BIO_PAGE_PINNED to indicate that the pages in a bio were pinned (FOLL_PIN)
and that the pin will need removing.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Jan Kara <jack@suse.cz>
cc: Christoph Hellwig <hch@lst.de>
cc: Matthew Wilcox <willy@infradead.org>
cc: Logan Gunthorpe <logang@deltatee.com>
cc: linux-block@vger.kernel.org
---
 include/linux/blk_types.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 86711fb0534a..42b40156c517 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -319,6 +319,7 @@ struct bio {
  */
 enum {
 	BIO_PAGE_REFFED,	/* Pages need refs putting (equivalent to FOLL_GET) */
+	BIO_PAGE_PINNED,	/* Pages need unpinning (equivalent to FOLL_PIN) */
 	BIO_CLONED,		/* doesn't own data */
 	BIO_BOUNCED,		/* bio is a bounce bio */
 	BIO_QUIET,		/* Make BIO Quiet */

On Fri, Jan 20, 2023 at 05:55:53PM +0000, David Howells wrote:
> BIO_PAGE_PINNED to indicate that the pages in a bio were pinned (FOLL_PIN)
> and that the pin will need removing.

Just adding the flag without the infrastructure and users is a bit
silly.  See the link to my branch to see what I think is better split.