lkml.org 
[lkml]   [2015]   [Nov]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] scsi: use sector_div instead of do_div
From
Date
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 <arnd@arndb.de>
> ---
> 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 <jthumshirn@suse.de>


\
 
 \ /
  Last update: 2015-11-24 14:01    [W:0.071 / U:0.352 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site