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Date: Thu, 9 Sep 2010 12:34:55 -0700 (PDT)
From: Anil kumar <anils_r@yahoo.com>
Subject: Re: scsi_cmnd data_buffer checksum
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christof Schmitt <christof.schmitt@de.ibm.com>,
        linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
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Martin,

Thanks. I will go thru the DIF document and code. 

But I had a quick question, isn't that drive has to support "protection enable" also. Also, does Controller FW need to do anything extra to send DIF block down to drive. Ideally we will be sending 512 byte blocks down to drive.

-Anil

--- On Thu, 9/9/10, Martin K. Petersen <martin.petersen@oracle.com> wrote:

> From: Martin K. Petersen <martin.petersen@oracle.com>
> Subject: Re: scsi_cmnd data_buffer checksum
> To: "Anil kumar" <anils_r@yahoo.com>
> Cc: "Christof Schmitt" <christof.schmitt@de.ibm.com>, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
> Date: Thursday, September 9, 2010, 9:23 AM
> >>>>> "Anil" == Anil
> kumar <anils_r@yahoo.com>
> writes:
> 
> Anil> cmd-> write_buf = (u8
> *)(kmap_atomic(sg->page, KM_IRQ0) + sg->offset);
> Anil> memcpy(cmd->local_write_buf, cmd->write_buf,
> cmd->scsibufflen(scsi_cmnd));
> 
> You need to walk the scatterlist.  You can't assume
> that the pages are
> contiguous in memory.
> 
> But why are you doing this checksumming stuff manually when
> the existing
> DIX/DIF code can do it for you?
> 
> -- 
> Martin K. Petersen    Oracle Linux
> Engineering
>