btrfs: simplify subpage handling of read_extent_buffer_pages_nowait()

By using a shared bio_add_folio_nofail() with calculated
range_start/range_len, so no more explicit subpage routine needed.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 8 insertions, 13 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b23d27cfdf146..1deff394ead3f 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3494,8 +3494,8 @@ static void end_bbio_meta_read(struct btrfs_bio *bbio)
 int read_extent_buffer_pages_nowait(struct extent_buffer *eb, int mirror_num,
 				    const struct btrfs_tree_parent_check *check)
 {
+	const int num_folios = num_extent_folios(eb);
 	struct btrfs_bio *bbio;
-	bool ret;
 
 	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
 		return 0;
@@ -3535,19 +3535,14 @@ int read_extent_buffer_pages_nowait(struct extent_buffer *eb, int mirror_num,
 	bbio->inode = BTRFS_I(eb->fs_info->btree_inode);
 	bbio->file_offset = eb->start;
 	memcpy(&bbio->parent_check, check, sizeof(*check));
-	if (btrfs_meta_is_subpage(eb->fs_info)) {
-		ret = bio_add_folio(&bbio->bio, eb->folios[0], eb->len,
-				    eb->start - folio_pos(eb->folios[0]));
-		ASSERT(ret);
-	} else {
-		int num_folios = num_extent_folios(eb);
-
-		for (int i = 0; i < num_folios; i++) {
-			struct folio *folio = eb->folios[i];
+	for (int i = 0; i < num_folios; i++) {
+		struct folio *folio = eb->folios[i];
+		u64 range_start = max_t(u64, eb->start, folio_pos(folio));
+		u32 range_len = min_t(u64, folio_pos(folio) + folio_size(folio),
+				      eb->start + eb->len) - range_start;
 
-			ret = bio_add_folio(&bbio->bio, folio, eb->folio_size, 0);
-			ASSERT(ret);
-		}
+		bio_add_folio_nofail(&bbio->bio, folio, range_len,
+				     offset_in_folio(folio, range_start));
 	}
 	btrfs_submit_bbio(bbio, mirror_num);
 	return 0;