[PATCH] add check do_direct_IO() return val

[Joe Jin <joe.jin@oracle.com>]

This is the patch for check do_direct_IO() return val.

At do_direct_IO(), sometimes dio_get_page() will return -EFAULT/-ENOMEM,
according to orig source, it will go on left work. buf for dio_get_page()
return a error will made many useful member of dio not initialized like
dio->map_bh and others, at this point, kernel will panic.

Signed-off-by: Joe Jin <joe.jin@oracle.com>


---
--- linux-2.6.22/fs/direct-io.c.orig	2007-07-26 11:32:27.000000000 +0800
+++ linux-2.6.22/fs/direct-io.c	2007-07-26 11:33:58.000000000 +0800
@@ -1031,7 +1031,9 @@ direct_io_worker(int rw, struct kiocb *i
 			((dio->final_block_in_request - dio->block_in_file) <<
 					blkbits);
 
-		if (ret) {
+		if (ret == -EFAULT || ret == -ENOMEM) 
+			goto out;
+		else if (ret) {
 			dio_cleanup(dio);
 			break;
 		}
@@ -1113,6 +1115,7 @@ direct_io_worker(int rw, struct kiocb *i
 	} else
 		BUG_ON(ret != -EIOCBQUEUED);
 
+out:
 	return ret;
 }