[v12,16/22] fs/io_uring: set FOLL_PIN via pin_user_pages()

Commit Message

John Hubbard Jan. 7, 2020, 10:45 p.m. UTC

Convert fs/io_uring to use the new pin_user_pages() call, which sets
FOLL_PIN. Setting FOLL_PIN is now required for code that requires
tracking of pinned pages, and therefore for any code that calls
put_user_page().

In partial anticipation of this work, the io_uring code was already
calling put_user_page() instead of put_page(). Therefore, in order to
convert from the get_user_pages()/put_page() model, to the
pin_user_pages()/put_user_page() model, the only change required
here is to change get_user_pages() to pin_user_pages().

Reviewed-by: Jens Axboe <[e-mail]>
Reviewed-by: Jan Kara <[e-mail]>
Signed-off-by: John Hubbard <[e-mail]>
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 562e3a1a1bf9..9f804cb25c61 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4815,7 +4815,7 @@  static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
 
 		ret = 0;
 		down_read(&current->mm->mmap_sem);
-		pret = get_user_pages(ubuf, nr_pages,
+		pret = pin_user_pages(ubuf, nr_pages,
 				      FOLL_WRITE | FOLL_LONGTERM,
 				      pages, vmas);
 		if (pret == nr_pages) {