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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-scsi@vger.kernel.org
Subject: Re: [PATCH 04 of 10] scsi: Support devices with protection information (DIF)
Date: Mon, 30 Jun 2008 11:24:35 -0400	[thread overview]
Message-ID: <yq17ic7c5e4.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <1214665658.3658.18.camel@localhost.localdomain> (James Bottomley's message of "Sat\, 28 Jun 2008 10\:07\:38 -0500")

>>>>> "James" == James Bottomley <James.Bottomley@HansenPartnership.com> writes:

[Protection sgl alloc + init]

James> I'm afraid you can't do it like this because it will violate
James> our forward progress guarantees.  If this is the last spare
James> command required for writeout, you need to guarantee either
James> this allocation will succeed, or we can proceed without the DIF
James> data.

We can't just turn off DIF -- that would violate the integrity
guarantees.  But I'll move the protection sgl to the host command
pool.



>> + if (inq_result[5] & 0x1) + sdev->protection = 1;

James> Is there a reason to have a separate flag here

Not really.  I used to key off of sdp->protection quite a bit but I
think the only place I use it now is during sd discovery.  So this can
simply go away...

-- 
Martin K. Petersen	Oracle Linux Engineering


  reply	other threads:[~2008-06-30 15:24 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-25 15:22 [PATCH 00 of 10] SCSI Data Integrity Support Martin K. Petersen
2008-06-25 15:22 ` [PATCH 01 of 10] sd: Move sd.h header file Martin K. Petersen
2008-06-25 15:22 ` [PATCH 02 of 10] sd: Move scsi_disk() accessor function to sd.h Martin K. Petersen
2008-06-25 15:22 ` [PATCH 03 of 10] lib: Add support for the T10 Data Integrity Field CRC Martin K. Petersen
2008-06-25 15:22 ` [PATCH 04 of 10] scsi: Support devices with protection information (DIF) Martin K. Petersen
2008-06-28 15:07   ` James Bottomley
2008-06-30 15:24     ` Martin K. Petersen [this message]
2008-06-25 15:22 ` [PATCH 05 of 10] scsi: Host protection capabilities Martin K. Petersen
2008-06-25 15:22 ` [PATCH 06 of 10] scsi: Command protection operation Martin K. Petersen
2008-06-25 15:22 ` [PATCH 07 of 10] scsi: Do not retry a request whose data integrity check failed Martin K. Petersen
2008-06-25 15:22 ` [PATCH 08 of 10] scsi: Documentation for the SCSI protection information/DIF support Martin K. Petersen
2008-06-25 15:22 ` [PATCH 09 of 10] sd: Identify DIF protection type and application tag ownership Martin K. Petersen
2008-06-25 15:22 ` [PATCH 10 of 10] sd: Support for SCSI disk (SBC) Data Integrity Field Martin K. Petersen

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