[PATCH 12/16] ntfs3: remove copy and pasted iomap code

[Christoph Hellwig <hch@lst.de>]

ntfs3 copied the iomap code without attribution or talking to the
maintainers, to hook into the bio completion for (unexplained) zeroing.

Fix this by just overriding the bio completion handler in the submit
handler.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/ntfs3/inode.c | 51 +++---------------------------------------------
 1 file changed, 3 insertions(+), 48 deletions(-)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index 7ab4e18f8013..60af9f8e0366 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -605,63 +605,18 @@ static void ntfs_iomap_read_end_io(struct bio *bio)
 	bio_put(bio);
 }
 
-/*
- * Copied from iomap/bio.c.
- */
-static int ntfs_iomap_bio_read_folio_range(const struct iomap_iter *iter,
-					   struct iomap_read_folio_ctx *ctx,
-					   size_t plen)
-{
-	struct folio *folio = ctx->cur_folio;
-	const struct iomap *iomap = &iter->iomap;
-	loff_t pos = iter->pos;
-	size_t poff = offset_in_folio(folio, pos);
-	loff_t length = iomap_length(iter);
-	sector_t sector;
-	struct bio *bio = ctx->read_ctx;
-
-	sector = iomap_sector(iomap, pos);
-	if (!bio || bio_end_sector(bio) != sector ||
-	    !bio_add_folio(bio, folio, plen, poff)) {
-		gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL);
-		gfp_t orig_gfp = gfp;
-		unsigned int nr_vecs = DIV_ROUND_UP(length, PAGE_SIZE);
-
-		if (bio)
-			submit_bio(bio);
-
-		if (ctx->rac) /* same as readahead_gfp_mask */
-			gfp |= __GFP_NORETRY | __GFP_NOWARN;
-		bio = bio_alloc(iomap->bdev, bio_max_segs(nr_vecs), REQ_OP_READ,
-				gfp);
-		/*
-		 * If the bio_alloc fails, try it again for a single page to
-		 * avoid having to deal with partial page reads.  This emulates
-		 * what do_mpage_read_folio does.
-		 */
-		if (!bio)
-			bio = bio_alloc(iomap->bdev, 1, REQ_OP_READ, orig_gfp);
-		if (ctx->rac)
-			bio->bi_opf |= REQ_RAHEAD;
-		bio->bi_iter.bi_sector = sector;
-		bio->bi_end_io = ntfs_iomap_read_end_io;
-		bio_add_folio_nofail(bio, folio, plen, poff);
-		ctx->read_ctx = bio;
-	}
-	return 0;
-}
-
 static void ntfs_iomap_bio_submit_read(const struct iomap_iter *iter,
 		struct iomap_read_folio_ctx *ctx)
 {
 	struct bio *bio = ctx->read_ctx;
 
+	bio->bi_end_io = ntfs_iomap_read_end_io;
 	submit_bio(bio);
 }
 
 static const struct iomap_read_ops ntfs_iomap_bio_read_ops = {
-	.read_folio_range = ntfs_iomap_bio_read_folio_range,
-	.submit_read = ntfs_iomap_bio_submit_read,
+	.read_folio_range	= iomap_bio_read_folio_range,
+	.submit_read		= ntfs_iomap_bio_submit_read,
 };
 
 static int ntfs_read_folio(struct file *file, struct folio *folio)
-- 
2.47.3