diff options
Diffstat (limited to 'sys/vm/vm_map.c')
| -rw-r--r-- | sys/vm/vm_map.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c index b173fdd..13b9050 100644 --- a/sys/vm/vm_map.c +++ b/sys/vm/vm_map.c @@ -1350,6 +1350,16 @@ vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry) entry->offset = prev->offset; if (entry->prev != &map->header) vm_map_entry_resize_free(map, entry->prev); + + /* + * If the backing object is the vnode object, + * vm_object_deallocate() results in a call to + * vrele(). Because the reference to the + * object is not last, vrele() does not lock + * the vnode, and map lock can be kept without + * causing vnode lock to be taken after the + * map lock. + */ if (prev->object.vm_object) vm_object_deallocate(prev->object.vm_object); vm_map_entry_dispose(map, prev); @@ -1371,6 +1381,10 @@ vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry) vm_map_entry_unlink(map, next); entry->end = next->end; vm_map_entry_resize_free(map, entry); + + /* + * See comment above. + */ if (next->object.vm_object) vm_object_deallocate(next->object.vm_object); vm_map_entry_dispose(map, next); @@ -2729,6 +2743,12 @@ vmspace_fork(struct vmspace *vm1) /* Transfer the second reference too. */ vm_object_reference( old_entry->object.vm_object); + + /* + * As in vm_map_simplify_entry(), the + * vnode lock may not be acquired in + * this call to vm_object_deallocate(). + */ vm_object_deallocate(object); object = old_entry->object.vm_object; } |
