[PATCH v1 09/54] block: comment on bio_iov_iter_get_pages()

[Ming Lei]

bio_iov_iter_get_pages() used unused bvec spaces for
storing page pointer array temporarily, and this patch
comments on this usage wrt. multipage bvec support.

Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
---
 block/bio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/block/bio.c b/block/bio.c
index d4a1e0b63ea0..10398969353b 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -859,6 +859,10 @@ EXPORT_SYMBOL(bio_add_page);
  *
  * Pins as many pages from *iter and appends them to @bio's bvec array. The
  * pages will have to be released using put_page() when done.
+ *
+ * The hacking way of using bvec table as page pointer array is safe
+ * even after multipage bvec is introduced because that space can be
+ * thought as unused by bio_add_page().
  */
 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 {
-- 
2.7.4