diff options
| author | Sebastian Andrzej Siewior <[email protected]> | 2024-06-20 15:22:03 +0200 |
|---|---|---|
| committer | Jakub Kicinski <[email protected]> | 2024-06-24 16:41:23 -0700 |
| commit | 78f520b7bbe579438dfc202226b3dac5607d8c7f (patch) | |
| tree | 5153f67a77881d0cb30315535265f04093828146 | |
| parent | d1542d4ae4dfdc47c9b3205ebe849ed23af213dd (diff) | |
net: Use nested-BH locking for bpf_scratchpad.
bpf_scratchpad is a per-CPU variable and relies on disabled BH for its
locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
this data structure requires explicit locking.
Add a local_lock_t to the data structure and use local_lock_nested_bh()
for locking. This change adds only lockdep coverage and does not alter
the functional behaviour for !PREEMPT_RT.
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Hao Luo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Stanislav Fomichev <[email protected]>
Cc: Yonghong Song <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
| -rw-r--r-- | net/core/filter.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index c4f5db324f04..adb887195c3a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1658,9 +1658,12 @@ struct bpf_scratchpad { __be32 diff[MAX_BPF_STACK / sizeof(__be32)]; u8 buff[MAX_BPF_STACK]; }; + local_lock_t bh_lock; }; -static DEFINE_PER_CPU(struct bpf_scratchpad, bpf_sp); +static DEFINE_PER_CPU(struct bpf_scratchpad, bpf_sp) = { + .bh_lock = INIT_LOCAL_LOCK(bh_lock), +}; static inline int __bpf_try_make_writable(struct sk_buff *skb, unsigned int write_len) @@ -2021,6 +2024,7 @@ BPF_CALL_5(bpf_csum_diff, __be32 *, from, u32, from_size, struct bpf_scratchpad *sp = this_cpu_ptr(&bpf_sp); u32 diff_size = from_size + to_size; int i, j = 0; + __wsum ret; /* This is quite flexible, some examples: * @@ -2034,12 +2038,15 @@ BPF_CALL_5(bpf_csum_diff, __be32 *, from, u32, from_size, diff_size > sizeof(sp->diff))) return -EINVAL; + local_lock_nested_bh(&bpf_sp.bh_lock); for (i = 0; i < from_size / sizeof(__be32); i++, j++) sp->diff[j] = ~from[i]; for (i = 0; i < to_size / sizeof(__be32); i++, j++) sp->diff[j] = to[i]; - return csum_partial(sp->diff, diff_size, seed); + ret = csum_partial(sp->diff, diff_size, seed); + local_unlock_nested_bh(&bpf_sp.bh_lock); + return ret; } static const struct bpf_func_proto bpf_csum_diff_proto = { |