From: jthumshirn@suse.de (Johannes Thumshirn)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] scsi: use sector_div instead of do_div
Date: Tue, 24 Nov 2015 13:48:59 +0100 [thread overview]
Message-ID: <1448369339.2877.30.camel@suse.de> (raw)
In-Reply-To: <24882658.08y4bWL6tn@wuerfel>
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;
> ?}
>
> --
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Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
next prev parent reply other threads:[~2015-11-24 12:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-20 16:38 [PATCH] scsi: use sector_div instead of do_div Arnd Bergmann
2015-11-24 12:48 ` Johannes Thumshirn [this message]
2015-11-24 12:50 ` Sagi Grimberg
2015-11-24 15:03 ` Hannes Reinecke
2015-11-26 3:28 ` Martin K. Petersen
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