+static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
+{
+ const struct bio_vec *bv = iter->bvec;
+ unsigned int len;
+ size_t size;
+
+ if (WARN_ON_ONCE(iter->iov_offset > bv->bv_len))
+ return -EINVAL;
+
+ len = min_t(size_t, bv->bv_len - iter->iov_offset, iter->count);
+ size = bio_add_page(bio, bv->bv_page, len,
+ bv->bv_offset + iter->iov_offset);
+ if (size == len) {
+ struct page *page;
+ int i;
+
+ /*
+ * For the normal O_DIRECT case, we could skip grabbing this
+ * reference and then not have to put them again when IO
+ * completes. But this breaks some in-kernel users, like
+ * splicing to/from a loop device, where we release the pipe
+ * pages unconditionally. If we can fix that case, we can
+ * get rid of the get here and the need to call
+ * bio_release_pages() at IO completion time.
+ */
+ mp_bvec_for_each_page(page, bv, i)
+ get_page(page);
+ iov_iter_advance(iter, size);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+