Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
To:     Christoph Hellwig <hch@lst.de>, Jason Gunthorpe <jgg@ziepe.ca>
Cc:     linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
        linux-block@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-mm@kvack.org, iommu@lists.linux-foundation.org,
        Stephen Bates <sbates@raithlin.com>,
        Dan Williams <dan.j.williams@intel.com>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Don Dutile <ddutile@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Jakowski Andrzej <andrzej.jakowski@intel.com>,
        Minturn Dave B <dave.b.minturn@intel.com>,
        Jason Ekstrand <jason@jlekstrand.net>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Xiong Jianxin <jianxin.xiong@intel.com>,
        Bjorn Helgaas <helgaas@kernel.org>,
        Ira Weiny <ira.weiny@intel.com>,
        Robin Murphy <robin.murphy@arm.com>
References: <20210408170123.8788-1-logang@deltatee.com>
 <20210408170123.8788-6-logang@deltatee.com>
 <20210427193157.GQ2047089@ziepe.ca>
 <3c9ba6df-750a-3847-f1fc-8e41f533d1a2@deltatee.com>
 <20210427230113.GV2047089@ziepe.ca> <20210503182811.GC17174@lst.de>
From:   Logan Gunthorpe <logang@deltatee.com>
Message-ID: <e3d55333-1e24-8dad-4a94-727bce8f776c@deltatee.com>
Date:   Mon, 3 May 2021 12:31:03 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.9.0
MIME-Version: 1.0
In-Reply-To: <20210503182811.GC17174@lst.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-CA
Content-Transfer-Encoding: 7bit
Subject: Re: [PATCH 05/16] dma-mapping: Introduce dma_map_sg_p2pdma()
Precedence: bulk


On 2021-05-03 12:28 p.m., Christoph Hellwig wrote:
> On Tue, Apr 27, 2021 at 08:01:13PM -0300, Jason Gunthorpe wrote:
>> At a high level I'm OK with it. dma_map_sg_attrs() is the extra
>> extended version of dma_map_sg(), it already has a different
>> signature, a different return code is not out of the question.
>>
>> dma_map_sg() is just the simple easy to use interface that can't do
>> advanced stuff.
>>
>>> I'm not that opposed to this. But it will make this series a fair bit
>>> longer to change the 8 map_sg_attrs() usages.
>>
>> Yes, but the result seems much nicer to not grow the DMA API further.
> 
> We already have a mapping function that can return errors:
> dma_map_sgtable.
> 
> I think it might make more sense to piggy back on that, as the sg_table
> abstraction is pretty useful basically everywhere that we deal with
> scatterlists anyway.

Oh, I didn't even realize that existed. I'll use dma_map_sgtable() for v2.

Thanks,

Logan