cleanup: vfs: small comment fix for block_invalidatepage

The patch is aganist 3.1-rc3.
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

fs/buffer.c

@@ -1470,13 +1470,13 @@ static void discard_buffer(struct buffer_head * bh)
 }
 
 /**
- * block_invalidatepage - invalidate part of all of a buffer-backed page
+ * block_invalidatepage - invalidate part or all of a buffer-backed page
  *
  * @page: the page which is affected
  * @offset: the index of the truncation point
  *
  * block_invalidatepage() is called when all or part of the page has become
- * invalidatedby a truncate operation.
+ * invalidated by a truncate operation.
  *
  * block_invalidatepage() does not have to release all buffers, but it must
  * ensure that no dirty buffer is left outside @offset and that no I/O