ipv4/route: Use this_cpu_inc() for stats on PREEMPT_RT

The statistics are incremented with raw_cpu_inc() assuming it always
happens with bottom half disabled. Without per-CPU locking in
local_bh_disable() on PREEMPT_RT this is no longer true.

Use this_cpu_inc() on PREEMPT_RT for the increment to not worry about
preemption.

Cc: David Ahern <dsahern@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20250512092736.229935-4-bigeasy@linutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 507b2e5dec50f7dbf9d35d8d8bbbb15de61834b2..fccb05fb3a794bdb71456f5cd38d9ec0b9665c43 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -189,7 +189,11 @@ const __u8 ip_tos2prio[16] = {
 EXPORT_SYMBOL(ip_tos2prio);
 
 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
+#ifndef CONFIG_PREEMPT_RT
 #define RT_CACHE_STAT_INC(field) raw_cpu_inc(rt_cache_stat.field)
+#else
+#define RT_CACHE_STAT_INC(field) this_cpu_inc(rt_cache_stat.field)
+#endif
 
 #ifdef CONFIG_PROC_FS
 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)