[PATCH v3 3/3] xen/privcmd: Convert get_user_pages*() to pin_user_pages*()

[Souptick Joarder <jrdr.linux@xxxxxxxxx>]

In 2019, we introduced pin_user_pages*() and now we are converting
get_user_pages*() to the new API as appropriate. [1] & [2] could
be referred for more information. This is case 5 as per document [1].

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
        https://lwn.net/Articles/807108/

Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Paul Durrant <xadimgnik@xxxxxxxxx>
---
 drivers/xen/privcmd.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 079d35b..63abe6c 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -593,7 +593,7 @@ static int lock_pages(
                if (requested > nr_pages)
                        return -ENOSPC;
 
-               page_count = get_user_pages_fast(
+               page_count = pin_user_pages_fast(
                        (unsigned long) kbufs[i].uptr,
                        requested, FOLL_WRITE, pages);
                if (page_count < 0)
@@ -609,13 +609,7 @@ static int lock_pages(
 
 static void unlock_pages(struct page *pages[], unsigned int nr_pages)
 {
-       unsigned int i;
-
-       for (i = 0; i < nr_pages; i++) {
-               if (!PageDirty(pages[i]))
-                       set_page_dirty_lock(pages[i]);
-               put_page(pages[i]);
-       }
+       unpin_user_pages_dirty_lock(pages, nr_pages, true);
 }
 
 static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
-- 
1.9.1