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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
	Max Gurtovoy <maxg@mellanox.com>,
	axboe@kernel.dk, keith.busch@intel.com, sagi@grimberg.me,
	israelr@mellanox.com, linux-nvme@lists.infradead.org,
	linux-block@vger.kernel.org, shlomin@mellanox.com
Subject: Re: [PATCH v4 1/3] block: centralize PI remapping logic to the block layer
Date: Mon, 16 Sep 2019 13:19:51 -0400	[thread overview]
Message-ID: <yq17e68b1l4.fsf@oracle.com> (raw)
In-Reply-To: <20190916080328.GB25898@lst.de> (Christoph Hellwig's message of "Mon, 16 Sep 2019 10:03:28 +0200")


Christoph,

> Do we actually have Linux users of Type 3 at all?  I think for NVMe
> we could just trivially disable Linux support, and I suspect for SCSI
> as well, but I'll have to defer to you on that.

There were several companies looking into building Linux things using
Type 3 SCSI devices. No idea whether this happened. I definitely still
get lots of mail from people using Type 2. Something which also really
shouldn't exist outside of a disk array.

For NVMe, I assume nobody has tried Type 3 given the discrepancy between
how SCSI works and how the NVMe spec is currently written.

In any case. Since Type 3 is a pretty trivial subset of Type 1, I don't
see much benefit in actively removing it. One could argue we could
reduce the plumbing by removing a level of indirection. However, we'll
need the infrastructure to support the impending Type 4 as well. So my
preference is to just leave things as-is for now.

-- 
Martin K. Petersen	Oracle Linux Engineering

WARNING: multiple messages have this Message-ID (diff)
From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Christoph Hellwig <hch@lst.de>
Cc: axboe@kernel.dk, linux-block@vger.kernel.org, sagi@grimberg.me,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	israelr@mellanox.com, linux-nvme@lists.infradead.org,
	keith.busch@intel.com, shlomin@mellanox.com,
	Max Gurtovoy <maxg@mellanox.com>
Subject: Re: [PATCH v4 1/3] block: centralize PI remapping logic to the block layer
Date: Mon, 16 Sep 2019 13:19:51 -0400	[thread overview]
Message-ID: <yq17e68b1l4.fsf@oracle.com> (raw)
In-Reply-To: <20190916080328.GB25898@lst.de> (Christoph Hellwig's message of "Mon, 16 Sep 2019 10:03:28 +0200")


Christoph,

> Do we actually have Linux users of Type 3 at all?  I think for NVMe
> we could just trivially disable Linux support, and I suspect for SCSI
> as well, but I'll have to defer to you on that.

There were several companies looking into building Linux things using
Type 3 SCSI devices. No idea whether this happened. I definitely still
get lots of mail from people using Type 2. Something which also really
shouldn't exist outside of a disk array.

For NVMe, I assume nobody has tried Type 3 given the discrepancy between
how SCSI works and how the NVMe spec is currently written.

In any case. Since Type 3 is a pretty trivial subset of Type 1, I don't
see much benefit in actively removing it. One could argue we could
reduce the plumbing by removing a level of indirection. However, we'll
need the infrastructure to support the impending Type 4 as well. So my
preference is to just leave things as-is for now.

-- 
Martin K. Petersen	Oracle Linux Engineering

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  reply	other threads:[~2019-09-16 17:22 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-08 15:26 [PATCH v4 1/3] block: centralize PI remapping logic to the block layer Max Gurtovoy
2019-09-08 15:26 ` Max Gurtovoy
2019-09-08 15:26 ` [PATCH v4 2/3] block: don't remap ref tag for T10 PI type 0 Max Gurtovoy
2019-09-08 15:26   ` Max Gurtovoy
2019-09-09  2:22   ` Martin K. Petersen
2019-09-09  2:22     ` Martin K. Petersen
2019-09-09  2:36     ` Keith Busch
2019-09-09  2:36       ` Keith Busch
2019-09-09  2:49       ` Martin K. Petersen
2019-09-09  2:49         ` Martin K. Petersen
2019-09-09 13:31         ` Max Gurtovoy
2019-09-09 13:31           ` Max Gurtovoy
2019-09-08 15:26 ` [PATCH v4 3/3] nvme: remove PI values definition from NVMe subsystem Max Gurtovoy
2019-09-08 15:26   ` Max Gurtovoy
2019-09-09  2:21 ` [PATCH v4 1/3] block: centralize PI remapping logic to the block layer Martin K. Petersen
2019-09-09  2:21   ` Martin K. Petersen
2019-09-09 13:55   ` Max Gurtovoy
2019-09-09 13:55     ` Max Gurtovoy
2019-09-10  2:29     ` Martin K. Petersen
2019-09-10  2:29       ` Martin K. Petersen
2019-09-10 22:27       ` Max Gurtovoy
2019-09-10 22:27         ` Max Gurtovoy
2019-09-11  1:16         ` Martin K. Petersen
2019-09-11  1:16           ` Martin K. Petersen
2019-09-11  9:12           ` Max Gurtovoy
2019-09-11  9:12             ` Max Gurtovoy
2019-09-13 22:20             ` Martin K. Petersen
2019-09-13 22:20               ` Martin K. Petersen
2019-09-16  8:03               ` Christoph Hellwig
2019-09-16  8:03                 ` Christoph Hellwig
2019-09-16 17:19                 ` Martin K. Petersen [this message]
2019-09-16 17:19                   ` Martin K. Petersen

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