VM: add "vm_munmap()" helper function

Like the vm_brk() function, this is the same as "do_munmap()", except it
does the VM locking for the caller.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i810/i810_dma.c b/drivers/gpu/drm/i810/i810_dma.c
index 2c8a60c3b98e..b85337f06fbf 100644
--- a/drivers/gpu/drm/i810/i810_dma.c
+++ b/drivers/gpu/drm/i810/i810_dma.c
@@ -157,11 +157,9 @@ static int i810_unmap_buffer(struct drm_buf *buf)
         if (buf_priv->currently_mapped != I810_BUF_MAPPED)
                 return -EINVAL;
 
-        down_write(&current->mm->mmap_sem);
-        retcode = do_munmap(current->mm,
+        retcode = vm_munmap(current->mm,
                             (unsigned long)buf_priv->virtual,
                             (size_t) buf->total);
-        up_write(&current->mm->mmap_sem);
 
         buf_priv->currently_mapped = I810_BUF_UNMAPPED;
         buf_priv->virtual = NULL;