--- v6
+++ v2
@@ -1,71 +1,69 @@
-migrate_misplaced_page() is only called during the page fault handling so
-it's better to pass the pointer to the struct vm_fault instead of the vma.
+The current maybe_mkwrite() is getting passed the pointer to the vma
+structure to fetch the vm_flags field.
 
-This way during the speculative page fault path the saved vma->vm_flags
-could be used.
+When dealing with the speculative page fault handler, it will be better to
+rely on the cached vm_flags value stored in the vm_fault structure.
+
+This patch introduce a __maybe_mkwrite() service which can be called by
+passing the value of the vm_flags field.
+
+There is no change functional changes expected for the other callers of
+maybe_mkwrite().
 
 Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
 ---
- include/linux/migrate.h | 4 ++--
- mm/memory.c             | 2 +-
- mm/migrate.c            | 4 ++--
- 3 files changed, 5 insertions(+), 5 deletions(-)
+ include/linux/mm.h | 9 +++++++--
+ mm/memory.c        | 6 +++---
+ 2 files changed, 10 insertions(+), 5 deletions(-)
 
-diff --git a/include/linux/migrate.h b/include/linux/migrate.h
-index 0c6fe904bc97..08960ec74246 100644
---- a/include/linux/migrate.h
-+++ b/include/linux/migrate.h
-@@ -126,14 +126,14 @@ static inline void __ClearPageMovable(struct page *page)
- #ifdef CONFIG_NUMA_BALANCING
- extern bool pmd_trans_migrating(pmd_t pmd);
- extern int migrate_misplaced_page(struct page *page,
--				  struct vm_area_struct *vma, int node);
-+				  struct vm_fault *vmf, int node);
- #else
- static inline bool pmd_trans_migrating(pmd_t pmd)
+diff --git a/include/linux/mm.h b/include/linux/mm.h
+index 43d313ff3a5b..0f4ddd72b172 100644
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -668,13 +668,18 @@ void free_compound_page(struct page *page);
+  * pte_mkwrite.  But get_user_pages can cause write faults for mappings
+  * that do not have writing enabled, when used by access_process_vm.
+  */
+-static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
++static inline pte_t __maybe_mkwrite(pte_t pte, unsigned long vma_flags)
  {
- 	return false;
+-	if (likely(vma->vm_flags & VM_WRITE))
++	if (likely(vma_flags & VM_WRITE))
+ 		pte = pte_mkwrite(pte);
+ 	return pte;
  }
- static inline int migrate_misplaced_page(struct page *page,
--					 struct vm_area_struct *vma, int node)
-+					 struct vm_fault *vmf, int node)
- {
- 	return -EAGAIN; /* can't migrate now */
- }
+ 
++static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
++{
++	return __maybe_mkwrite(pte, vma->vm_flags);
++}
++
+ int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
+ 		struct page *page);
+ int finish_fault(struct vm_fault *vmf);
 diff --git a/mm/memory.c b/mm/memory.c
-index 79dfd2a60224..e4c0f08b78e8 100644
+index c6b18cc87e90..ad7b6372d302 100644
 --- a/mm/memory.c
 +++ b/mm/memory.c
-@@ -3878,7 +3878,7 @@ static int do_numa_page(struct vm_fault *vmf)
- 	}
+@@ -2269,7 +2269,7 @@ static inline void wp_page_reuse(struct vm_fault *vmf)
  
- 	/* Migrate to the requested node */
--	migrated = migrate_misplaced_page(page, vma, target_nid);
-+	migrated = migrate_misplaced_page(page, vmf, target_nid);
- 	if (migrated) {
- 		page_nid = target_nid;
- 		flags |= TNF_MIGRATED;
-diff --git a/mm/migrate.c b/mm/migrate.c
-index 33224b92db98..6e1ae62501da 100644
---- a/mm/migrate.c
-+++ b/mm/migrate.c
-@@ -1900,7 +1900,7 @@ bool pmd_trans_migrating(pmd_t pmd)
-  * node. Caller is expected to have an elevated reference count on
-  * the page that will be dropped by this function before returning.
-  */
--int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
-+int migrate_misplaced_page(struct page *page, struct vm_fault *vmf,
- 			   int node)
- {
- 	pg_data_t *pgdat = NODE_DATA(node);
-@@ -1913,7 +1913,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
- 	 * with execute permissions as they are probably shared libraries.
- 	 */
- 	if (page_mapcount(page) != 1 && page_is_file_cache(page) &&
--	    (vma->vm_flags & VM_EXEC))
-+	    (vmf->vma_flags & VM_EXEC))
- 		goto out;
- 
- 	/*
+ 	flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
+ 	entry = pte_mkyoung(vmf->orig_pte);
+-	entry = maybe_mkwrite(pte_mkdirty(entry), vma);
++	entry = __maybe_mkwrite(pte_mkdirty(entry), vmf->vma_flags);
+ 	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);
+@@ -2359,8 +2359,8 @@ static int wp_page_copy(struct vm_fault *vmf)
+ 			inc_mm_counter_fast(mm, MM_ANONPAGES);
+ 		}
+ 		flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
+-		entry = mk_pte(new_page, vma->vm_page_prot);
+-		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
++		entry = mk_pte(new_page, vmf->vma_page_prot);
++		entry = __maybe_mkwrite(pte_mkdirty(entry), vmf->vma_flags);
+ 		/*
+ 		 * Clear the pte entry and flush it first, before updating the
+ 		 * pte with the new entry. This will avoid a race condition
 -- 
 2.7.4