From: Junxiao Bi <junxiao.bi@oracle.com>
Git-commit: 2dfd06036ba7ae8e7be2daf5a2fff1dac42390bf
Date:   Wed Jun 27 17:09:54 2012 +0800
Subject: aio: make kiocb->private NUll in init_sync_kiocb()
References: bnc#794231
Patch-mainline: Yes, v3.5-rc6
    
    Ocfs2 uses kiocb.*private as a flag of unsigned long size. In
    commit a11f7e6 ocfs2: serialize unaligned aio, the unaligned
    io flag is involved in it to serialize the unaligned aio. As
    *private is not initialized in init_sync_kiocb() of do_sync_write(),
    this unaligned io flag may be unexpectly set in an aligned dio.
    And this will cause OCFS2_I(inode)->ip_unaligned_aio decreased
    to -1 in ocfs2_dio_end_io(), thus the following unaligned dio
    will hang forever at ocfs2_aiodio_wait() in ocfs2_file_aio_write().
    
    Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
    Cc: stable@vger.kernel.org
    Acked-by: Jeff Moyer <jmoyer@redhat.com>
    Signed-off-by: Joel Becker <jlbec@evilplan.org>
Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>

diff --git a/include/linux/aio.h b/include/linux/aio.h
index 2314ad8..b1a520e 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -140,6 +140,7 @@ struct kiocb {
 		(x)->ki_dtor = NULL;			\
 		(x)->ki_obj.tsk = tsk;			\
 		(x)->ki_user_data = 0;                  \
+		(x)->private = NULL;			\
 	} while (0)
 
 #define AIO_RING_MAGIC			0xa10a10a1
