+struct folio_vec {
+ struct folio *fv_folio;
+ size_t fv_offset;
+ size_t fv_len;
+};
+
+static inline struct folio_vec biovec_to_foliovec(struct bio_vec bv)
+{
+
+ struct folio *folio = page_folio(bv.bv_page);
+ size_t offset = (folio_page_idx(folio, bv.bv_page) << PAGE_SHIFT) +
+ bv.bv_offset;
+ size_t len = min_t(size_t, folio_size(folio) - offset, bv.bv_len);
+
+ return (struct folio_vec) {
+ .fv_folio = folio,
+ .fv_offset = offset,
+ .fv_len = len,
+ };
+}
+
+static inline struct folio_vec bio_iter_iovec_folio(struct bio *bio,
+ struct bvec_iter iter)
+{
+ return biovec_to_foliovec(bio_iter_iovec(bio, iter));
+}
+
+#define __bio_for_each_folio(bvl, bio, iter, start) \
+ for (iter = (start); \
+ (iter).bi_size && \
+ ((bvl = bio_iter_iovec_folio((bio), (iter))), 1); \
+ bio_advance_iter_single((bio), &(iter), (bvl).fv_len))
+
+/**
+ * bio_for_each_folio - iterate over folios within a bio
+ *
+ * Like other non-_all versions, this iterates over what bio->bi_iter currently
+ * points to. This version is for drivers, where the bio may have previously
+ * been split or cloned.
+ */
+#define bio_for_each_folio(bvl, bio, iter) \
+ __bio_for_each_folio(bvl, bio, iter, (bio)->bi_iter)
+
+/*
+ * Use u64 for the end pos and sector helpers because if the folio covers the
+ * max supported range of the mapping, the start offset of the next folio
+ * overflows loff_t. This breaks much of the range based processing in the
+ * buffered write path.
+ */
+static inline u64 folio_end_pos(struct folio *folio)
+{
+ return folio_pos(folio) + folio_size(folio);
+}
+
+static inline size_t folio_sectors(struct folio *folio)
+{
+ return PAGE_SECTORS << folio_order(folio);
+}
+
+static inline loff_t folio_sector(struct folio *folio)
+{
+ return folio_pos(folio) >> 9;
+}
+
+static inline u64 folio_end_sector(struct folio *folio)
+{
+ return folio_end_pos(folio) >> 9;
+}
+
+typedef DARRAY(struct folio *) folios;
+
+static int filemap_get_contig_folios_d(struct address_space *mapping,
+ loff_t start, u64 end,
+ int fgp_flags, gfp_t gfp,
+ folios *folios)
+{
+ struct folio *f;
+ u64 pos = start;
+ int ret = 0;
+
+ while (pos < end) {
+ if ((u64) pos >= (u64) start + (1ULL << 20))
+ fgp_flags &= ~FGP_CREAT;
+
+ ret = darray_make_room_gfp(folios, 1, gfp & GFP_KERNEL);
+ if (ret)
+ break;
+
+ f = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, fgp_flags, gfp);
+ if (IS_ERR_OR_NULL(f))
+ break;
+
+ BUG_ON(folios->nr && folio_pos(f) != pos);
+
+ pos = folio_end_pos(f);
+ darray_push(folios, f);
+ }
+
+ if (!folios->nr && !ret && (fgp_flags & FGP_CREAT))
+ ret = -ENOMEM;
+
+ return folios->nr ? 0 : ret;
+}
+