1 files changed, 25 insertions, 9 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index 6ea204cc751e..01f9793591f6 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -937,9 +937,10 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
         /* mlock MCL_FUTURE? */
         if (vm_flags & VM_LOCKED) {
                 unsigned long locked, lock_limit;
-                locked = mm->locked_vm << PAGE_SHIFT;
+                locked = len >> PAGE_SHIFT;
+                locked += mm->locked_vm;
                 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
-                locked += len;
+                lock_limit >>= PAGE_SHIFT;
                 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
                         return -EAGAIN;
         }
@@ -1009,8 +1010,7 @@ munmap_back:
         }
 
         /* Check against address space limit. */
-        if ((mm->total_vm << PAGE_SHIFT) + len
-            > current->signal->rlim[RLIMIT_AS].rlim_cur)
+        if (!may_expand_vm(mm, len >> PAGE_SHIFT))
                 return -ENOMEM;
 
         if (accountable && (!(flags & MAP_NORESERVE) ||
@@ -1421,7 +1421,7 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un
         struct rlimit *rlim = current->signal->rlim;
 
         /* address space limit tests */
-        if (mm->total_vm + grow > rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT)
+        if (!may_expand_vm(mm, grow))
                 return -ENOMEM;
 
         /* Stack limit test */
@@ -1823,9 +1823,10 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
          */
         if (mm->def_flags & VM_LOCKED) {
                 unsigned long locked, lock_limit;
-                locked = mm->locked_vm << PAGE_SHIFT;
+                locked = len >> PAGE_SHIFT;
+                locked += mm->locked_vm;
                 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
-                locked += len;
+                lock_limit >>= PAGE_SHIFT;
                 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
                         return -EAGAIN;
         }
@@ -1848,8 +1849,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
         }
 
         /* Check against address space limits *after* clearing old maps... */
-        if ((mm->total_vm << PAGE_SHIFT) + len
-            > current->signal->rlim[RLIMIT_AS].rlim_cur)
+        if (!may_expand_vm(mm, len >> PAGE_SHIFT))
                 return -ENOMEM;
 
         if (mm->map_count > sysctl_max_map_count)
@@ -2019,3 +2019,19 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
         }
         return new_vma;
 }
+
+/*
+ * Return true if the calling process may expand its vm space by the passed
+ * number of pages
+ */
+int may_expand_vm(struct mm_struct *mm, unsigned long npages)
+{
+        unsigned long cur = mm->total_vm;       /* pages */
+        unsigned long lim;
+
+        lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
+
+        if (cur + npages > lim)
+                return 0;
+        return 1;
+}