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([2a01:4b00:bd21:4f00:7cc6:d3ca:494:116c]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48e412cc164sm31889960f8f.7.2026.10.29.03.53.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 29 Oct 2026 03:53:05 -0700 (PDT) Message-ID: <7fb73a55-c7f8-45bd-b12d-e46f1efcbe67@gmail.com> Date: Thu, 29 Oct 2026 10:53:07 +0000 X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 5/5] nvme: support dma-buf registered buffers for passthrough To: Anuj Gupta , axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, James.Bottomley@HansenPartnership.com, mkp@kernel.org, bernd@bsbernd.com, joannelkoong@gmail.com, miklos@szeredi.hu Cc: io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, fuse-devel@lists.linux.dev, joshi.k@samsung.com, anuj20.g@samsung.com References: <20261022144501.2478417-1-anuj1072538@gmail.com> <20261022144501.2478417-6-anuj1072538@gmail.com> Content-Language: en-US From: Pavel Begunkov In-Reply-To: <20261022144501.2478417-6-anuj1072538@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/22/26 15:44, Anuj Gupta wrote: > From: Anuj Gupta > > Allow registering a dma-buf against an NVMe namespace character device > and using it as the data buffer of fixed uring_cmd passthrough I/O. > Complete through io_uring_cmd_hw_done(), so the dma-buf map is released > at hardware completion. > > Signed-off-by: Anuj Gupta > --- > drivers/nvme/host/core.c | 16 ++++++++++++++++ > drivers/nvme/host/ioctl.c | 5 +++-- > 2 files changed, 19 insertions(+), 2 deletions(-) > > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c > index d81462e864a4..6157ff839929 100644 > --- a/drivers/nvme/host/core.c > +++ b/drivers/nvme/host/core.c > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -3982,6 +3983,20 @@ static int nvme_ns_chr_release(struct inode *inode, struct file *file) > return 0; > } > > +static int nvme_ns_chr_init_dma_buf_io_ctx(struct file *file, > + struct dma_buf_io_ctx *ctx) > +{ > + struct nvme_ns *ns = > + container_of(file_inode(file)->i_cdev, struct nvme_ns, cdev); > + struct nvme_ctrl *ctrl = ns->ctrl; > + > + if (ctx->dmabuf->size > UINT_MAX) > + return -EINVAL; > + if (!ctrl->ops->init_dma_buf_io_ctx) > + return -EINVAL; Let's return -EOPNOTSUPP for consistency, with that Reviewed-by: Pavel Begunkov -- Pavel Begunkov