fs/buffer.c: remove redundant initialization in alloc_page_buffers()

buffer_head comes from kmem_cache_zalloc(), no need to zero its fields.
Signed-off-by: NYan Hong <clouds.yan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/buffer.c

@@ -849,13 +849,10 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
 		if (!bh)
 			goto no_grow;
 
-		bh->b_bdev = NULL;
 		bh->b_this_page = head;
 		bh->b_blocknr = -1;
 		head = bh;
 
-		bh->b_state = 0;
-		atomic_set(&bh->b_count, 0);
 		bh->b_size = size;
 
 		/* Link the buffer to its page */