handler, the >>> /sys/block//queue/io_timeout will not be displayed. >> >> The alternative would be to make it return an error when read/written >> instead of having this separate group code. > > Hi Jens, > > Christoph and I had asked Weiping to use a sysfs attribute group. See also > https://www.mail-archive.com/linux-block@vger.kernel.org/msg25841.html I think both solutions have parts that suck. If the file is only there for some devices, that's a bit of an API wart. But at the same time, if the file is there and not readable/writeable on those same devices, that's also kind of ugly (as the wbt exercise has shown). -- Jens Axboe