iomap: stash iomap read ctx in the private field of iomap_iter

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It's useful to get filesystem-specific information using the
existing private field in the @iomap_iter passed to iomap_{begin,end}
for advanced usage for iomap buffered reads, which is much like the
current iomap DIO.

For example, EROFS needs it to:

 - implement an efficient page cache sharing feature, since iomap
   needs to apply to anon inode page cache but we'd like to get the
   backing inode/fs instead, so filesystem-specific private data is
   needed to keep such information;

 - pass in both struct page * and void * for inline data to avoid
   kmap_to_page() usage (which is bogus).

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://patch.msgid.link/20260109102856.598531-2-lihongbo22@huawei.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

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Hongbo Li 2026-01-09 10:28:47 +00:00 • committed by Christian Brauner

parent 8f0b4cce44

commit 8806f27924

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3 changed files with 10 additions and 8 deletions

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4

fs/fuse/file.c

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6

fs/iomap/buffered-io.c

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8

include/linux/iomap.h

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