1 files changed, 35 insertions, 12 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
index ed75bc962fbe..7695dc850785 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -34,6 +34,8 @@
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
 
+#include "internal.h"
+
 void *high_memory;
 struct page *mem_map;
 unsigned long max_mapnr;
@@ -128,20 +130,16 @@ unsigned int kobjsize(const void *objp)
         return PAGE_SIZE << compound_order(page);
 }
 
-/*
- * get a list of pages in an address range belonging to the specified process
- * and indicate the VMA that covers each page
- * - this is potentially dodgy as we may end incrementing the page count of a
- *   slab page or a secondary page from a compound page
- * - don't permit access to VMAs that don't support it, such as I/O mappings
- */
-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 __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)
 {
         struct vm_area_struct *vma;
         unsigned long vm_flags;
         int i;
+        int write = !!(flags & GUP_FLAGS_WRITE);
+        int force = !!(flags & GUP_FLAGS_FORCE);
+        int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
 
         /* calculate required read or write permissions.
          * - if 'force' is set, we only require the "MAY" flags.
@@ -156,7 +154,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 
                 /* protect what we can, including chardevs */
                 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
-                    !(vm_flags & vma->vm_flags))
+                    (!ignore && !(vm_flags & vma->vm_flags)))
                         goto finish_or_fault;
 
                 if (pages) {
@@ -174,6 +172,30 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 finish_or_fault:
         return i ? : -EFAULT;
 }
+
+
+/*
+ * get a list of pages in an address range belonging to the specified process
+ * and indicate the VMA that covers each page
+ * - this is potentially dodgy as we may end incrementing the page count of a
+ *   slab page or a secondary page from a compound page
+ * - don't permit access to VMAs that don't support it, such as I/O mappings
+ */
+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);
 
 DEFINE_RWLOCK(vmlist_lock);
@@ -1432,7 +1454,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
 
         /* Don't let a single process grow too big:
            leave 3% of the size of this process for other processes */
-        allowed -= current->mm->total_vm / 32;
+        if (mm)
+                allowed -= mm->total_vm / 32;
 
         /*
          * cast `allowed' as a signed long because vm_committed_space