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=-2.2 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 91DF1C433F4 for ; Tue, 28 Aug 2018 22:04:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 373F720880 for ; Tue, 28 Aug 2018 22:04:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="o0oUUrY5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 373F720880 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727356AbeH2B6I (ORCPT ); Tue, 28 Aug 2018 21:58:08 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:55552 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727067AbeH2B6H (ORCPT ); Tue, 28 Aug 2018 21:58:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=KLDEt+uQCAiMUZcj+l7cWxyM2azHLk+NlXUdok09dRg=; b=o0oUUrY5xBqhwfs2emUh4eTb2 JKYxAdgckP3sZ6m06c7N2Ye3X8Dfke+yH/XyAVmZBkUPc/7YxZxREGSijJFoQrk6fgqr14PnIrDwM sAYxMkJeJ3mBKEcBD66Hgtxog+o6sBkPeNQuud/gdfv3hlpOjRFEHPl8ZPtuA1z7SgvlIAiURsOsb aV8MiWph3saiiUFD3NYpMFLW45wpOylgqh9kC857WXEaGm1CAUEz5LfgeF0DQmSVMHX+tERgBcTQ8 NYBmF+mhsrwdsSFC7wtYn3o0Xgpy8YTb6Jfqnqo27SS0QBx9VEPpk3BMqmfQ+LkA82RdmxXUjBtoZ X1eHU5+6g==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1fum67-000610-EN; Tue, 28 Aug 2018 22:04:27 +0000 Date: Tue, 28 Aug 2018 15:04:27 -0700 From: Matthew Wilcox To: Nicolas Pitre Cc: Andrew Morton , Souptick Joarder , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 01/10] cramfs: Convert to use vmf_insert_mixed Message-ID: <20180828220427.GA11400@bombadil.infradead.org> References: <20180828145728.11873-1-willy@infradead.org> <20180828145728.11873-2-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 28, 2018 at 01:49:25PM -0400, Nicolas Pitre wrote: > On Tue, 28 Aug 2018, Matthew Wilcox wrote: > > - ret = vm_insert_mixed(vma, vma->vm_start + off, pfn); > > + vmf = vmf_insert_mixed(vma, vma->vm_start + off, pfn); > > + if (vmf & VM_FAULT_ERROR) { > > + pages = i; > > + break; > > + } > > I'd suggest this to properly deal with errers instead: > > - ret = vm_insert_mixed(vma, vma->vm_start + off, pfn); > + vmf = vmf_insert_mixed(vma, vma->vm_start + off, pfn); > + if (vmf & VM_FAULT_ERROR) > + ret = vm_fault_to_errno(vmf, 0); By my reading of this function, the intent is actually to return 0 here and allow demand paging to work. Of course, I've spent all of twenty minutes staring at this function, so I defer to the maintainer. I think you'd need to be running a make-memory-allocations-fail fuzzer to hit this, so it's likely never been tested.