[PATCH] Drop page table lock before calling migrate_page_add().

migrate_page_add cannot be called with a spinlock held (calls isolate_lru_page
which calles schedule_on_each_cpu). Drop ptl lock in check_pte_range before
calling migrate_page_add().

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.15-rc5-mm2/mm/mempolicy.c
===================================================================
--- linux-2.6.15-rc5-mm2.orig/mm/mempolicy.c	2005-12-12 09:10:34.000000000 -0800
+++ linux-2.6.15-rc5-mm2/mm/mempolicy.c	2005-12-12 15:17:57.000000000 -0800
@@ -210,8 +210,11 @@ static int check_pte_range(struct vm_are
 
 		if (flags & MPOL_MF_STATS)
 			gather_stats(page, private);
-		else if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+		else if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
+			spin_unlock(ptl);
 			migrate_page_add(vma, page, private, flags);
+			spin_lock(ptl);
+		}
 		else
 			break;
 	} while (pte++, addr += PAGE_SIZE, addr != end);