userfaultfd: non-cooperative: optimize mremap_userfaultfd_complete()

Optimize the mremap_userfaultfd_complete() interface to pass only the
vm_userfaultfd_ctx pointer through the stack as a microoptimization.

Link: http://lkml.kernel.org/r/20161216144821.5183-13-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 68f978beefac..5d37c37854b0 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -608,11 +608,11 @@ void mremap_userfaultfd_prep(struct vm_area_struct *vma,
         }
 }
 
-void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx vm_ctx,
+void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
                                  unsigned long from, unsigned long to,
                                  unsigned long len)
 {
-        struct userfaultfd_ctx *ctx = vm_ctx.ctx;
+        struct userfaultfd_ctx *ctx = vm_ctx->ctx;
         struct userfaultfd_wait_queue ewq;
 
         if (!ctx)