memcg: take reference before releasing rcu_read_lock

[firefly-linux-kernel-4.4.55.git] / mm / fremap.c

diff --git a/mm/fremap.c b/mm/fremap.c
index 0cd4c11488edf8c8fd33346e9b94e28fb3272aa1..87da3590c61e20287b4854e8212c178f96cb73c6 100644 (file)
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -129,7 +129,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
        struct vm_area_struct *vma;
        int err = -EINVAL;
        int has_write_lock = 0;
-       vm_flags_t vm_flags;
+       vm_flags_t vm_flags = 0;
 
        if (prot)
                return err;
@@ -204,10 +204,8 @@ get_write_lock:
                        unsigned long addr;
                        struct file *file = get_file(vma->vm_file);
 
-                       vm_flags = vma->vm_flags;
-                       if (!(flags & MAP_NONBLOCK))
-                               vm_flags |= VM_POPULATE;
-                       addr = mmap_region(file, start, size, vm_flags, pgoff);
+                       addr = mmap_region(file, start, size,
+                                       vma->vm_flags, pgoff);
                        fput(file);
                        if (IS_ERR_VALUE(addr)) {
                                err = addr;
@@ -226,12 +224,6 @@ get_write_lock:
                mutex_unlock(&mapping->i_mmap_mutex);
        }
 
-       if (!(flags & MAP_NONBLOCK) && !(vma->vm_flags & VM_POPULATE)) {
-               if (!has_write_lock)
-                       goto get_write_lock;
-               vma->vm_flags |= VM_POPULATE;
-       }
-
        if (vma->vm_flags & VM_LOCKED) {
                /*
                 * drop PG_Mlocked flag for over-mapped range
@@ -254,7 +246,8 @@ get_write_lock:
         */
 
 out:
-       vm_flags = vma->vm_flags;
+       if (vma)
+               vm_flags = vma->vm_flags;
        if (likely(!has_write_lock))
                up_read(&mm->mmap_sem);
        else