processor: get rid of cpu_relax_yield

stop_machine is the only user left of cpu_relax_yield. Given that it
now has special semantics which are tied to stop_machine introduce a
weak stop_machine_yield function which architectures can override, and
get rid of the generic cpu_relax_yield implementation.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

2 files changed, 2 insertions, 8 deletions

diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 445ce9ee4404..14883b1562e0 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -222,12 +222,6 @@ static __no_kasan_or_inline unsigned short stap(void)
 	return cpu_address;
 }
 
-/*
- * Give up the time slice of the virtual PU.
- */
-#define cpu_relax_yield cpu_relax_yield
-void cpu_relax_yield(const struct cpumask *cpumask);
-
 #define cpu_relax() barrier()
 
 #define ECAG_CACHE_ATTRIBUTE	0
diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c
index 4cdaefec1b7c..6ebc2117c66c 100644
--- a/arch/s390/kernel/processor.c
+++ b/arch/s390/kernel/processor.c
@@ -7,6 +7,7 @@
 #define KMSG_COMPONENT "cpu"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
+#include <linux/stop_machine.h>
 #include <linux/cpufeature.h>
 #include <linux/bitops.h>
 #include <linux/kernel.h>
@@ -59,7 +60,7 @@ void s390_update_cpu_mhz(void)
 		on_each_cpu(update_cpu_mhz, NULL, 0);
 }
 
-void notrace cpu_relax_yield(const struct cpumask *cpumask)
+void notrace stop_machine_yield(const struct cpumask *cpumask)
 {
 	int cpu, this_cpu;
 
@@ -73,7 +74,6 @@ void notrace cpu_relax_yield(const struct cpumask *cpumask)
 			smp_yield_cpu(cpu);
 	}
 }
-EXPORT_SYMBOL(cpu_relax_yield);
 
 /*
  * cpu_init - initializes state that is per-CPU.