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bpf: Fix usage of trace RCU in local storage.

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bpf_{sk,task,inode}_storage_free() do not need to use
call_rcu_tasks_trace as no BPF program should be accessing the owner
as it's being destroyed. The only other reader at this point is
bpf_local_storage_map_free() which uses normal RCU.

The only path that needs trace RCU are:

* bpf_local_storage_{delete,update} helpers
* map_{delete,update}_elem() syscalls

Fixes: 0fe4b381a5 ("bpf: Allow bpf_local_storage to be used by sleepable programs")
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/20220418155158.2865678-1-kpsingh@kernel.org
This commit is contained in:
KP Singh
2022-04-18 15:51:58 +00:00
committed by Alexei Starovoitov
parent 0e5aefa334
commit dcf456c9a0
5 changed files with 28 additions and 19 deletions
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4
include/linux/bpf_local_storage.h
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@@ -143,9 +143,9 @@ void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
struct bpf_local_storage_elem *selem,
bool uncharge_omem);
bool uncharge_omem, bool use_trace_rcu);
void bpf_selem_unlink(struct bpf_local_storage_elem *selem);
void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu);
void bpf_selem_link_map(struct bpf_local_storage_map *smap,
struct bpf_local_storage_elem *selem);