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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
	Daniel Bristot de Oliveira <bristot@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Eric Dumazet <edumazet@google.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Waiman Long <longman@redhat.com>,
	Will Deacon <will@kernel.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH v4 net-next 08/14] dev: Remove PREEMPT_RT ifdefs from backlog_lock.*().
Date: Tue,  4 Jun 2024 17:24:15 +0200
Message-ID: <20240604154425.878636-9-bigeasy@linutronix.de>
In-Reply-To: <20240604154425.878636-1-bigeasy@linutronix.de>
References: <20240604154425.878636-1-bigeasy@linutronix.de>
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The backlog_napi locking (previously RPS) relies on explicit locking if
either RPS or backlog NAPI is enabled. If both are disabled then locking
was achieved by disabling interrupts except on PREEMPT_RT. PREEMPT_RT
was excluded because the needed synchronisation was already provided
local_bh_disable().

Since the introduction of backlog NAPI and making it mandatory for
PREEMPT_RT the ifdef within backlog_lock.*() is obsolete and can be
removed.

Remove the ifdefs in backlog_lock.*().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 net/core/dev.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 85fe8138f3e4e..a66e4e744bbb4 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -229,7 +229,7 @@ static inline void backlog_lock_irq_save(struct softnet=
_data *sd,
 {
 	if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads())
 		spin_lock_irqsave(&sd->input_pkt_queue.lock, *flags);
-	else if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+	else
 		local_irq_save(*flags);
 }
=20
@@ -237,7 +237,7 @@ static inline void backlog_lock_irq_disable(struct soft=
net_data *sd)
 {
 	if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads())
 		spin_lock_irq(&sd->input_pkt_queue.lock);
-	else if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+	else
 		local_irq_disable();
 }
=20
@@ -246,7 +246,7 @@ static inline void backlog_unlock_irq_restore(struct so=
ftnet_data *sd,
 {
 	if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads())
 		spin_unlock_irqrestore(&sd->input_pkt_queue.lock, *flags);
-	else if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+	else
 		local_irq_restore(*flags);
 }
=20
@@ -254,7 +254,7 @@ static inline void backlog_unlock_irq_enable(struct sof=
tnet_data *sd)
 {
 	if (IS_ENABLED(CONFIG_RPS) || use_backlog_threads())
 		spin_unlock_irq(&sd->input_pkt_queue.lock);
-	else if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+	else
 		local_irq_enable();
 }
=20
--=20
2.45.1