From: Hou Tao <houtao1@xxxxxxxxxx>
Local storage map is accessible for both sleepable and normal bpf
program, so its memory is freed by using both call_rcu_tasks_trace() and
kfree_rcu() to wait for both RCU-tasks-trace grace period and RCU grace
period to expire.
However According to the current implementation of RCU-tasks-trace, one
RCU-tasks-trace grace period waits for one RCU grace period, so there is
no need to call kfree_rcu(), it is safe to call kfree() directly.
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
kernel/bpf/bpf_local_storage.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 802fc15b0d73..18a2dd611635 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -84,20 +84,26 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner,
return NULL;
}
+/* Now RCU Tasks grace period implies RCU grace period, so no need to call
+ * kfree_rcu(), just call kfree() directly.
+ */
void bpf_local_storage_free_rcu(struct rcu_head *rcu)
{
struct bpf_local_storage *local_storage;
local_storage = container_of(rcu, struct bpf_local_storage, rcu);
- kfree_rcu(local_storage, rcu);
+ kfree(local_storage);
}
+/* Now RCU Tasks grace period implies RCU grace period, so no need to call
+ * kfree_rcu(), just call kfree() directly.
+ */
static void bpf_selem_free_rcu(struct rcu_head *rcu)
{
struct bpf_local_storage_elem *selem;
selem = container_of(rcu, struct bpf_local_storage_elem, rcu);
- kfree_rcu(selem, rcu);
+ kfree(selem);
}
/* local_storage->lock must be held and selem->local_storage == local_storage.
--
2.29.2
