From: Sebastian Andrzej Siewior Date: Tue, 22 Aug 2023 18:14:44 +0200 Subject: [PATCH 09/15] dev: Remove PREEMPT_RT ifdefs from backlog_lock.*(). Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.10/older/patches-6.10.2-rt14.tar.xz 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 Since the introduction of backlog NAPI and making it mandatory for PREEMPT_RT the ifdef within backlog_lock.*() is obsolete and can be removed.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 --- net/core/dev.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/net/core/dev.c +++ b/net/core/dev.c @@ -229,7 +229,7 @@ static inline void backlog_lock_irq_save { 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); } @@ -237,7 +237,7 @@ static inline void backlog_lock_irq_disa { 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(); } @@ -246,7 +246,7 @@ static inline void backlog_unlock_irq_re { 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); } @@ -254,7 +254,7 @@ static inline void backlog_unlock_irq_en { 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(); }