[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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 44b9d69900bc..4c0510e9e7f6 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -259,8 +259,11 @@ static int check_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 
                 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);