netdev - [PATCH net-next] net: fully inline backlog_unlock_irq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260105163054.13698-1-edumazet@google.com>
Date: Mon,  5 Jan 2026 16:30:54 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>
Cc: Simon Horman <horms@...nel.org>, netdev@...r.kernel.org, eric.dumazet@...il.com, 
	Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next] net: fully inline backlog_unlock_irq_restore()

Some arches (like x86) do not inline spin_unlock_irqrestore().

backlog_unlock_irq_restore() is in RPS/RFS critical path,
we prefer using spin_unlock() + local_irq_restore() for
optimal performance.

Also change backlog_unlock_irq_restore() second argument
to avoid a pointless dereference.

No difference in net/core/dev.o code size.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/core/dev.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 36dc5199037e..c711da335510 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -246,12 +246,11 @@ static inline void backlog_lock_irq_disable(struct softnet_data *sd)
 }
 
 static inline void backlog_unlock_irq_restore(struct softnet_data *sd,
-					      unsigned long *flags)
+					      unsigned long flags)
 {
 	if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads())
-		spin_unlock_irqrestore(&sd->input_pkt_queue.lock, *flags);
-	else
-		local_irq_restore(*flags);
+		spin_unlock(&sd->input_pkt_queue.lock);
+	local_irq_restore(flags);
 }
 
 static inline void backlog_unlock_irq_enable(struct softnet_data *sd)
@@ -5247,7 +5246,7 @@ void kick_defer_list_purge(unsigned int cpu)
 		if (!__test_and_set_bit(NAPI_STATE_SCHED, &sd->backlog.state))
 			__napi_schedule_irqoff(&sd->backlog);
 
-		backlog_unlock_irq_restore(sd, &flags);
+		backlog_unlock_irq_restore(sd, flags);
 
 	} else if (!cmpxchg(&sd->defer_ipi_scheduled, 0, 1)) {
 		smp_call_function_single_async(cpu, &sd->defer_csd);
@@ -5334,14 +5333,14 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
 		}
 		__skb_queue_tail(&sd->input_pkt_queue, skb);
 		tail = rps_input_queue_tail_incr(sd);
-		backlog_unlock_irq_restore(sd, &flags);
+		backlog_unlock_irq_restore(sd, flags);
 
 		/* save the tail outside of the critical section */
 		rps_input_queue_tail_save(qtail, tail);
 		return NET_RX_SUCCESS;
 	}
 
-	backlog_unlock_irq_restore(sd, &flags);
+	backlog_unlock_irq_restore(sd, flags);
 
 cpu_backlog_drop:
 	reason = SKB_DROP_REASON_CPU_BACKLOG;
-- 
2.52.0.351.gbe84eed79e-goog