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Tsirkin" , Miguel Ojeda , Robin Murphy , rust-for-linux@vger.kernel.org, Sagi Grimberg , Stefano Stabellini , Steven Rostedt , virtualization@lists.linux.dev, Will Deacon , xen-devel@lists.xenproject.org Subject: Re: [PATCH v4 15/16] block-dma: properly take MMIO path Message-ID: References: <642dbeb7aa94257eaea71ec63c06e3f939270023.1755624249.git.leon@kernel.org> <20250828165427.GB10073@unreal> <20250828184115.GE7333@nvidia.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250828184115.GE7333@nvidia.com> On Thu, Aug 28, 2025 at 03:41:15PM -0300, Jason Gunthorpe wrote: > On Thu, Aug 28, 2025 at 11:15:20AM -0600, Keith Busch wrote: > > > > I don't think that was ever the case. Metadata is allocated > > independently of the data payload, usually by the kernel in > > bio_integrity_prep() just before dispatching the request. The bio may > > have a p2p data payload, but the integrity metadata is just a kmalloc > > buf in that path. > > Then you should do two dma mapping operations today, that is how the > API was built. You shouldn't mix P2P and non P2P within a single > operation right now.. Data and metadata are mapped as separate operations. They're just different parts of one blk-mq request.