| Message ID | 20250205135821.178256-7-bfoster@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | iomap: incremental per-operation iter advance | expand |
On Wed, Feb 05, 2025 at 08:58:17AM -0500, Brian Foster wrote: > 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: Brian Foster <bfoster@redhat.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> > --- > fs/iomap/iter.c | 22 ++++++++-------------- > include/linux/iomap.h | 1 + > 2 files changed, 9 insertions(+), 14 deletions(-) > > diff --git a/fs/iomap/iter.c b/fs/iomap/iter.c > index 8e0746ad80bd..cdba24dbbfd7 100644 > --- a/fs/iomap/iter.c > +++ b/fs/iomap/iter.c > @@ -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 return the length remaining for the > + * current mapping. This last sentence should state that the remaining length is returned via @count as an outparam and not through the function's return value. Otherwise looks ok to me. --D > */ > -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) > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index f5ca71ac2fa2..f304c602e5fe 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -229,6 +229,7 @@ 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 > -- > 2.48.1 > >
diff --git a/fs/iomap/iter.c b/fs/iomap/iter.c index 8e0746ad80bd..cdba24dbbfd7 100644 --- a/fs/iomap/iter.c +++ b/fs/iomap/iter.c @@ -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 return 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) diff --git a/include/linux/iomap.h b/include/linux/iomap.h index f5ca71ac2fa2..f304c602e5fe 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -229,6 +229,7 @@ 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