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- Add further vm object locking to vm_object_deallocate(), specifically,

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for accessing a vm object's shadows.
This commit is contained in:
Alan Cox 2003-06-04 21:07:42 +00:00
parent fee5c3f1f8
commit b72b0115ee
1 changed files with 12 additions and 2 deletions
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14
sys/vm/vm_object.c
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@ -476,6 +476,14 @@ vm_object_deallocate(vm_object_t object)
("vm_object_deallocate: ref_count: %d, shadow_count: %d",
object->ref_count,
object->shadow_count));
if (!VM_OBJECT_TRYLOCK(robject)) {
/*
* Avoid a potential deadlock.
*/
object->ref_count++;
VM_OBJECT_UNLOCK(object);
continue;
}
if ((robject->handle == NULL) &&
(robject->type == OBJT_DEFAULT ||
robject->type == OBJT_SWAP)) {
@ -487,22 +495,24 @@ vm_object_deallocate(vm_object_t object)
object->paging_in_progress
) {
/* XXX */ VM_OBJECT_UNLOCK(object);
/* XXX */ VM_OBJECT_UNLOCK(robject);
vm_object_pip_sleep(robject, "objde1");
vm_object_pip_sleep(object, "objde2");
/* XXX */ VM_OBJECT_LOCK(robject);
/* XXX */ VM_OBJECT_LOCK(object);
}
VM_OBJECT_UNLOCK(object);
if (robject->ref_count == 1) {
/* XXX */ VM_OBJECT_LOCK(robject);
robject->ref_count--;
object = robject;
goto doterm;
}
object = robject;
/* XXX */ VM_OBJECT_UNLOCK(object);
vm_object_collapse(object);
continue;
}
VM_OBJECT_UNLOCK(robject);
}
VM_OBJECT_UNLOCK(object);
goto done;