summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--include/linux/mmu_notifier.h10
-rw-r--r--mm/mmu_notifier.c23
2 files changed, 28 insertions, 5 deletions
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index b8200782dede..1a6a9eb6d3fa 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -169,11 +169,11 @@ struct mmu_notifier_ops {
* the last refcount is dropped.
*
* If blockable argument is set to false then the callback cannot
- * sleep and has to return with -EAGAIN. 0 should be returned
- * otherwise. Please note that if invalidate_range_start approves
- * a non-blocking behavior then the same applies to
- * invalidate_range_end.
- *
+ * sleep and has to return with -EAGAIN if sleeping would be required.
+ * 0 should be returned otherwise. Please note that notifiers that can
+ * fail invalidate_range_start are not allowed to implement
+ * invalidate_range_end, as there is no mechanism for informing the
+ * notifier that its start failed.
*/
int (*invalidate_range_start)(struct mmu_notifier *subscription,
const struct mmu_notifier_range *range);
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 61ee40ed804e..459d195d2ff6 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -501,10 +501,33 @@ static int mn_hlist_invalidate_range_start(
"");
WARN_ON(mmu_notifier_range_blockable(range) ||
_ret != -EAGAIN);
+ /*
+ * We call all the notifiers on any EAGAIN,
+ * there is no way for a notifier to know if
+ * its start method failed, thus a start that
+ * does EAGAIN can't also do end.
+ */
+ WARN_ON(ops->invalidate_range_end);
ret = _ret;
}
}
}
+
+ if (ret) {
+ /*
+ * Must be non-blocking to get here. If there are multiple
+ * notifiers and one or more failed start, any that succeeded
+ * start are expecting their end to be called. Do so now.
+ */
+ hlist_for_each_entry_rcu(subscription, &subscriptions->list,
+ hlist, srcu_read_lock_held(&srcu)) {
+ if (!subscription->ops->invalidate_range_end)
+ continue;
+
+ subscription->ops->invalidate_range_end(subscription,
+ range);
+ }
+ }
srcu_read_unlock(&srcu, id);
return ret;