[PATCH v5 5/5] rqspinlock: Use smp_cond_load_acquire_timeout()
From: Ankur Arora <hidden>
Date: 2025-09-11 03:47:29
Also in:
bpf, linux-arch, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Switch out the conditional load inerfaces used by rqspinlock to smp_cond_read_acquire_timeout(). This interface handles the timeout check explicitly and does any necessary amortization, so use check_timeout() directly. Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Ankur Arora <redacted> --- kernel/bpf/rqspinlock.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-)
diff --git a/kernel/bpf/rqspinlock.c b/kernel/bpf/rqspinlock.c
index 5ab354d55d82..4d2c12d131ae 100644
--- a/kernel/bpf/rqspinlock.c
+++ b/kernel/bpf/rqspinlock.c@@ -241,20 +241,14 @@ static noinline int check_timeout(rqspinlock_t *lock, u32 mask, } /* - * Do not amortize with spins when res_smp_cond_load_acquire is defined, - * as the macro does internal amortization for us. + * Amortize timeout check for busy-wait loops. */ -#ifndef res_smp_cond_load_acquire #define RES_CHECK_TIMEOUT(ts, ret, mask) \ ({ \ if (!(ts).spin++) \ (ret) = check_timeout((lock), (mask), &(ts)); \ (ret); \ }) -#else -#define RES_CHECK_TIMEOUT(ts, ret, mask) \ - ({ (ret) = check_timeout((lock), (mask), &(ts)); }) -#endif /* * Initialize the 'spin' member.
@@ -313,11 +307,8 @@ EXPORT_SYMBOL_GPL(resilient_tas_spin_lock); */ static DEFINE_PER_CPU_ALIGNED(struct qnode, rqnodes[_Q_MAX_NODES]); -#ifndef res_smp_cond_load_acquire -#define res_smp_cond_load_acquire(v, c) smp_cond_load_acquire(v, c) -#endif - -#define res_atomic_cond_read_acquire(v, c) res_smp_cond_load_acquire(&(v)->counter, (c)) +#define res_atomic_cond_read_acquire_timeout(v, c, t) \ + smp_cond_load_acquire_timeout(&(v)->counter, (c), (t)) /** * resilient_queued_spin_lock_slowpath - acquire the queued spinlock
@@ -418,7 +409,8 @@ int __lockfunc resilient_queued_spin_lock_slowpath(rqspinlock_t *lock, u32 val) */ if (val & _Q_LOCKED_MASK) { RES_RESET_TIMEOUT(ts, RES_DEF_TIMEOUT); - res_smp_cond_load_acquire(&lock->locked, !VAL || RES_CHECK_TIMEOUT(ts, ret, _Q_LOCKED_MASK)); + smp_cond_load_acquire_timeout(&lock->locked, !VAL, + (ret = check_timeout(lock, _Q_LOCKED_MASK, &ts))); } if (ret) {
@@ -572,9 +564,8 @@ int __lockfunc resilient_queued_spin_lock_slowpath(rqspinlock_t *lock, u32 val) * us. */ RES_RESET_TIMEOUT(ts, RES_DEF_TIMEOUT * 2); - val = res_atomic_cond_read_acquire(&lock->val, !(VAL & _Q_LOCKED_PENDING_MASK) || - RES_CHECK_TIMEOUT(ts, ret, _Q_LOCKED_PENDING_MASK)); - + val = res_atomic_cond_read_acquire_timeout(&lock->val, !(VAL & _Q_LOCKED_PENDING_MASK), + (ret = check_timeout(lock, _Q_LOCKED_PENDING_MASK, &ts))); waitq_timeout: if (ret) { /*
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2.43.5