[PATCH v3 14/23] fs/io_uring: set FOLL_PIN via pin_user_pages()

John Hubbard
2019-11-12T00:09:02Z

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_longterm_pages().

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
fs/io_uring.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f9a38998f2fc..0f307f2c7cac 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3433,9 +3433,8 @@ 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,
- FOLL_WRITE | FOLL_LONGTERM,
- pages, vmas);
+ pret = pin_longterm_pages(ubuf, nr_pages, FOLL_WRITE, pages,
+ vmas);
if (pret == nr_pages) {
/* don't support file backed memory */
for (j = 0; j < nr_pages; j++) {
--
2.24.0