From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-x229.google.com (mail-pa0-x229.google.com [IPv6:2607:f8b0:400e:c03::229]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id A02401A0174 for ; Wed, 27 Jan 2016 14:19:11 +1100 (AEDT) Received: by mail-pa0-x229.google.com with SMTP id ho8so108167191pac.2 for ; Tue, 26 Jan 2016 19:19:11 -0800 (PST) Subject: Re: [kernel] powerpc: Make vmalloc_to_phys() public To: Paul Mackerras , Michael Ellerman References: <1453361708-19422-1-git-send-email-aik@ozlabs.ru> <20160125054603.5D55B140326@ozlabs.org> <20160125100609.GA24295@fergus.ozlabs.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org From: Alexey Kardashevskiy Message-ID: <56A83728.4090601@ozlabs.ru> Date: Wed, 27 Jan 2016 14:19:04 +1100 MIME-Version: 1.0 In-Reply-To: <20160125100609.GA24295@fergus.ozlabs.ibm.com> Content-Type: text/plain; charset=koi8-r; format=flowed List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 01/25/2016 09:06 PM, Paul Mackerras wrote: > On Mon, Jan 25, 2016 at 04:46:03PM +1100, Michael Ellerman wrote: >> On Thu, 2016-21-01 at 07:35:08 UTC, Alexey Kardashevskiy wrote: >>> This makes vmalloc_to_phys() public as there will be another user >>> (in-kernel VFIO acceleration) for it soon. >>> >>> As a part of future little optimization, this changes the helper to call >>> vmalloc_to_pfn() instead of vmalloc_to_page() as the size of the >>> struct page may not be power-of-two aligned which will make gcc use >>> multiply instructions instead of shifts. >> >> You should also mention why you need to export it, presumably because whatever >> new user you have in mind can be built as a module. > > If I remember correctly, it's the *existing* user in hv-24x7.c that > needs the export. No, CONFIG_HV_PERF_CTRS (which controls hv-24x7.c) is "bool" so today hv-24x7.c cannot compile as a module. This exports the vmalloc_to_phys() symbol as a new user is going to be KVM which can compile as a module. -- Alexey