arm64: Utilize for_each_cpu_wrap for reference lookup

While searching for a reference CPU within a given policy,
arch_freq_get_on_cpu relies on cpumask_next_wrap to iterate over
all available CPUs and to ensure each is verified only once.
Recent changes to cpumask_next_wrap will handle the latter no more,
so switching to for_each_cpu_wrap, which  preserves expected behavior
while ensuring compatibility with the updates.
Not to mention that when iterating over each CPU, using a dedicated
iterator is preferable to an open-coded loop.

Fixes: 16d1e27475f6 ("arm64: Provide an AMU-based version of arch_freq_get_on_cpu")
Signed-off-by: Beata Michalska <beata.michalska@arm.com>
Link: https://lore.kernel.org/r/20250220091015.2319901-1-beata.michalska@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index a09b0551ec59f67d008a555d6adb3b82a13abbf5..9e3583720668a4eb2107afa82fd13f3a2e8fabae 100644 (file)
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -254,7 +254,7 @@ int arch_freq_get_on_cpu(int cpu)
                if (!housekeeping_cpu(cpu, HK_TYPE_TICK) ||
                    time_is_before_jiffies(last_update + msecs_to_jiffies(AMU_SAMPLE_EXP_MS))) {
                        struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
-                       int ref_cpu = cpu;
+                       int ref_cpu;
 
                        if (!policy)
                                return -EINVAL;
@@ -265,11 +265,15 @@ int arch_freq_get_on_cpu(int cpu)
                                return -EOPNOTSUPP;
                        }
 
-                       do {
-                               ref_cpu = cpumask_next_wrap(ref_cpu, policy->cpus,
-                                                           start_cpu, true);
-
-                       } while (ref_cpu < nr_cpu_ids && idle_cpu(ref_cpu));
+                       for_each_cpu_wrap(ref_cpu, policy->cpus, cpu + 1) {
+                               if (ref_cpu == start_cpu) {
+                                       /* Prevent verifying same CPU twice */
+                                       ref_cpu = nr_cpu_ids;
+                                       break;
+                               }
+                               if (!idle_cpu(ref_cpu))
+                                       break;
+                       }
 
                        cpufreq_cpu_put(policy);