diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2024-06-20 15:21:55 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-06-25 01:41:22 +0200 |
| commit | 585aa621af6cd11d3d6f830965af3e45ee79ea51 (patch) | |
| tree | 4974e3703e095ffcc2f0e2e11036b4c02a9e7cf9 /net/ipv4 | |
| parent | net: Use nested-BH locking for napi_alloc_cache. (diff) | |
| download | linux-585aa621af6cd11d3d6f830965af3e45ee79ea51.tar.xz linux-585aa621af6cd11d3d6f830965af3e45ee79ea51.zip | |
net/tcp_sigpool: Use nested-BH locking for sigpool_scratch.
sigpool_scratch 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.
Make a struct with a pad member (original sigpool_scratch) and a
local_lock_t 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: David Ahern <dsahern@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20240620132727.660738-6-bigeasy@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp_sigpool.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/net/ipv4/tcp_sigpool.c b/net/ipv4/tcp_sigpool.c index 8512cb09ebc0..d8a4f192873a 100644 --- a/net/ipv4/tcp_sigpool.c +++ b/net/ipv4/tcp_sigpool.c @@ -10,7 +10,14 @@ #include <net/tcp.h> static size_t __scratch_size; -static DEFINE_PER_CPU(void __rcu *, sigpool_scratch); +struct sigpool_scratch { + local_lock_t bh_lock; + void __rcu *pad; +}; + +static DEFINE_PER_CPU(struct sigpool_scratch, sigpool_scratch) = { + .bh_lock = INIT_LOCAL_LOCK(bh_lock), +}; struct sigpool_entry { struct crypto_ahash *hash; @@ -72,7 +79,7 @@ static int sigpool_reserve_scratch(size_t size) break; } - old_scratch = rcu_replace_pointer(per_cpu(sigpool_scratch, cpu), + old_scratch = rcu_replace_pointer(per_cpu(sigpool_scratch.pad, cpu), scratch, lockdep_is_held(&cpool_mutex)); if (!cpu_online(cpu) || !old_scratch) { kfree(old_scratch); @@ -93,7 +100,7 @@ static void sigpool_scratch_free(void) int cpu; for_each_possible_cpu(cpu) - kfree(rcu_replace_pointer(per_cpu(sigpool_scratch, cpu), + kfree(rcu_replace_pointer(per_cpu(sigpool_scratch.pad, cpu), NULL, lockdep_is_held(&cpool_mutex))); __scratch_size = 0; } @@ -277,7 +284,8 @@ int tcp_sigpool_start(unsigned int id, struct tcp_sigpool *c) __cond_acquires(RC /* Pairs with tcp_sigpool_reserve_scratch(), scratch area is * valid (allocated) until tcp_sigpool_end(). */ - c->scratch = rcu_dereference_bh(*this_cpu_ptr(&sigpool_scratch)); + local_lock_nested_bh(&sigpool_scratch.bh_lock); + c->scratch = rcu_dereference_bh(*this_cpu_ptr(&sigpool_scratch.pad)); return 0; } EXPORT_SYMBOL_GPL(tcp_sigpool_start); @@ -286,6 +294,7 @@ void tcp_sigpool_end(struct tcp_sigpool *c) __releases(RCU_BH) { struct crypto_ahash *hash = crypto_ahash_reqtfm(c->req); + local_unlock_nested_bh(&sigpool_scratch.bh_lock); rcu_read_unlock_bh(); ahash_request_free(c->req); crypto_free_ahash(hash); |