From: Hirokazu Takahashi <taka@valinux.co.jp>

Hi Dave,

The following patch checks whether mapping->a_ops exits before
checking mapping->a_ops->migrate_page .

Please apply it after P13.3-Add_comment_why_writeback_isnt_needed.patch .

Thanks,
Hirokazu Takahashi.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
---

 memhotplug-dave/mm/mmigrate.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff -puN mm/mmigrate.c~AA-PM-13.5-check-a_ops-again mm/mmigrate.c
--- memhotplug/mm/mmigrate.c~AA-PM-13.5-check-a_ops-again	2005-07-28 13:50:46.000000000 -0700
+++ memhotplug-dave/mm/mmigrate.c	2005-07-28 13:50:46.000000000 -0700
@@ -378,7 +378,7 @@ migrate_onepage(struct page *page)
 		return ERR_PTR(-ENOMEM);
 	}
 
-	if (mapping->a_ops->migrate_page)
+	if (mapping->a_ops && mapping->a_ops->migrate_page)
 		ret = mapping->a_ops->migrate_page(page, newpage);
 	else
 		ret = generic_migrate_page(page, newpage, migrate_page_common);
_