From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751270AbdDBKJc (ORCPT ); Sun, 2 Apr 2017 06:09:32 -0400 Received: from www381.your-server.de ([78.46.137.84]:50078 "EHLO www381.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750947AbdDBKJa (ORCPT ); Sun, 2 Apr 2017 06:09:30 -0400 Subject: Re: [PATCH] iio: core: Fix IIO_VAL_FRACTIONAL_LOG2 for negative values To: Jonathan Cameron , Nikolaus Schulz , Hartmut Knaack , Peter Meerwald-Stadler , "open list:IIO SUBSYSTEM AND DRIVERS" , open list References: <1490359311-21042-1-git-send-email-nikolaus.schulz@avionic-design.de> <0cec95d3-0520-998e-fba2-de237659f3a1@kernel.org> Cc: stable@vger.kernel.org From: Lars-Peter Clausen Message-ID: Date: Sun, 2 Apr 2017 12:09:26 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.6.0 MIME-Version: 1.0 In-Reply-To: <0cec95d3-0520-998e-fba2-de237659f3a1@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Authenticated-Sender: lars@metafoo.de Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/02/2017 11:26 AM, Jonathan Cameron wrote: > On 25/03/17 18:03, Jonathan Cameron wrote: >> On 24/03/17 12:41, Nikolaus Schulz wrote: >>> Fix formatting of negative values of type IIO_VAL_FRACTIONAL_LOG2 by >>> switching from do_div(), which can't handle negative numbers, to >>> div_s64_rem(). Also use shift_right for shifting, which is safe with >>> negative values. >>> >>> Signed-off-by: Nikolaus Schulz >>> Cc: stable@vger.kernel.org >> Looks sane to me, but I'd like to give others time to comment on this >> just in case there is some odd condition neither of us has thought of! >> >> Give me a poke if we get nothing else for a few weeks. > Lars, I think this might have been your magic in the first place. > > Could you sanity check this one please. It's in the category of very > risky of both Nikolaus and I have missed something! It's the same as this: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/iio/industrialio-core.c?id=171c0091837c81ed5c949fec6966bb5afff2d1cf Should be OK. Reviewed-by: Lars-Peter Clausen > > Thanks, > > Jonathan >> >> Jonathan >>> --- >>> drivers/iio/industrialio-core.c | 7 +++---- >>> 1 file changed, 3 insertions(+), 4 deletions(-) >>> >>> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c >>> index d18ded4..3ff91e0 100644 >>> --- a/drivers/iio/industrialio-core.c >>> +++ b/drivers/iio/industrialio-core.c >>> @@ -610,10 +610,9 @@ static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type, >>> tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1); >>> return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); >>> case IIO_VAL_FRACTIONAL_LOG2: >>> - tmp = (s64)vals[0] * 1000000000LL >> vals[1]; >>> - tmp1 = do_div(tmp, 1000000000LL); >>> - tmp0 = tmp; >>> - return snprintf(buf, len, "%d.%09u", tmp0, tmp1); >>> + tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]); >>> + tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1); >>> + return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); >>> case IIO_VAL_INT_MULTIPLE: >>> { >>> int i; >>> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-iio" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >