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authorHou Tao <houtao1@huawei.com>2022-10-14 19:39:45 +0800
committerAlexei Starovoitov <ast@kernel.org>2022-10-18 10:27:02 -0700
commitd39d1445d37747032e2b26732fed6fe25161cd36 (patch)
treec7d7ca9a9cd280148fea567c5d7036076c574b48 /kernel/bpf/bpf_local_storage.c
parent59be91e5e70a1aa91dfee8088b071f6d05c8a1a3 (diff)
bpf: Use rcu_trace_implies_rcu_gp() in local storage map
Local storage map is accessible for both sleepable and non-sleepable bpf program, and 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 pass. With the introduction of rcu_trace_implies_rcu_gp(), both bpf_selem_free_rcu() and bpf_local_storage_free_rcu() can check whether or not a normal RCU grace period has also passed after a RCU-tasks-trace grace period has passed. If it is true, it is safe to call kfree() directly. Signed-off-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/r/20221014113946.965131-4-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/bpf_local_storage.c')
-rw-r--r--kernel/bpf/bpf_local_storage.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 802fc15b0d73..9dc6de1cf185 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -88,8 +88,14 @@ void bpf_local_storage_free_rcu(struct rcu_head *rcu)
{
struct bpf_local_storage *local_storage;
+ /* If RCU Tasks Trace grace period implies RCU grace period, do
+ * kfree(), else do kfree_rcu().
+ */
local_storage = container_of(rcu, struct bpf_local_storage, rcu);
- kfree_rcu(local_storage, rcu);
+ if (rcu_trace_implies_rcu_gp())
+ kfree(local_storage);
+ else
+ kfree_rcu(local_storage, rcu);
}
static void bpf_selem_free_rcu(struct rcu_head *rcu)
@@ -97,7 +103,10 @@ 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);
+ if (rcu_trace_implies_rcu_gp())
+ kfree(selem);
+ else
+ kfree_rcu(selem, rcu);
}
/* local_storage->lock must be held and selem->local_storage == local_storage.