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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Cc: JBottomley@Parallels.com, jejb@kernel.org, hch@infradead.org,
	martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
	Sathya.Prakash@broadcom.com, kashyap.desai@broadcom.com,
	linux-kernel@vger.kernel.org, chaitra.basappa@broadcom.com,
	sreekanth.reddy@broadcom.com, linux-nvme@lists.infradead.org
Subject: Re: [PATCH v3 03/13] mpt3sas: SGL to PRP Translation for I/Os to NVMe  devices
Date: Tue, 08 Aug 2017 12:12:13 -0400	[thread overview]
Message-ID: <yq1o9rq6ntu.fsf@oracle.com> (raw)
In-Reply-To: <1502183035-7441-4-git-send-email-suganath-prabu.subramani@broadcom.com> (Suganath Prabu S.'s message of "Tue, 8 Aug 2017 14:33:45 +0530")


Suganath,

> +	/*
> +	 ** Below code detects gaps/holes in IO data buffers.
> +	 ** What does holes/gaps mean?
> +	 ** Any SGE except first one in a SGL starts at non NVME page size
> +	 ** aligned address OR Any SGE except last one in a SGL ends at
> +	 ** non NVME page size boundary.
> +	 **
> +	 ** Driver has already informed block layer by setting boundary rules
> +	 ** for bio merging done at NVME page size boundary calling kernel API
> +	 ** blk_queue_virt_boundary inside slave_config.
> +	 ** Still there is possibility of IO coming with holes to driver because
> +	 ** of IO merging done by IO scheduler.

All this SGL to PRP code needs to go.

If you are seeing anything that's not a valid PRP after setting the
queue virt boundary then there's a block layer bug that needs to be
debugged and fixed. Regardless of whether you are using an I/O scheduler
or not.

-- 
Martin K. Petersen	Oracle Linux Engineering

WARNING: multiple messages have this Message-ID (diff)
From: martin.petersen@oracle.com (Martin K. Petersen)
Subject: [PATCH v3 03/13] mpt3sas: SGL to PRP Translation for I/Os to NVMe devices
Date: Tue, 08 Aug 2017 12:12:13 -0400	[thread overview]
Message-ID: <yq1o9rq6ntu.fsf@oracle.com> (raw)
In-Reply-To: <1502183035-7441-4-git-send-email-suganath-prabu.subramani@broadcom.com> (Suganath Prabu S.'s message of "Tue, 8 Aug 2017 14:33:45 +0530")


Suganath,

> +	/*
> +	 ** Below code detects gaps/holes in IO data buffers.
> +	 ** What does holes/gaps mean?
> +	 ** Any SGE except first one in a SGL starts at non NVME page size
> +	 ** aligned address OR Any SGE except last one in a SGL ends at
> +	 ** non NVME page size boundary.
> +	 **
> +	 ** Driver has already informed block layer by setting boundary rules
> +	 ** for bio merging done at NVME page size boundary calling kernel API
> +	 ** blk_queue_virt_boundary inside slave_config.
> +	 ** Still there is possibility of IO coming with holes to driver because
> +	 ** of IO merging done by IO scheduler.

All this SGL to PRP code needs to go.

If you are seeing anything that's not a valid PRP after setting the
queue virt boundary then there's a block layer bug that needs to be
debugged and fixed. Regardless of whether you are using an I/O scheduler
or not.

-- 
Martin K. Petersen	Oracle Linux Engineering

  reply	other threads:[~2017-08-08 16:13 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-08  9:03 [PATCH v3 00/13] mpt3sas driver NVMe support: Suganath Prabu S
2017-08-08  9:03 ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 01/13] mpt3sas: Update MPI Header Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08 21:18   ` J Freyensee
2017-08-08 21:18     ` J Freyensee
2017-08-21  5:54     ` Suganath Prabu Subramani
2017-08-21  5:54       ` Suganath Prabu Subramani
2017-08-08  9:03 ` [PATCH v3 02/13] mpt3sas: Add nvme device support in slave alloc, target alloc and probe Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 03/13] mpt3sas: SGL to PRP Translation for I/Os to NVMe devices Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08 16:12   ` Martin K. Petersen [this message]
2017-08-08 16:12     ` Martin K. Petersen
2017-08-09 12:37     ` Suganath Prabu Subramani
2017-08-09 12:37       ` Suganath Prabu Subramani
2017-08-08  9:03 ` [PATCH v3 04/13] mpt3sas: Added support for nvme encapsulated request message Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 05/13] mpt3sas: API 's to support NVMe drive addition to SML Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 06/13] mpt3sas: API's to remove nvme drive from sml Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 07/13] mpt3sas: Handle NVMe PCIe device related events generated from firmware Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 08/13] mpt3sas: Set NVMe device queue depth as 128 Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 09/13] mpt3sas: scan and add nvme device after controller reset Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 10/13] mpt3as: Add-Task-management-debug-info-for-NVMe-drives Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 11/13] mpt3sas: NVMe drive support for BTDHMAPPING ioctl command and log info Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 12/13] mpt3sas: Fix nvme drives checking for tlr Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S
2017-08-08  9:03 ` [PATCH v3 13/13] mpt3sas: Update mpt3sas driver version Suganath Prabu S
2017-08-08  9:03   ` Suganath Prabu S

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