mm: gup: use get_user_pages_unlocked

This allows those get_user_pages calls to pass FAULT_FLAG_ALLOW_RETRY to
the page fault in order to release the mmap_sem during the I/O.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Peter Feiner <pfeiner@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 5 deletions

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 5077afcd9e11..b1597690530c 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -99,11 +99,8 @@ static int process_vm_rw_single_vec(unsigned long addr,
                 size_t bytes;
 
                 /* Get the pages we're interested in */
-                down_read(&mm->mmap_sem);
-                pages = get_user_pages(task, mm, pa, pages,
-                                      vm_write, 0, process_pages, NULL);
-                up_read(&mm->mmap_sem);
-
+                pages = get_user_pages_unlocked(task, mm, pa, pages,
+                                                vm_write, 0, process_pages);
                 if (pages <= 0)
                         return -EFAULT;