From: sashiko-bot@kernel.org
To: "Mengmeng Zhao" <mengmeng.zhao@linux.dev>
Cc: linux-ext4@vger.kernel.org, tytso@mit.edu
Subject: Re: [RFC PATCH v2 3/8] iomap: don't ask for a buffered fallback for dma-buf iterators
Date: Fri, 13 Nov 2026 07:28:27 +0000 [thread overview]
Message-ID: <sashiko-outbox-212349@kernel.org> (raw)
In-Reply-To: <20261113070621.273953-4-mengmeng.zhao@linux.dev>
> From: Mengmeng Zhao <zhaomengmeng@kylinos.cn>
>
> -ENOTBLK tells the caller to retry with buffered I/O. A dma-buf iterator
> has no pages to copy, so the callers refuse that fallback, which would
> turn the error into a successful transfer of zero bytes.
>
> Report the reason instead: a busy folio becomes -EAGAIN, which the caller
> can retry, any other invalidation failure keeps its error code, and
> -ENOTBLK from ->iomap_begin() becomes -EOPNOTSUPP when nothing was
> transferred. A partial direct I/O still reports its progress. Both
> branches are reachable only through a file that opted into dma-buf I/O,
> which ext4 does in the last patch.
>
> 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.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261113070621.273953-1-mengmeng.zhao@linux.dev?part=3
next prev parent reply other threads:[~2026-11-13 7:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-13 7:06 [RFC PATCH v2 0/8] ext4: Add dma-buf read/write support Mengmeng Zhao
2026-11-13 7:06 ` [RFC PATCH v2 1/8] block: factor out bdev_init_dma_buf_io_ctx() Mengmeng Zhao
2026-11-13 7:24 ` sashiko-bot
2026-11-13 7:06 ` [RFC PATCH v2 2/8] iomap: add dma-buf direct I/O guards Mengmeng Zhao
2026-11-13 7:31 ` sashiko-bot
2026-11-13 7:06 ` [RFC PATCH v2 3/8] iomap: don't ask for a buffered fallback for dma-buf iterators Mengmeng Zhao
2026-11-13 7:28 ` sashiko-bot [this message]
2026-11-13 7:06 ` [RFC PATCH v2 4/8] blk-mq: factor out a dma-buf bio refusal helper Mengmeng Zhao
2026-11-13 7:12 ` sashiko-bot
2026-11-13 7:06 ` [RFC PATCH v2 5/8] blk-crypto: refuse dma-buf bios in the fallback path Mengmeng Zhao
2026-11-13 7:24 ` sashiko-bot
2026-11-13 7:06 ` [RFC PATCH v2 6/8] fs: add FMODE_CAN_DMABUF_IO and require it for dma-buf I/O contexts Mengmeng Zhao
2026-11-13 7:24 ` sashiko-bot
2026-11-13 7:06 ` [RFC PATCH v2 7/8] dax: refuse dma-buf iterators in dax_iomap_rw() Mengmeng Zhao
2026-11-13 7:25 ` sashiko-bot
2026-11-13 7:06 ` [RFC PATCH v2 8/8] ext4: support dma-buf registered buffers for direct I/O Mengmeng Zhao
2026-11-13 7:26 ` sashiko-bot
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