[-mm][splitlru][PATCH 1/3] introduce __get_user_pages()

[kosaki.motohiro@jp.fujitsu.com]

[-- Attachment #1: __get_user_pages.patch --]
[-- Type: text/plain, Size: 3336 bytes --]

new munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS.
because current get_user_pages() can't grab PROT_NONE pages theresore
it cause PROT_NONE pages can't munlock.



Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Li Zefan <lizf@cn.fujitsu.com>
CC: Hugh Dickins <hugh@veritas.com>
CC: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
CC: Rik van Riel <riel@redhat.com>

---
 mm/internal.h |    8 ++++++++
 mm/memory.c   |   37 +++++++++++++++++++++++++++++++------
 2 files changed, 39 insertions(+), 6 deletions(-)

Index: b/mm/memory.c
===================================================================
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1108,12 +1108,17 @@ static inline int use_zero_page(struct v
 	return !vma->vm_ops || !vma->vm_ops->fault;
 }
 
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-		unsigned long start, int len, int write, int force,
+
+
+int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+		     unsigned long start, int len, int flags,
 		struct page **pages, struct vm_area_struct **vmas)
 {
 	int i;
-	unsigned int vm_flags;
+	unsigned int vm_flags = 0;
+	int write = !!(flags & GUP_FLAGS_WRITE);
+	int force = !!(flags & GUP_FLAGS_FORCE);
+	int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
 
 	if (len <= 0)
 		return 0;
@@ -1137,7 +1142,9 @@ int get_user_pages(struct task_struct *t
 			pud_t *pud;
 			pmd_t *pmd;
 			pte_t *pte;
-			if (write) /* user gate pages are read-only */
+
+			/* user gate pages are read-only */
+			if (!ignore && write)
 				return i ? : -EFAULT;
 			if (pg > TASK_SIZE)
 				pgd = pgd_offset_k(pg);
@@ -1169,8 +1176,9 @@ int get_user_pages(struct task_struct *t
 			continue;
 		}
 
-		if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
-				|| !(vm_flags & vma->vm_flags))
+		if (!vma ||
+		    (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
+		    (!ignore && !(vm_flags & vma->vm_flags)))
 			return i ? : -EFAULT;
 
 		if (is_vm_hugetlb_page(vma)) {
@@ -1245,6 +1253,23 @@ int get_user_pages(struct task_struct *t
 	} while (len);
 	return i;
 }
+
+int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+		unsigned long start, int len, int write, int force,
+		struct page **pages, struct vm_area_struct **vmas)
+{
+	int flags = 0;
+
+	if (write)
+		flags |= GUP_FLAGS_WRITE;
+	if (force)
+		flags |= GUP_FLAGS_FORCE;
+
+	return __get_user_pages(tsk, mm,
+				start, len, flags,
+				pages, vmas);
+}
+
 EXPORT_SYMBOL(get_user_pages);
 
 pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
Index: b/mm/internal.h
===================================================================
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -243,4 +243,12 @@ static inline void mminit_validate_memmo
 }
 #endif /* CONFIG_SPARSEMEM */
 
+#define GUP_FLAGS_WRITE                  0x1
+#define GUP_FLAGS_FORCE                  0x2
+#define GUP_FLAGS_IGNORE_VMA_PERMISSIONS 0x4
+
+int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+		     unsigned long start, int len, int flags,
+		     struct page **pages, struct vm_area_struct **vmas);
+
 #endif

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