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| Started by | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| First post | 2015-11-20 17:40 +0100 |
| Last post | 2015-11-26 04:40 +0100 |
| Articles | 5 — 5 participants |
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[PATCH] scsi: use sector_div instead of do_div Arnd Bergmann <arnd@arndb.de> - 2015-11-20 17:40 +0100
Re: [PATCH] scsi: use sector_div instead of do_div Johannes Thumshirn <jthumshirn@suse.de> - 2015-11-24 13:50 +0100
Re: [PATCH] scsi: use sector_div instead of do_div Sagi Grimberg <sagig@dev.mellanox.co.il> - 2015-11-24 14:00 +0100
Re: [PATCH] scsi: use sector_div instead of do_div Hannes Reinecke <hare@suse.de> - 2015-11-24 16:10 +0100
Re: [PATCH] scsi: use sector_div instead of do_div "Martin K. Petersen" <martin.petersen@oracle.com> - 2015-11-26 04:40 +0100
| From | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| Date | 2015-11-20 17:40 +0100 |
| Subject | [PATCH] scsi: use sector_div instead of do_div |
| Message-ID | <qwWT8-1dJ-25@gated-at.bofh.it> |
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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| From | Johannes Thumshirn <jthumshirn@suse.de> |
|---|---|
| Date | 2015-11-24 13:50 +0100 |
| Message-ID | <qylcK-8af-11@gated-at.bofh.it> |
| In reply to | #1274239 |
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>
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| From | Sagi Grimberg <sagig@dev.mellanox.co.il> |
|---|---|
| Date | 2015-11-24 14:00 +0100 |
| Message-ID | <qylmq-8dt-13@gated-at.bofh.it> |
| In reply to | #1274239 |
On 20/11/2015 18:38, 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> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Hannes Reinecke <hare@suse.de> |
|---|---|
| Date | 2015-11-24 16:10 +0100 |
| Message-ID | <qynoe-1lP-17@gated-at.bofh.it> |
| In reply to | #1274239 |
On 11/20/2015 05:38 PM, 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;
> }
>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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| From | "Martin K. Petersen" <martin.petersen@oracle.com> |
|---|---|
| Date | 2015-11-26 04:40 +0100 |
| Message-ID | <qyVzA-7ih-5@gated-at.bofh.it> |
| In reply to | #1274239 |
>>>>> "Arnd" == Arnd Bergmann <arnd@arndb.de> writes: Arnd> do_div is the wrong way to divide a sector_t, as it is less Arnd> efficient when sector_t is 32-bit wide. With the upcoming do_div Arnd> optimizations, the kernel starts warning about this: Applied. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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