[PATCH v1 1/2] riscv: cpu_ops: Change return value type of cpu_is_stopped() to bool

[Hui Wang]

In the original sbi_cpu_is_stopped(), if rc doesn't equal to the
SBI_HSM_STATE_STOPPED, it will return rc to the caller directly. But
there is a hidden problem, the rc could be SBI_HSM_STATE_STARTED, if
so, this function will report cpu stopped while the cpu isn't really
stopped.

Furthermore, from the name of cpu_is_stopped(), it gives a sense the
return value is a bool type, true means the cpu is stopped, conversely
false means the cpu is not stopped.

Here change the return value type to bool and change the callers
accordingly. This could fix the above two issues.

Fixes: f1e58583b9c7c ("RISC-V: Support cpu hotplug")
Signed-off-by: Hui Wang <hui.wang at canonical.com>
---
In the v1:
move the cpu status number printing from arch_cpuhp_cleanup_dead_cpu()
to sbi_cpu_is_stopped().

 arch/riscv/include/asm/cpu_ops.h |  2 +-
 arch/riscv/kernel/cpu-hotplug.c  |  4 ++--
 arch/riscv/kernel/cpu_ops_sbi.c  | 11 +++++++----
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/arch/riscv/include/asm/cpu_ops.h b/arch/riscv/include/asm/cpu_ops.h
index 176b570ef982..065811fca594 100644
--- a/arch/riscv/include/asm/cpu_ops.h
+++ b/arch/riscv/include/asm/cpu_ops.h
@@ -24,7 +24,7 @@ struct cpu_operations {
 				     struct task_struct *tidle);
 #ifdef CONFIG_HOTPLUG_CPU
 	void		(*cpu_stop)(void);
-	int		(*cpu_is_stopped)(unsigned int cpu);
+	bool		(*cpu_is_stopped)(unsigned int cpu);
 #endif
 };
 
diff --git a/arch/riscv/kernel/cpu-hotplug.c b/arch/riscv/kernel/cpu-hotplug.c
index a0ee426f6d93..3b9fa03f02a9 100644
--- a/arch/riscv/kernel/cpu-hotplug.c
+++ b/arch/riscv/kernel/cpu-hotplug.c
@@ -57,8 +57,8 @@ void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
 	/* Verify from the firmware if the cpu is really stopped*/
 	if (cpu_ops->cpu_is_stopped)
 		ret = cpu_ops->cpu_is_stopped(cpu);
-	if (ret)
-		pr_warn("CPU%u may not have stopped: %d\n", cpu, ret);
+	if (!ret)
+		pr_warn("CPU%u may not have stopped.\n", cpu);
 }
 
 /*
diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c
index 00aff669f5f2..b6de2b2f8deb 100644
--- a/arch/riscv/kernel/cpu_ops_sbi.c
+++ b/arch/riscv/kernel/cpu_ops_sbi.c
@@ -88,16 +88,19 @@ static void sbi_cpu_stop(void)
 	pr_crit("Unable to stop the cpu %d (%d)\n", smp_processor_id(), ret);
 }
 
-static int sbi_cpu_is_stopped(unsigned int cpuid)
+static bool sbi_cpu_is_stopped(unsigned int cpuid)
 {
 	int rc;
 	unsigned long hartid = cpuid_to_hartid_map(cpuid);
 
 	rc = sbi_hsm_hart_get_status(hartid);
 
-	if (rc == SBI_HSM_STATE_STOPPED)
-		return 0;
-	return rc;
+	if (rc != SBI_HSM_STATE_STOPPED) {
+		pr_warn("HART%lu isn't stopped and the status number is: %d\n", hartid, rc);
+		return false;
+	}
+
+	return true;
 }
 #endif
 
-- 
2.43.0