Unverified Commit b51d30ff authored by Brian Foster's avatar Brian Foster Committed by Christian Brauner
Browse files

iomap: export iomap_iter_advance() and return remaining length 



As a final step for generic iter advance, export the helper and
update it to return the remaining length of the current iteration
after the advance. This will usually be 0 in the iomap_iter() case,
but will be useful for the various operations that iterate on their
own and will be updated to advance as they progress.

Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
Link: https://lore.kernel.org/r/20250207143253.314068-7-bfoster@redhat.com


Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent b26f2ea1

fs/iomap/iter.c

+8 −14
Original line number Diff line number Diff line
@@ -15,22 +15,16 @@ static inline void iomap_iter_reset_iomap(struct iomap_iter *iter) 
}



/*

 * Advance to the next range we need to map.

 *

 * If the iomap is marked IOMAP_F_STALE, it means the existing map was not fully

 * processed - it was aborted because the extent the iomap spanned may have been

 * changed during the operation. In this case, the iteration behaviour is to

 * remap the unprocessed range of the iter, and that means we may need to remap

 * even when we've made no progress (i.e. count = 0). Hence the "finished

 * iterating" case needs to distinguish between (count = 0) meaning we are done

 * and (count = 0 && stale) meaning we need to remap the entire remaining range.

 * Advance the current iterator position and output the length remaining for the

 * current mapping.

 */

static inline int iomap_iter_advance(struct iomap_iter *iter, s64 count)

int iomap_iter_advance(struct iomap_iter *iter, u64 *count)

{

	if (WARN_ON_ONCE(count > iomap_length(iter)))

	if (WARN_ON_ONCE(*count > iomap_length(iter)))

		return -EIO;

	iter->pos += count;

	iter->len -= count;

	iter->pos += *count;

	iter->len -= *count;

	*count = iomap_length(iter);

	return 0;

}
@@ -93,7 +87,7 @@ int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops) 
	 * advanced at all (i.e. no work was done for some reason) unless the

	 * mapping has been marked stale and needs to be reprocessed.

	 */

	ret = iomap_iter_advance(iter, processed);

	ret = iomap_iter_advance(iter, &processed);

	if (!ret && iter->len > 0)

		ret = 1;

	if (ret > 0 && !iter->processed && !stale)

include/linux/iomap.h

+1 −0
Original line number Diff line number Diff line
@@ -236,6 +236,7 @@ struct iomap_iter { 
};



int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops);

int iomap_iter_advance(struct iomap_iter *iter, u64 *count);



/**

 * iomap_length_trim - trimmed length of the current iomap iteration