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:   Tue, 4 Dec 2018 23:33:55 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Robin Murphy <robin.murphy@arm.com>
Cc:     Christoph Hellwig <hch@lst.de>, iommu@lists.linux-foundation.org,
        linux-arch@vger.kernel.org, linux-alpha@vger.kernel.org,
        linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>, x86@kernel.org,
        linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org,
        David Woodhouse <dwmw2@infradead.org>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 01/23] dma-mapping: provide a generic DMA_MAPPING_ERROR
Message-ID: <20181204223355.GA12534@lst.de>
References: <20181130132231.16512-1-hch@lst.de> <20181130132231.16512-2-hch@lst.de> <653ca801-63a1-3c19-ee09-ade19fa2bbb8@arm.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <653ca801-63a1-3c19-ee09-ade19fa2bbb8@arm.com>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Dec 04, 2018 at 04:41:34PM +0000, Robin Murphy wrote:
> I'd have been inclined to put the default check here, i.e.
>
> -	return 0
> +	return dma_addr == DMA_MAPPING_ERROR
>
> such that the callback retains full precedence and we don't have to deal 
> with the non-trivial removals immediately if it comes to it. Not that it 
> makes a vast difference though, so either way,

Ok, I've switched it around.