[PATCH] scsi: PC partition tables are little endian

[PATCH] scsi: PC partition tables are little endian

[Christoph Hellwig]

As sparse correctly pointed out scsi_partsize should use get_unaligned_le32
to read PC partition tables from disk, as they are little endian.

The result of this bug is that we returned incorrect geometries on big
endian systems when using the scsicam variant.  Which probably doesn't
matter as only old x86 systems every cared about the geometry.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsicam.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
index 92d24d6..910f4a7 100644
--- a/drivers/scsi/scsicam.c
+++ b/drivers/scsi/scsicam.c
@@ -163,8 +163,8 @@ int scsi_partsize(unsigned char *buf, unsigned long capacity,
 		    end_head * end_sector + end_sector;
 
 		/* This is the actual _sector_ number at the end */
-		logical_end = get_unaligned(&largest->start_sect)
-		    + get_unaligned(&largest->nr_sects);
+		logical_end = get_unaligned_le32(&largest->start_sect)
+		    + get_unaligned_le32(&largest->nr_sects);
 
 		/* This is for >1023 cylinders */
 		ext_cyl = (logical_end - (end_head * end_sector + end_sector))
-- 
1.9.1

Re: [PATCH] scsi: PC partition tables are little endian

[Christoph Hellwig]

ping?

On Wed, Oct 01, 2014 at 08:31:01PM +0200, Christoph Hellwig wrote:
> As sparse correctly pointed out scsi_partsize should use get_unaligned_le32
> to read PC partition tables from disk, as they are little endian.
> 
> The result of this bug is that we returned incorrect geometries on big
> endian systems when using the scsicam variant.  Which probably doesn't
> matter as only old x86 systems every cared about the geometry.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/scsi/scsicam.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
> index 92d24d6..910f4a7 100644
> --- a/drivers/scsi/scsicam.c
> +++ b/drivers/scsi/scsicam.c
> @@ -163,8 +163,8 @@ int scsi_partsize(unsigned char *buf, unsigned long capacity,
>  		    end_head * end_sector + end_sector;
>  
>  		/* This is the actual _sector_ number at the end */
> -		logical_end = get_unaligned(&largest->start_sect)
> -		    + get_unaligned(&largest->nr_sects);
> +		logical_end = get_unaligned_le32(&largest->start_sect)
> +		    + get_unaligned_le32(&largest->nr_sects);
>  
>  		/* This is for >1023 cylinders */
>  		ext_cyl = (logical_end - (end_head * end_sector + end_sector))
> -- 
> 1.9.1
> 
> --
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---end quoted text---

Re: [PATCH] scsi: PC partition tables are little endian

[Hannes Reinecke]

On 10/17/2014 03:13 PM, Christoph Hellwig wrote:
> ping?
>
> On Wed, Oct 01, 2014 at 08:31:01PM +0200, Christoph Hellwig wrote:
>> As sparse correctly pointed out scsi_partsize should use get_unaligned_le32
>> to read PC partition tables from disk, as they are little endian.
>>
>> The result of this bug is that we returned incorrect geometries on big
>> endian systems when using the scsicam variant.  Which probably doesn't
>> matter as only old x86 systems every cared about the geometry.
>>
>> Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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Re: [PATCH] scsi: PC partition tables are little endian

[Martin K. Petersen]

>>>>> "Christoph" == Christoph Hellwig <hch@infradead.org> writes:

>> As sparse correctly pointed out scsi_partsize should use
>> get_unaligned_le32 to read PC partition tables from disk, as they are
>> little endian.
>> 
>> The result of this bug is that we returned incorrect geometries on
>> big endian systems when using the scsicam variant.  Which probably
>> doesn't matter as only old x86 systems every cared about the
>> geometry.

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

-- 
Martin K. Petersen	Oracle Linux Engineering