[PATCH v2 09/18] io_uring/memmap: add IO_REGION_F_SINGLE_REF

[Pavel Begunkov <asml.silence@gmail.com>]

Kernel allocated compound pages will have just one reference for the
entire page array, add a flag telling io_free_region about that.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/memmap.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/io_uring/memmap.c b/io_uring/memmap.c
index 15fefbed77ec..cdd620bdd3ee 100644
--- a/io_uring/memmap.c
+++ b/io_uring/memmap.c
@@ -198,15 +198,22 @@ void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
 enum {
 	IO_REGION_F_VMAP			= 1,
 	IO_REGION_F_USER_PINNED			= 2,
+	IO_REGION_F_SINGLE_REF			= 4,
 };
 
 void io_free_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr)
 {
 	if (mr->pages) {
+		long nr_pages = mr->nr_pages;
+
+		if (mr->flags & IO_REGION_F_SINGLE_REF)
+			nr_pages = 1;
+
 		if (mr->flags & IO_REGION_F_USER_PINNED)
-			unpin_user_pages(mr->pages, mr->nr_pages);
+			unpin_user_pages(mr->pages, nr_pages);
 		else
-			release_pages(mr->pages, mr->nr_pages);
+			release_pages(mr->pages, nr_pages);
+
 		kvfree(mr->pages);
 	}
 	if ((mr->flags & IO_REGION_F_VMAP) && mr->ptr)
-- 
2.46.0