/*
* Work around locking order reversal in fault / nopfn
* between mmap_sem and bo_reserve: Perform a trylock operation
- * for reserve, and if it fails, retry the fault after scheduling.
+ * for reserve, and if it fails, retry the fault after waiting
+ * for the buffer to become unreserved.
*/
-
- ret = ttm_bo_reserve(bo, true, true, false, 0);
+ ret = ttm_bo_reserve(bo, true, true, false, NULL);
if (unlikely(ret != 0)) {
- if (ret == -EBUSY)
- set_need_resched();
+ if (ret != -EBUSY)
+ return VM_FAULT_NOPAGE;
+
+ if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
+ up_read(&vma->vm_mm->mmap_sem);
+ (void) ttm_bo_wait_unreserved(bo);
+ }
+
+ return VM_FAULT_RETRY;
+ }
+
+ /*
+ * If we'd want to change locking order to
+ * mmap_sem -> bo::reserve, we'd use a blocking reserve here
+ * instead of retrying the fault...
+ */
return VM_FAULT_NOPAGE;
}
case 0:
break;
case -EBUSY:
- set_need_resched();
case -ERESTARTSYS:
retval = VM_FAULT_NOPAGE;
goto out_unlock;