Re: [RFC PATCH v2 6/8] fs: add FMODE_CAN_DMABUF_IO and require it for dma-buf I/O contexts

[sashiko-bot@kernel.org]

> From: Mengmeng Zhao <zhaomengmeng@kylinos.cn>
> 
> Add a file mode bit for files that can be the target of dma-buf I/O and
> require it when a buffer is registered.  Block device files set it when
> the backing disk supports dma-buf I/O, and filesystems can set it for
> inodes whose data can be reached without the page cache.  The bit is
> coarse: a driver that installs ->init_dma_buf_io_ctx for every
> namespace, like nvme, still decides per device at registration.
> 
> dma_buf_io_ctx_create() is the only caller of ->init_dma_buf_io_ctx, so
> the capability and the O_DIRECT requirement are checked there for every
> file type rather than in each helper; O_DIRECT belongs at registration
> because F_SETFL can change it afterwards.  Add bdev_can_dmabuf_io() so
> the open-time and registration checks share one predicate.
> 
> Signed-off-by: Mengmeng Zhao <zhaomengmeng@kylinos.cn>
> Signed-off-by: Li Wang <liwang@kylinos.cn>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261113070621.273953-1-mengmeng.zhao@linux.dev?part=6