1 files changed, 14 insertions, 8 deletions

diff --git a/mm/fremap.c b/mm/fremap.c
index a0aaf0e56800..2db886e31044 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -160,15 +160,11 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
         /*
          * Make sure the vma is shared, that it supports prefaulting,
          * and that the remapped range is valid and fully within
-         * the single existing vma.  vm_private_data is used as a
-         * swapout cursor in a VM_NONLINEAR vma.
+         * the single existing vma.
          */
         if (!vma || !(vma->vm_flags & VM_SHARED))
                 goto out;
 
-        if (vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR))
-                goto out;
-
         if (!vma->vm_ops || !vma->vm_ops->remap_pages)
                 goto out;
 
@@ -177,6 +173,13 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 
         /* Must set VM_NONLINEAR before any pages are populated. */
         if (!(vma->vm_flags & VM_NONLINEAR)) {
+                /*
+                 * vm_private_data is used as a swapout cursor
+                 * in a VM_NONLINEAR vma.
+                 */
+                if (vma->vm_private_data)
+                        goto out;
+
                 /* Don't need a nonlinear mapping, exit success */
                 if (pgoff == linear_page_index(vma, start)) {
                         err = 0;
@@ -184,6 +187,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
                 }
 
                 if (!has_write_lock) {
+get_write_lock:
                         up_read(&mm->mmap_sem);
                         down_write(&mm->mmap_sem);
                         has_write_lock = 1;
@@ -199,7 +203,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
                         unsigned long addr;
                         struct file *file = get_file(vma->vm_file);
 
-                        flags &= MAP_NONBLOCK;
+                        flags = (flags & MAP_NONBLOCK) | MAP_POPULATE;
                         addr = mmap_region(file, start, size,
                                         flags, vma->vm_flags, pgoff);
                         fput(file);
@@ -225,6 +229,8 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
                  * drop PG_Mlocked flag for over-mapped range
                  */
                 vm_flags_t saved_flags = vma->vm_flags;
+                if (!has_write_lock)
+                        goto get_write_lock;
                 munlock_vma_pages_range(vma, start, start + size);
                 vma->vm_flags = saved_flags;
         }
@@ -232,13 +238,13 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
         mmu_notifier_invalidate_range_start(mm, start, start + size);
         err = vma->vm_ops->remap_pages(vma, start, size, pgoff);
         mmu_notifier_invalidate_range_end(mm, start, start + size);
-        if (!err && !(flags & MAP_NONBLOCK)) {
+        if (!err) {
                 if (vma->vm_flags & VM_LOCKED) {
                         /*
                          * might be mapping previously unmapped range of file
                          */
                         mlock_vma_pages_range(vma, start, start + size);
-                } else {
+                } else if (!(flags & MAP_NONBLOCK)) {
                         if (unlikely(has_write_lock)) {
                                 downgrade_write(&mm->mmap_sem);
                                 has_write_lock = 0;