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Date:   Fri, 29 Jan 2021 02:34:51 +0900
From:   Keith Busch <kbusch@kernel.org>
To:     Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc:     Jianxiong Gao <jxgao@google.com>, erdemaktas@google.com,
        marcorr@google.com, hch@lst.de, m.szyprowski@samsung.com,
        robin.murphy@arm.com, gregkh@linuxfoundation.org,
        saravanak@google.com, heikki.krogerus@linux.intel.com,
        rafael.j.wysocki@intel.com, andriy.shevchenko@linux.intel.com,
        dan.j.williams@intel.com, bgolaszewski@baylibre.com,
        jroedel@suse.de, iommu@lists.linux-foundation.org, axboe@fb.com,
        sagi@grimberg.me, linux-nvme@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] Add swiotlb offset preserving mapping when
 dma_dma_parameters->page_offset_mask is non zero.
Message-ID: <20210128173451.GA31631@redsun51.ssa.fujisawa.hgst.com>
References: <20210128003829.1892018-1-jxgao@google.com>
 <20210128003829.1892018-3-jxgao@google.com>
 <YBLxMP3sr71BTL+d@Konrads-MacBook-Pro.local>
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On Thu, Jan 28, 2021 at 12:15:28PM -0500, Konrad Rzeszutek Wilk wrote:
> On Wed, Jan 27, 2021 at 04:38:28PM -0800, Jianxiong Gao wrote:
> > For devices that need to preserve address offset on mapping through
> > swiotlb, this patch adds offset preserving based on page_offset_mask
> > and keeps the offset if the mask is non zero. This is needed for
> > device drivers like NVMe.
> 
> <scratches his head>
> 
> Didn't you send this patch like a month ago and someone pointed
> out that the right fix would be in the NVMe driver?
> 
> Is there an issue with fixing the NVMe driver?

You got it backwards. The initial "fix" used a flag specific to the nvme
driver, and it was pointed out that it should just be the generic
behaviour.