From 1462160c7455cfc495693e47d0eabb371ec4f7ff Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 15 Nov 2022 09:10:59 +0000 Subject: [PATCH] net: adopt try_cmpxchg() in napi_schedule_prep() and napi_complete_done() This makes the code slightly more efficient. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 10b5664..0c12c7a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5979,10 +5979,9 @@ EXPORT_SYMBOL(__napi_schedule); */ bool napi_schedule_prep(struct napi_struct *n) { - unsigned long val, new; + unsigned long new, val = READ_ONCE(n->state); do { - val = READ_ONCE(n->state); if (unlikely(val & NAPIF_STATE_DISABLE)) return false; new = val | NAPIF_STATE_SCHED; @@ -5995,7 +5994,7 @@ bool napi_schedule_prep(struct napi_struct *n) */ new |= (val & NAPIF_STATE_SCHED) / NAPIF_STATE_SCHED * NAPIF_STATE_MISSED; - } while (cmpxchg(&n->state, val, new) != val); + } while (!try_cmpxchg(&n->state, &val, new)); return !(val & NAPIF_STATE_SCHED); } @@ -6063,9 +6062,8 @@ bool napi_complete_done(struct napi_struct *n, int work_done) local_irq_restore(flags); } + val = READ_ONCE(n->state); do { - val = READ_ONCE(n->state); - WARN_ON_ONCE(!(val & NAPIF_STATE_SCHED)); new = val & ~(NAPIF_STATE_MISSED | NAPIF_STATE_SCHED | @@ -6078,7 +6076,7 @@ bool napi_complete_done(struct napi_struct *n, int work_done) */ new |= (val & NAPIF_STATE_MISSED) / NAPIF_STATE_MISSED * NAPIF_STATE_SCHED; - } while (cmpxchg(&n->state, val, new) != val); + } while (!try_cmpxchg(&n->state, &val, new)); if (unlikely(val & NAPIF_STATE_MISSED)) { __napi_schedule(n); -- 2.7.4