Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 9 Oct 2019 08:51:15 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Lu Baolu <baolu.lu@linux.intel.com>
Cc:     Arvind Sankar <nivedita@alum.mit.edu>,
        linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] iommu/vt-d: Return the correct dma mask when we are
 bypassing the IOMMU
Message-ID: <20191009065115.GB30157@lst.de>
References: <20191008143357.GA599223@rani.riverdale.lan> <76d680ab-a454-4a69-597a-c0edbfc5014b@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <76d680ab-a454-4a69-597a-c0edbfc5014b@linux.intel.com>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Oct 09, 2019 at 10:45:15AM +0800, Lu Baolu wrote:
> Do you mind explaining why we always return 32 bit here?

See the comment in dma_get_required_mask().