[PATCH] sd: Disable support for 256 byte/sector disks

[PATCH] sd: Disable support for 256 byte/sector disks

[Hannes Reinecke]

256 bytes per sector support has been broken since 2.6.X,
and no-one stepped up to fix this.
So disable support for it.

Signed-off-by: Mark Hounschell <dmarkh@cfl.rr.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/sd.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 79beebf..7f9d65f 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1600,6 +1600,7 @@ static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
 {
 	u64 start_lba = blk_rq_pos(scmd->request);
 	u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512);
+	u64 factor = scmd->device->sector_size / 512;
 	u64 bad_lba;
 	int info_valid;
 	/*
@@ -1621,16 +1622,9 @@ static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
 	if (scsi_bufflen(scmd) <= scmd->device->sector_size)
 		return 0;
 
-	if (scmd->device->sector_size < 512) {
-		/* only legitimate sector_size here is 256 */
-		start_lba <<= 1;
-		end_lba <<= 1;
-	} else {
-		/* be careful ... don't want any overflows */
-		unsigned int factor = scmd->device->sector_size / 512;
-		do_div(start_lba, factor);
-		do_div(end_lba, factor);
-	}
+	/* be careful ... don't want any overflows */
+	do_div(start_lba, factor);
+	do_div(end_lba, factor);
 
 	/* The bad lba was reported incorrectly, we have no idea where
 	 * the error is.
@@ -2188,8 +2182,7 @@ got_data:
 	if (sector_size != 512 &&
 	    sector_size != 1024 &&
 	    sector_size != 2048 &&
-	    sector_size != 4096 &&
-	    sector_size != 256) {
+	    sector_size != 4096) {
 		sd_printk(KERN_NOTICE, sdkp, "Unsupported sector size %d.\n",
 			  sector_size);
 		/*
@@ -2244,8 +2237,6 @@ got_data:
 		sdkp->capacity <<= 2;
 	else if (sector_size == 1024)
 		sdkp->capacity <<= 1;
-	else if (sector_size == 256)
-		sdkp->capacity >>= 1;
 
 	blk_queue_physical_block_size(sdp->request_queue,
 				      sdkp->physical_block_size);
-- 
1.8.5.2

Re: [PATCH] sd: Disable support for 256 byte/sector disks

[Mark Hounschell]

On 05/13/2015 04:49 AM, Hannes Reinecke wrote:
> 256 bytes per sector support has been broken since 2.6.X,
> and no-one stepped up to fix this.
> So disable support for it.
>
> Signed-off-by: Mark Hounschell <dmarkh@cfl.rr.com>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>   drivers/scsi/sd.c | 19 +++++--------------
>   1 file changed, 5 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 79beebf..7f9d65f 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -1600,6 +1600,7 @@ static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
>   {
>   	u64 start_lba = blk_rq_pos(scmd->request);
>   	u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512);
> +	u64 factor = scmd->device->sector_size / 512;
>   	u64 bad_lba;
>   	int info_valid;
>   	/*
> @@ -1621,16 +1622,9 @@ static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
>   	if (scsi_bufflen(scmd) <= scmd->device->sector_size)
>   		return 0;
>
> -	if (scmd->device->sector_size < 512) {
> -		/* only legitimate sector_size here is 256 */
> -		start_lba <<= 1;
> -		end_lba <<= 1;
> -	} else {
> -		/* be careful ... don't want any overflows */
> -		unsigned int factor = scmd->device->sector_size / 512;
> -		do_div(start_lba, factor);
> -		do_div(end_lba, factor);
> -	}
> +	/* be careful ... don't want any overflows */
> +	do_div(start_lba, factor);
> +	do_div(end_lba, factor);
>
>   	/* The bad lba was reported incorrectly, we have no idea where
>   	 * the error is.
> @@ -2188,8 +2182,7 @@ got_data:
>   	if (sector_size != 512 &&
>   	    sector_size != 1024 &&
>   	    sector_size != 2048 &&
> -	    sector_size != 4096 &&
> -	    sector_size != 256) {
> +	    sector_size != 4096) {
>   		sd_printk(KERN_NOTICE, sdkp, "Unsupported sector size %d.\n",
>   			  sector_size);
>   		/*
> @@ -2244,8 +2237,6 @@ got_data:
>   		sdkp->capacity <<= 2;
>   	else if (sector_size == 1024)
>   		sdkp->capacity <<= 1;
> -	else if (sector_size == 256)
> -		sdkp->capacity >>= 1;
>
>   	blk_queue_physical_block_size(sdp->request_queue,
>   				      sdkp->physical_block_size);
>

Tested-by: Mark Hounschell <dmarkh@cfl.rr.com>

Mark

Re: [PATCH] sd: Disable support for 256 byte/sector disks

[James Bottomley]

On Wed, 2015-05-13 at 10:49 +0200, Hannes Reinecke wrote:
> 256 bytes per sector support has been broken since 2.6.X,
> and no-one stepped up to fix this.
> So disable support for it.

I assume this should have a 

From: Mark Hounschell <dmarkh@cfl.rr.com>

at the top?

James

Re: [PATCH] sd: Disable support for 256 byte/sector disks

[Hannes Reinecke]

On 05/13/2015 04:00 PM, James Bottomley wrote:
> On Wed, 2015-05-13 at 10:49 +0200, Hannes Reinecke wrote:
>> 256 bytes per sector support has been broken since 2.6.X,
>> and no-one stepped up to fix this.
>> So disable support for it.
> 
> I assume this should have a 
> 
> From: Mark Hounschell <dmarkh@cfl.rr.com>
> 
> at the top?
> 
> James
> 
I wasn't sure, as I've pulled the patch off bugzilla.
But do whatever you see fit.

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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Re: [PATCH] sd: Disable support for 256 byte/sector disks

[James Bottomley]

On Wed, 2015-05-13 at 16:09 +0200, Hannes Reinecke wrote:
> On 05/13/2015 04:00 PM, James Bottomley wrote:
> > On Wed, 2015-05-13 at 10:49 +0200, Hannes Reinecke wrote:
> >> 256 bytes per sector support has been broken since 2.6.X,
> >> and no-one stepped up to fix this.
> >> So disable support for it.
> > 
> > I assume this should have a 
> > 
> > From: Mark Hounschell <dmarkh@cfl.rr.com>
> > 
> > at the top?
> > 
> > James
> > 
> I wasn't sure, as I've pulled the patch off bugzilla.
> But do whatever you see fit.

It needs authorship (From: field) of whoever wrote it and put it on
bugzilla in the first place.  According to the entry, it was him:

https://bugzilla.kernel.org/show_bug.cgi?id=16058#c18

James

Re: [PATCH] sd: Disable support for 256 byte/sector disks

[Mark Hounschell]

On 05/13/2015 10:17 AM, James Bottomley wrote:
> On Wed, 2015-05-13 at 16:09 +0200, Hannes Reinecke wrote:
>> On 05/13/2015 04:00 PM, James Bottomley wrote:
>>> On Wed, 2015-05-13 at 10:49 +0200, Hannes Reinecke wrote:
>>>> 256 bytes per sector support has been broken since 2.6.X,
>>>> and no-one stepped up to fix this.
>>>> So disable support for it.
>>>
>>> I assume this should have a
>>>
>>> From: Mark Hounschell <dmarkh@cfl.rr.com>
>>>
>>> at the top?
>>>
>>> James
>>>
>> I wasn't sure, as I've pulled the patch off bugzilla.
>> But do whatever you see fit.
>
> It needs authorship (From: field) of whoever wrote it and put it on
> bugzilla in the first place.  According to the entry, it was him:
>
> https://bugzilla.kernel.org/show_bug.cgi?id=16058#c18
>

I am the author of that patch. What would you like me to do? My home 
email address is what I used in bugzilla "dmarkh@cfl.rr.com" years back 
when I originally submitted the bug. I'm sending this email from work.

I am Mark Hounschell and am the author of that patch and you can do with 
it whatever you see fit?

Regards
Mark