[PATCH v2 09/51] block: comment on bio_iov_iter_get_pages()

Ming Lei
2017-06-26T12:09:52Z

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 <ming.lei@redhat.com>
---
block/bio.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/block/bio.c b/block/bio.c
index a5db117e8dfa..bf7f25889f6e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -870,6 +870,10 @@ 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)
{
--
2.9.4