From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f72.google.com (mail-oi0-f72.google.com [209.85.218.72]) by kanga.kvack.org (Postfix) with ESMTP id 6F6F16B0038 for ; Fri, 3 Nov 2017 09:31:22 -0400 (EDT) Received: by mail-oi0-f72.google.com with SMTP id m198so2731468oig.20 for ; Fri, 03 Nov 2017 06:31:22 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id i7sor2186735oia.266.2017.11.03.06.31.20 for (Google Transport Security); Fri, 03 Nov 2017 06:31:20 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20171103112121.23597-1-jack@suse.cz> References: <20171103112121.23597-1-jack@suse.cz> From: Dan Williams Date: Fri, 3 Nov 2017 06:31:19 -0700 Message-ID: Subject: Re: [PATCH] mm: Handle 0 flags in _calc_vm_trans() macro Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: Ross Zwisler , Linux MM , Christoph Hellwig On Fri, Nov 3, 2017 at 4:21 AM, Jan Kara wrote: > _calc_vm_trans() does not handle the situation when some of the passed > flags are 0 (which can happen if these VM flags do not make sense for > the architecture). Improve the _calc_vm_trans() macro to return 0 in > such situation. Since all passed flags are constant, this does not add > any runtime overhead. > > Signed-off-by: Jan Kara > --- > include/linux/mman.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > Dan, can you please prepend this patch before my series so that we don't > break bisectability? This fixes the reported problem for me when arch > does not define MAP_SYNC. Thanks! > > diff --git a/include/linux/mman.h b/include/linux/mman.h > index 8f7cc87828e6..3427bf3daef5 100644 > --- a/include/linux/mman.h > +++ b/include/linux/mman.h > @@ -105,8 +105,9 @@ static inline bool arch_validate_prot(unsigned long prot) > * ("bit1" and "bit2" must be single bits) > */ > #define _calc_vm_trans(x, bit1, bit2) \ > + ((!(bit1) || !(bit2)) ? 0 : \ > ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \ > - : ((x) & (bit1)) / ((bit1) / (bit2))) > + : ((x) & (bit1)) / ((bit1) / (bit2)))) > Looks good to me, thanks Jan. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org