- We cannot hold i_shared_lock across momve_one_page() because
move_one_page() needs to perform __GFP_WAIT allocations of pagetable pages.
- Move the cond_resched() out so we test it once per page rather than only
when move_one_page() returns -EAGAIN.
---
25-akpm/mm/mremap.c | 21 +--------------------
1 files changed, 1 insertion(+), 20 deletions(-)
diff -puN mm/mremap.c~i_shared_lock-mremap-fix mm/mremap.c
--- 25/mm/mremap.c~i_shared_lock-mremap-fix Wed Apr 21 15:23:57 2004
+++ 25-akpm/mm/mremap.c Wed Apr 21 15:24:40 2004
@@ -143,22 +143,10 @@ static int move_page_tables(struct vm_ar
unsigned long new_addr, unsigned long old_addr,
unsigned long len, int *cows)
{
- struct address_space *mapping = NULL;
unsigned long offset;
flush_cache_range(vma, old_addr, old_addr + len);
- if (vma->vm_file) {
- /*
- * Subtle point from Rajesh Venkatasubramanian: before
- * moving file-based ptes, we must lock vmtruncate out,
- * since it might clean the dst vma before the src vma,
- * and we propagate stale pages into the dst afterward.
- */
- mapping = vma->vm_file->f_mapping;
- spin_lock(&mapping->i_shared_lock);
- }
-
/*
* This is not the clever way to do this, but we're taking the
* easy way out on the assumption that most remappings will be
@@ -175,21 +163,14 @@ static int move_page_tables(struct vm_ar
* brought back in (if it's still shared by then).
*/
if (ret == -EAGAIN) {
- if (mapping)
- spin_unlock(&mapping->i_shared_lock);
- cond_resched();
ret = make_page_exclusive(vma, old_addr+offset);
- if (mapping)
- spin_lock(&mapping->i_shared_lock);
offset -= PAGE_SIZE;
(*cows)++;
}
if (ret)
break;
+ cond_resched();
}
-
- if (mapping)
- spin_unlock(&mapping->i_shared_lock);
return offset;
}
_