Commit 1462160c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: adopt try_cmpxchg() in napi_schedule_prep() and napi_complete_done() 



This makes the code slightly more efficient.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6af645a5

net/core/dev.c

+4 −6
Original line number Diff line number Diff line
@@ -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);

	}



	do {

	val = READ_ONCE(n->state);



	do {

		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);