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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 3BD19C433E7 for ; Fri, 9 Oct 2020 12:31:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A9284222B8 for ; Fri, 9 Oct 2020 12:31:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="cdaBlGmB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A9284222B8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C8F276B0062; Fri, 9 Oct 2020 08:31:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C3EA66B0068; Fri, 9 Oct 2020 08:31:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AB8298E0001; Fri, 9 Oct 2020 08:31:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0061.hostedemail.com [216.40.44.61]) by kanga.kvack.org (Postfix) with ESMTP id 8058A6B0062 for ; Fri, 9 Oct 2020 08:31:13 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 0D4DB181AE86B for ; Fri, 9 Oct 2020 12:31:13 +0000 (UTC) X-FDA: 77352322026.21.deer50_2201b2a271e0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id C4CF2180442C2 for ; Fri, 9 Oct 2020 12:31:12 +0000 (UTC) X-HE-Tag: deer50_2201b2a271e0 X-Filterd-Recvd-Size: 4433 Received: from mail-qt1-f196.google.com (mail-qt1-f196.google.com [209.85.160.196]) by imf17.hostedemail.com (Postfix) with ESMTP for ; Fri, 9 Oct 2020 12:31:12 +0000 (UTC) Received: by mail-qt1-f196.google.com with SMTP id h12so6196789qtu.1 for ; Fri, 09 Oct 2020 05:31:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=K8oqjNwy1IItwzS5nAtnJfKoqbYdlnvHoUJ/yQIxMlE=; b=cdaBlGmBZL4cakXZlvJuZERmIRIX6jD7dwzimgC10KWdoWEXxqnVyCAO2D0RVxCrE3 SiHI343vdap2cRRglH6ua6mGWuo7/fxfox6RkGqmDhIsAnKFSeohUX9VYGJSKAwhIU6B 2TcxKC37KpT1QUH/a9OmlQtDEo327+kakIXLdXGqBOKFhRN4BS67JiDu+bvG4a5CPI+r pqcyhIAj+gFL2/lmzDWusy4E62ErCo67w+IagQCo+gX4l+6CaOr61WFu2i1yy0l+Wgf3 xGuhQ4gDKh6os3wK0BjatM5g2y6nWPQvLIHBtHwaCM52uhc/sKGK0XWe8qKcZr9st8fm fLCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=K8oqjNwy1IItwzS5nAtnJfKoqbYdlnvHoUJ/yQIxMlE=; b=Y36vQdopTxuj+fnHQqhlFYpWWL4k6PzLXtoUCI2gQSktFUvI7/g7F0RWRLt8iywlDQ ZEoEaUbzxYL2IZgsjt2XMBP67HKALfIYJrqK5GkDMLlbeOepl5rK6GvY4MnVELBoev/7 XUnwPrbNyX/q741b8N0Vfl4DyZ6bRmy3Goru9tN2bXXIUt9b8Q2/4FD816nNGv6lAPdJ AXHDsWeXBFTInSz92aN++5qZQvMC/3uvsp5txLm8FQlHj5X1/ku2/BnTF4KA1vZUTWOA cpN7y4q4Gw7zyuEADYQY8EHZRDkBvRBc3wL6jYQTI2oSwjTcXU6ZhVIHm1WMv+aDSV3M FdHg== X-Gm-Message-State: AOAM5307MuDZ3PGp1GCYdBBWzowKR3vtirHrx0e+3CnVAWUDW45ZveXS Gzci3xxb35bwD4lgnJGJK3YIjg== X-Google-Smtp-Source: ABdhPJxG8zCIXDditfEGKgb8JSFeGI61awPyS7AMuV2YFh9LkEtvSTVL1XgAfKTEjxIzUEviyqvgUw== X-Received: by 2002:ac8:d8d:: with SMTP id s13mr12568868qti.42.1602246671500; Fri, 09 Oct 2020 05:31:11 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id g1sm6069368qtp.74.2020.10.09.05.31.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2020 05:31:10 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kQrYD-001xsF-Sz; Fri, 09 Oct 2020 09:31:09 -0300 Date: Fri, 9 Oct 2020 09:31:09 -0300 From: Jason Gunthorpe To: Daniel Vetter Cc: DRI Development , LKML , kvm@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, linux-s390@vger.kernel.org, Daniel Vetter , Kees Cook , Dan Williams , Andrew Morton , John Hubbard , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Jan Kara , Arnd Bergmann , Greg Kroah-Hartman , David Hildenbrand , "Rafael J. Wysocki" Subject: Re: [PATCH v2 14/17] resource: Move devmem revoke code to resource framework Message-ID: <20201009123109.GO5177@ziepe.ca> References: <20201009075934.3509076-1-daniel.vetter@ffwll.ch> <20201009075934.3509076-15-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201009075934.3509076-15-daniel.vetter@ffwll.ch> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Oct 09, 2020 at 09:59:31AM +0200, Daniel Vetter wrote: > +struct address_space *iomem_get_mapping(void) > +{ > + return iomem_inode->i_mapping; This should pair an acquire with the release below > + /* > + * Publish /dev/mem initialized. > + * Pairs with smp_load_acquire() in revoke_iomem(). > + */ > + smp_store_release(&iomem_inode, inode); However, this seems abnormal, initcalls rarely do this kind of stuff with global data.. The kernel crashes if this fs_initcall is raced with iomem_get_mapping() due to the unconditional dereference, so I think it can be safely switched to a simple assignment. Jason