From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752603AbeC1Co3 (ORCPT ); Tue, 27 Mar 2018 22:44:29 -0400 Received: from mail-pl0-f68.google.com ([209.85.160.68]:43086 "EHLO mail-pl0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750753AbeC1Co1 (ORCPT ); Tue, 27 Mar 2018 22:44:27 -0400 X-Google-Smtp-Source: AIpwx48/EYatAcIm4gbdZUKKsxK7eojXC8AH/t0E4xIr5BZUQtinutrI6T2RAWQHp7pNRGHo8xisqQ== Date: Wed, 28 Mar 2018 11:44:22 +0900 From: Sergey Senozhatsky To: wen.yang99@zte.com.cn Cc: Bart.VanAssche@wdc.com, sergey.senozhatsky.work@gmail.com, pmladek@suse.com, jejb@linux.vnet.ibm.com, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, jiang.biao2@zte.com.cn, zhong.weidong@zte.com.cn, tan.hu@zte.com.cn Subject: Re: =?utf-8?B?562U5aSNOiBSZTogW1BBVENI?= =?utf-8?Q?=5D?= scsi: Replace sdev_printk with printk_deferred to avoid Message-ID: <20180328024422.GA1352@jagdpanzerIV> References: <199ab05df000f2e8b5497a7aaecd0951321aadae.camel@wdc.com> <201803281029555635678@zte.com.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201803281029555635678@zte.com.cn> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (03/28/18 10:29), wen.yang99@zte.com.cn wrote: > Hello Bart, > > We have a detailed discussion of the problem. > Sergey Senozhatsky, Petr and many people have made a lot of efforts about > it. > Please see this link: > https://bugzilla.kernel.org/show_bug.cgi?id=199003 > > 1, Petr suggests that it should be modified in this way: > IMHO, printing the same message so many times is useless. Therefore > some throttling would make sense. If we want to keep sdev_printk(), The thing with retelimiting is that - yes, we do less printks but we still do them under queue spin_lock. So I was thinking about something like below [a quick-n-dirty workaround] --- drivers/scsi/scsi_lib.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 0dfec0dedd5e..6c930fbdd24c 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1825,9 +1825,13 @@ static void scsi_request_fn(struct request_queue *q) break; if (unlikely(!scsi_device_online(sdev))) { + scsi_kill_request(req, q); + spin_unlock_irq(q->queue_lock); + sdev_printk(KERN_ERR, sdev, "rejecting I/O to offline device\n"); - scsi_kill_request(req, q); + + spin_lock_irq(q->queue_lock); continue; }