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From: Matthew Wilcox <willy@linux.intel.com>
To: Keith Busch <keith.busch@intel.com>
Cc: "Jens Axboe" <axboe@fb.com>, "Matias Bjørling" <m@bjorling.me>,
	"sbradshaw@micron.com" <sbradshaw@micron.com>,
	"tom.leiming@gmail.com" <tom.leiming@gmail.com>,
	"hch@infradead.org" <hch@infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: Re: [PATCH v7] NVMe: conversion to blk-mq
Date: Tue, 10 Jun 2014 17:33:33 -0400	[thread overview]
Message-ID: <20140610213333.GA10055@linux.intel.com> (raw)
In-Reply-To: <alpine.LRH.2.03.1406101515430.4699@AMR>

On Tue, Jun 10, 2014 at 03:21:18PM -0600, Keith Busch wrote:
> Yeah, nvme_setup_prps is probably the least readable code in this driver.
> Maybe some comments are in order here...
> 
> There are two rules for an SGL to be mappable to a PRP:
> 
> 1. Every element must have zero page offset, except the first.
> 
> 2. Every element must end on a page boundary, except the last.

Or to put it another way, NVMe PRPs only support I/Os that describe a
single range of virtual memory.


  reply	other threads:[~2014-06-10 21:33 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-10  9:20 [PATCH v7] conversion to blk-mq Matias Bjørling
2014-06-10  9:20 ` [PATCH v7] NVMe: " Matias Bjørling
2014-06-10 15:51   ` Keith Busch
2014-06-10 16:19     ` Jens Axboe
2014-06-10 19:29       ` Keith Busch
2014-06-10 19:58         ` Jens Axboe
2014-06-10 21:10           ` Keith Busch
2014-06-10 21:14             ` Jens Axboe
2014-06-10 21:21               ` Keith Busch
2014-06-10 21:33                 ` Matthew Wilcox [this message]
2014-06-11 16:54                   ` Jens Axboe
2014-06-11 17:09                     ` Matthew Wilcox
2014-06-11 22:22                       ` Matias Bjørling
2014-06-11 22:51                         ` Keith Busch
2014-06-12 14:32                           ` Matias Bjørling
2014-06-12 16:24                             ` Keith Busch
2014-06-13  0:06                               ` Keith Busch
2014-06-13 14:07                                 ` Jens Axboe
2014-06-13 15:05                                   ` Keith Busch
2014-06-13 15:11                                     ` Jens Axboe
2014-06-13 15:16                                       ` Keith Busch
2014-06-13 18:14                                         ` Jens Axboe
2014-06-13 19:22                                           ` Keith Busch
2014-06-13 19:29                                             ` Jens Axboe
2014-06-13 20:56                                               ` Jens Axboe
2014-06-13 21:28                                             ` Jens Axboe

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