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Thu, 13 Nov 2025 12:40:53 -0800 (PST) Message-ID: Date: Thu, 13 Nov 2025 13:40:50 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 0/2] block: Enable proper MMIO memory handling for P2P DMA To: Keith Busch Cc: Christoph Hellwig , Sagi Grimberg , Leon Romanovsky , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org References: <20251112-block-with-mmio-v4-0-54aeb609d28d@nvidia.com> <176305197986.133468.1935881415989157155.b4-ty@kernel.dk> <4f75497d-11cb-437c-ab90-d65d4d2e0a52@kernel.dk> Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/13/25 12:52 PM, Keith Busch wrote: > On Thu, Nov 13, 2025 at 10:45:53AM -0700, Jens Axboe wrote: >> I took a look, and what happens here is that iter.p2pdma.map is 0 as it >> never got set to anything. That is the same as PCI_P2PDMA_MAP_UNKNOWN, >> and hence we just end up in a BLK_STS_RESOURCE. First of all, returning >> BLK_STS_RESOURCE for that seems... highly suspicious. That should surely >> be a fatal error. And secondly, this just further backs up that there's >> ZERO testing done on this patchset at all. WTF? >> >> FWIW, the below makes it boot just fine, as expected, as a default zero >> filled iter then matches the UNKNOWN case. > > I think this must mean you don't have CONFIG_PCI_P2PDMA enabled. The Right, like most normal people :-) > state is never set in that case, but I think it should have been. If you want the patchset to boot, yes it should have been... -- Jens Axboe