From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753528AbbKXMtE (ORCPT ); Tue, 24 Nov 2015 07:49:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:53256 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753335AbbKXMtB (ORCPT ); Tue, 24 Nov 2015 07:49:01 -0500 Message-ID: <1448369339.2877.30.camel@suse.de> Subject: Re: [PATCH] scsi: use sector_div instead of do_div From: Johannes Thumshirn To: Arnd Bergmann , linux-scsi@vger.kernel.org Cc: jbottomley@odin.com, martin.petersen@oracle.com, nico@fluxnic.net, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Date: Tue, 24 Nov 2015 13:48:59 +0100 In-Reply-To: <24882658.08y4bWL6tn@wuerfel> References: <24882658.08y4bWL6tn@wuerfel> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2015-11-20 at 17:38 +0100, Arnd Bergmann wrote: > do_div is the wrong way to divide a sector_t, as it is less > efficient when sector_t is 32-bit wide. With the upcoming > do_div optimizations, the kernel starts warning about this: > > drivers/scsi/scsi_debug.c: In function 'dif_store': > include/asm-generic/div64.h:207:28: warning: comparison of distinct > pointer types lacks a cast > > This changes the code to use sector_div instead, which always > produces optimal code. > > Signed-off-by: Arnd Bergmann > --- > Found on the ARM randconfig build today, after I merged Nico's > patches > for linux-next > > diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c > index dfcc45bb03b1..ec622ba9864a 100644 > --- a/drivers/scsi/scsi_debug.c > +++ b/drivers/scsi/scsi_debug.c > @@ -678,7 +678,7 @@ static void *fake_store(unsigned long long lba) >   >  static struct sd_dif_tuple *dif_store(sector_t sector) >  { > - sector = do_div(sector, sdebug_store_sectors); > + sector = sector_div(sector, sdebug_store_sectors); >   >   return dif_storep + sector; >  } > @@ -2780,7 +2780,7 @@ static unsigned long lba_to_map_index(sector_t > lba) >   lba += scsi_debug_unmap_granularity - >   scsi_debug_unmap_alignment; >   } > - do_div(lba, scsi_debug_unmap_granularity); > + sector_div(lba, scsi_debug_unmap_granularity); >   >   return lba; >  } > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" > in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html Reviewed-by: Johannes Thumshirn From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Thumshirn Subject: Re: [PATCH] scsi: use sector_div instead of do_div Date: Tue, 24 Nov 2015 13:48:59 +0100 Message-ID: <1448369339.2877.30.camel@suse.de> References: <24882658.08y4bWL6tn@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mx2.suse.de ([195.135.220.15]:53256 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753335AbbKXMtB (ORCPT ); Tue, 24 Nov 2015 07:49:01 -0500 In-Reply-To: <24882658.08y4bWL6tn@wuerfel> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Arnd Bergmann , linux-scsi@vger.kernel.org Cc: jbottomley@odin.com, martin.petersen@oracle.com, nico@fluxnic.net, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org On Fri, 2015-11-20 at 17:38 +0100, Arnd Bergmann wrote: > do_div is the wrong way to divide a sector_t, as it is less > efficient when sector_t is 32-bit wide. With the upcoming > do_div optimizations, the kernel starts warning about this: >=20 > drivers/scsi/scsi_debug.c: In function 'dif_store': > include/asm-generic/div64.h:207:28: warning: comparison of distinct > pointer types lacks a cast >=20 > This changes the code to use sector_div instead, which always > produces optimal code. >=20 > Signed-off-by: Arnd Bergmann > --- > Found on the ARM randconfig build today, after I merged Nico's > patches > for linux-next >=20 > diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c > index dfcc45bb03b1..ec622ba9864a 100644 > --- a/drivers/scsi/scsi_debug.c > +++ b/drivers/scsi/scsi_debug.c > @@ -678,7 +678,7 @@ static void *fake_store(unsigned long long lba) > =C2=A0 > =C2=A0static struct sd_dif_tuple *dif_store(sector_t sector) > =C2=A0{ > - sector =3D do_div(sector, sdebug_store_sectors); > + sector =3D sector_div(sector, sdebug_store_sectors); > =C2=A0 > =C2=A0 return dif_storep + sector; > =C2=A0} > @@ -2780,7 +2780,7 @@ static unsigned long lba_to_map_index(sector_t > lba) > =C2=A0 lba +=3D scsi_debug_unmap_granularity - > =C2=A0 scsi_debug_unmap_alignment; > =C2=A0 } > - do_div(lba, scsi_debug_unmap_granularity); > + sector_div(lba, scsi_debug_unmap_granularity); > =C2=A0 > =C2=A0 return lba; > =C2=A0} >=20 > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi"= =20 > in > the body of a message to majordomo@vger.kernel.org > More majordomo info at=C2=A0=C2=A0http://vger.kernel.org/majordomo-in= fo.html Reviewed-by: Johannes Thumshirn -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: jthumshirn@suse.de (Johannes Thumshirn) Date: Tue, 24 Nov 2015 13:48:59 +0100 Subject: [PATCH] scsi: use sector_div instead of do_div In-Reply-To: <24882658.08y4bWL6tn@wuerfel> References: <24882658.08y4bWL6tn@wuerfel> Message-ID: <1448369339.2877.30.camel@suse.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, 2015-11-20 at 17:38 +0100, Arnd Bergmann wrote: > do_div is the wrong way to divide a sector_t, as it is less > efficient when sector_t is 32-bit wide. With the upcoming > do_div optimizations, the kernel starts warning about this: > > drivers/scsi/scsi_debug.c: In function 'dif_store': > include/asm-generic/div64.h:207:28: warning: comparison of distinct > pointer types lacks a cast > > This changes the code to use sector_div instead, which always > produces optimal code. > > Signed-off-by: Arnd Bergmann > --- > Found on the ARM randconfig build today, after I merged Nico's > patches > for linux-next > > diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c > index dfcc45bb03b1..ec622ba9864a 100644 > --- a/drivers/scsi/scsi_debug.c > +++ b/drivers/scsi/scsi_debug.c > @@ -678,7 +678,7 @@ static void *fake_store(unsigned long long lba) > ? > ?static struct sd_dif_tuple *dif_store(sector_t sector) > ?{ > - sector = do_div(sector, sdebug_store_sectors); > + sector = sector_div(sector, sdebug_store_sectors); > ? > ? return dif_storep + sector; > ?} > @@ -2780,7 +2780,7 @@ static unsigned long lba_to_map_index(sector_t > lba) > ? lba += scsi_debug_unmap_granularity - > ? scsi_debug_unmap_alignment; > ? } > - do_div(lba, scsi_debug_unmap_granularity); > + sector_div(lba, scsi_debug_unmap_granularity); > ? > ? return lba; > ?} > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" > in > the body of a message to majordomo at vger.kernel.org > More majordomo info at??http://vger.kernel.org/majordomo-info.html Reviewed-by: Johannes Thumshirn