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AJvYcCVlhsecCmiJzK5eEpBJDcBxu5pL+co8hblHL4qbTpdcEyVATYHPV/WlsALfRZOalsc7pRZwk8oggQ==@kvack.org X-Gm-Message-State: AOJu0Yz1x0lQarc5o8LSrI9dchD7CKl3slftPSSXHF3UHOogDwJ+NsJ+ 5uYces0PexGCzRLg2qpn2/sal1NqyG2wl8GrAhq396DGZGjnQZTt8XLG5xCxFfb7+bBdTD7TVGf cPScKmEnpFZjXSL5pPCmWLYTTOSs= X-Google-Smtp-Source: AGHT+IGCJWVGSDxh88mmV8TfpUkds1GTcb/SQfLMvdY+xjmMgOtiWhJjm3URTLzGgKvmaZLyg2QvEHBS9bNI0FtRaqQ= X-Received: by 2002:a05:651c:881:b0:2fb:6465:3183 with SMTP id 38308e7fff4ca-2ff201e7398mr46022501fa.3.1731294836895; Sun, 10 Nov 2024 19:13:56 -0800 (PST) MIME-Version: 1.0 References: <875xouv5lt.fsf@trenco.lwn.net> In-Reply-To: <875xouv5lt.fsf@trenco.lwn.net> From: anish kumar Date: Sun, 10 Nov 2024 19:13:45 -0800 Message-ID: Subject: Re: [PATCH v3 09/17] docs: core-api: document the IOVA-based API To: Jonathan Corbet Cc: Leon Romanovsky , Jens Axboe , Jason Gunthorpe , Robin Murphy , Joerg Roedel , Will Deacon , Christoph Hellwig , Sagi Grimberg , Keith Busch , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , Marek Szyprowski , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Randy Dunlap Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: 51uyijoe15otu8jinokaa5ixpf1eanqc X-Rspamd-Queue-Id: BF67180005 X-Rspamd-Server: rspam08 X-Rspam-User: X-HE-Tag: 1731294763-353848 X-HE-Meta: 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 Jj4fnqzO 2ClFGvti1UIgMluJy/ZsDshpVEJreOkBI+/7iRXZwKbRLgvecTNuF5U5U/nB/l4ki7CNH5bE2OFCi0byz3YtO/6YGPf+kqz8dnlIs5CkhCqiAUFHTnb4PzxuwpkyrojXElTV4NC4MWvuibyBZAUW9KBQVF2DUy969IEQ/QHcmV9h3MShOJ1NEX8SdalBGPY7yuRSAQ7tDQHWRi6ozJu1GvM4b7pLGNvK93B8NETXLFJTBScXRNQ0mVTdQeUXCmAhpkotwr6Rb4vgpBGflvJWMj+5zg6v05JzLPr0p3HG5XPV3njHjHfRWLul5Oqw3N+7HpnctDHOsfzzVmDSXEquUVQjgx3/B17mm26RYxCK2eTVz1Oh0MLJdtyZUTCP2kuVEXICQp3sgDTRKox5DG4t+EigX6pQo7dhQdmzmVad4dor2DkbOvjEvtH7qPyI9r+dOmZC8 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, Nov 10, 2024 at 6:58=E2=80=AFPM Jonathan Corbet wr= ote: > > anish kumar writes: > > > On Sun, Nov 10, 2024 at 5:50=E2=80=AFAM Leon Romanovsky wrote: > >> > >> From: Christoph Hellwig > >> > >> Add an explanation of the newly added IOVA-based mapping API. > >> > >> Signed-off-by: Christoph Hellwig > >> Signed-off-by: Leon Romanovsky > >> --- > >> Documentation/core-api/dma-api.rst | 70 +++++++++++++++++++++++++++++= + > >> 1 file changed, 70 insertions(+) > >> > >> diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-a= pi/dma-api.rst > >> index 8e3cce3d0a23..61d6f4fe3d88 100644 > >> --- a/Documentation/core-api/dma-api.rst > >> +++ b/Documentation/core-api/dma-api.rst > >> @@ -530,6 +530,76 @@ routines, e.g.::: > >> .... > >> } > >> > >> +Part Ie - IOVA-based DMA mappings > >> +--------------------------------- > >> + > >> +These APIs allow a very efficient mapping when using an IOMMU. They = are an > > > > "They" doesn't sound nice. > >> +optional path that requires extra code and are only recommended for d= rivers > >> +where DMA mapping performance, or the space usage for storing the DMA= addresses > >> +matter. All the considerations from the previous section apply here = as well. > > > > These APIs provide an efficient mapping when using an IOMMU. However, t= hey > > are optional and require additional code. They are recommended primaril= y for > > drivers where performance in DMA mapping or the storage space for DMA > > addresses are critical. All the considerations discussed in the previou= s section > > also apply in this case. > > > > You can disregard this comment, as anyone reading this paragraph will > > understand the intended message. > > I don't understand the comment, honestly. You say "they" doesn't "sound > nice", whatever that means, but your suggestion retains the "they"...? > > I'm all for reviews that improve our documentation, but it is > *incredibly* easy to fall into the trivial bikeshed mode. I've > certainly done it myself. The end result is less documentation as > people decide, understandably, that it's not worth the pain. Hopefully > we can all try to do a bit less of that. > > FWIW, I think the paragraph is fine as written. I completely agree, and that's why I suggested feeling free to disregard the comment. When I read it, I felt it could be improved, but I agree=E2=80=94there's no point in overanalyzing it. > > Thanks, > > jon