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| author |   KP Singh <kpsingh@kernel.org> | 2021-12-24 15:29:15 +0000 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2021-12-29 17:54:40 -0800 |
| commit | 0fe4b381a59ebc53522fce579b281a67a9e1bee6 (patch) | |
| tree | cc021f1fa576f3871281c14ff624782a3b4dc7c6 /kernel/bpf/verifier.c | |
| parent | bpf: Add missing map_get_next_key method to bloom filter map. (diff) | |
| download | linux-dev-0fe4b381a59ebc53522fce579b281a67a9e1bee6.tar.xz linux-dev-0fe4b381a59ebc53522fce579b281a67a9e1bee6.zip | |
bpf: Allow bpf_local_storage to be used by sleepable programs
Other maps like hashmaps are already available to sleepable programs.
Sleepable BPF programs run under trace RCU. Allow task, sk and inode
storage to be used from sleepable programs. This allows sleepable and
non-sleepable programs to provide shareable annotations on kernel
objects.
Sleepable programs run in trace RCU where as non-sleepable programs run
in a normal RCU critical section i.e. __bpf_prog_enter{_sleepable}
and __bpf_prog_exit{_sleepable}) (rcu_read_lock or rcu_read_lock_trace).
In order to make the local storage maps accessible to both sleepable
and non-sleepable programs, one needs to call both
call_rcu_tasks_trace and call_rcu to wait for both trace and classical
RCU grace periods to expire before freeing memory.
Paul's work on call_rcu_tasks_trace allows us to have per CPU queueing
for call_rcu_tasks_trace. This behaviour can be achieved by setting
rcupdate.rcu_task_enqueue_lim=<num_cpus> boot parameter.
In light of these new performance changes and to keep the local storage
code simple, avoid adding a new flag for sleepable maps / local storage
to select the RCU synchronization (trace / classical).
Also, update the dereferencing of the pointers to use
rcu_derference_check (with either the trace or normal RCU locks held)
with a common bpf_rcu_lock_held helper method.
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20211224152916.1550677-2-kpsingh@kernel.org
Diffstat (limited to '')
| -rw-r--r-- | kernel/bpf/verifier.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ca5cd0de804c..133599dfe2a2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11874,6 +11874,9 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, } break; case BPF_MAP_TYPE_RINGBUF: + case BPF_MAP_TYPE_INODE_STORAGE: + case BPF_MAP_TYPE_SK_STORAGE: + case BPF_MAP_TYPE_TASK_STORAGE: break; default: verbose(env, |