From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH][RESEND] scsi_sysfs: add 'is_bin_visible' callback Date: Wed, 2 Mar 2016 17:34:48 +0800 Message-ID: <56D6B3B8.8070109@suse.com> References: <1456807945-88857-1-git-send-email-hare@suse.de> <20160301130448.GB7616@lst.de> <56D6973A.4070901@suse.de> <20160302091916.GE1308@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.nue.novell.com ([195.135.221.5]:46216 "EHLO smtp.nue.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754611AbcCBJfH (ORCPT ); Wed, 2 Mar 2016 04:35:07 -0500 In-Reply-To: <20160302091916.GE1308@lst.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig , Hannes Reinecke Cc: "Martin K. Petersen" , Ewan Milne , Bart van Assche , James Bottomley , linux-scsi@vger.kernel.org On 03/02/2016 05:19 PM, Christoph Hellwig wrote: > On Wed, Mar 02, 2016 at 03:33:14PM +0800, Hannes Reinecke wrote: >>>> + rcu_read_lock(); >>>> + if (attr == &dev_attr_vpd_pg80 && >>>> + !rcu_dereference(sdev->vpd_pg80)) { >>>> + rcu_read_unlock(); >>>> + return 0; >>>> + } >>>> + if (attr == &dev_attr_vpd_pg83 && >>>> + !rcu_dereference(sdev->vpd_pg83)) { >>>> + rcu_read_unlock(); >>>> + return 0; >>>> + } >>>> + rcu_read_unlock(); >>> >>> We are only checking the pointers for being non-zero. No need for the >>> rcu_read_lock() or rcu_dereference() here. >>> >> Better to be same than sorry; some overly clever code analysis tool >> might trip over it otherwise. > > It shouldn't. There is no dereference going on here. > Ok. >> >>> Otherwise this looks fine to me. >> >> Reviewed-by: ? > > Only without the cargo culted rcu magic. > Okay, will be resending it. Cheers, Hannes