mm: move part of wp_page_reuse() into the single call site

wp_page_reuse() handles write shared faults which is needed only in
wp_page_shared().  Move the handling only into that location to make
wp_page_reuse() simpler and avoid a strange situation when we sometimes
pass in locked page, sometimes unlocked etc.

Link: http://lkml.kernel.org/r/1479460644-25076-15-git-send-email-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index ad45289..82e7689 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2102,8 +2102,7 @@ static void fault_dirty_shared_page(struct vm_area_struct *vma,
  * case, all we need to do here is to mark the page as writable and update
  * any related book-keeping.
  */
-static inline int wp_page_reuse(struct vm_fault *vmf,
-                               int page_mkwrite, int dirty_shared)
+static inline void wp_page_reuse(struct vm_fault *vmf)
        __releases(vmf->ptl)
 {
        struct vm_area_struct *vma = vmf->vma;
@@ -2123,16 +2122,6 @@ static inline int wp_page_reuse(struct vm_fault *vmf,
        if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1))
                update_mmu_cache(vma, vmf->address, vmf->pte);
        pte_unmap_unlock(vmf->pte, vmf->ptl);
-
-       if (dirty_shared) {
-               if (!page_mkwrite)
-                       lock_page(page);
-
-               fault_dirty_shared_page(vma, page);
-               put_page(page);
-       }
-
-       return VM_FAULT_WRITE;
 }
 
 /*
@@ -2307,7 +2296,8 @@ static int wp_pfn_shared(struct vm_fault *vmf)
                        return 0;
                }
        }
-       return wp_page_reuse(vmf, 0, 0);
+       wp_page_reuse(vmf);
+       return VM_FAULT_WRITE;
 }
 
 static int wp_page_shared(struct vm_fault *vmf)
@@ -2345,7 +2335,13 @@ static int wp_page_shared(struct vm_fault *vmf)
                page_mkwrite = 1;
        }
 
-       return wp_page_reuse(vmf, page_mkwrite, 1);
+       wp_page_reuse(vmf);
+       if (!page_mkwrite)
+               lock_page(vmf->page);
+       fault_dirty_shared_page(vma, vmf->page);
+       put_page(vmf->page);
+
+       return VM_FAULT_WRITE;
 }
 
 /*
@@ -2420,7 +2416,8 @@ static int do_wp_page(struct vm_fault *vmf)
                                page_move_anon_rmap(vmf->page, vma);
                        }
                        unlock_page(vmf->page);
-                       return wp_page_reuse(vmf, 0, 0);
+                       wp_page_reuse(vmf);
+                       return VM_FAULT_WRITE;
                }
                unlock_page(vmf->page);
        } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==