[Xen-devel] [PATCH v2 29/34] mm/process_vm_access.c: convert put_page() to put_user_page*()

[john.hubbard@xxxxxxxxx]

From: John Hubbard <jhubbard@xxxxxxxxxx>

For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page() or
release_pages().

This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").

Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Christopher Yeoh <cyeoh@xxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jann Horn <jann@xxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Rashika Kheria <rashika.kheria@xxxxxxxxx>
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
 mm/process_vm_access.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 357aa7bef6c0..4d29d54ec93f 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -96,7 +96,7 @@ static int process_vm_rw_single_vec(unsigned long addr,
                flags |= FOLL_WRITE;
 
        while (!rc && nr_pages && iov_iter_count(iter)) {
-               int pages = min(nr_pages, max_pages_per_loop);
+               int pinned_pages = min(nr_pages, max_pages_per_loop);
                int locked = 1;
                size_t bytes;
 
@@ -106,14 +106,15 @@ static int process_vm_rw_single_vec(unsigned long addr,
                 * current/current->mm
                 */
                down_read(&mm->mmap_sem);
-               pages = get_user_pages_remote(task, mm, pa, pages, flags,
-                                             process_pages, NULL, &locked);
+               pinned_pages = get_user_pages_remote(task, mm, pa, pinned_pages,
+                                                    flags, process_pages, NULL,
+                                                    &locked);
                if (locked)
                        up_read(&mm->mmap_sem);
-               if (pages <= 0)
+               if (pinned_pages <= 0)
                        return -EFAULT;
 
-               bytes = pages * PAGE_SIZE - start_offset;
+               bytes = pinned_pages * PAGE_SIZE - start_offset;
                if (bytes > len)
                        bytes = len;
 
@@ -122,10 +123,9 @@ static int process_vm_rw_single_vec(unsigned long addr,
                                         vm_write);
                len -= bytes;
                start_offset = 0;
-               nr_pages -= pages;
-               pa += pages * PAGE_SIZE;
-               while (pages)
-                       put_page(process_pages[--pages]);
+               nr_pages -= pinned_pages;
+               pa += pinned_pages * PAGE_SIZE;
+               put_user_pages(process_pages, pinned_pages);
        }
 
        return rc;
-- 
2.22.0


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