iomap: push non-large folio check into get folio path

The len param to __iomap_get_folio() is primarily a folio allocation
hint. iomap_write_begin() already trims its local len variable based
on the provided folio, so move the large folio support check closer
to folio lookup.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Link: https://lore.kernel.org/20250506134118.911396-6-bfoster@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 01b9e0cbabf2050cdc8aa0a7ac397b2f3e4318b0..86482b84825999fd66e0fcd9fa711826096a2cba 100644 (file)
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -746,6 +746,9 @@ static struct folio *__iomap_get_folio(struct iomap_iter *iter, size_t len)
        const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops;
        loff_t pos = iter->pos;
 
+       if (!mapping_large_folio_support(iter->inode->i_mapping))
+               len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos));
+
        if (folio_ops && folio_ops->get_folio)
                return folio_ops->get_folio(iter, pos, len);
        else
@@ -807,9 +810,6 @@ static int iomap_write_begin(struct iomap_iter *iter, size_t len,
        if (fatal_signal_pending(current))
                return -EINTR;
 
-       if (!mapping_large_folio_support(iter->inode->i_mapping))
-               len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos));
-
        folio = __iomap_get_folio(iter, len);
        if (IS_ERR(folio))
                return PTR_ERR(folio);