Subject: Re: linux-next: build failure after merge of the bitmap tree

From: Catalin Marinas <[email-masked]>
Date: Tue, 18 Feb 2025 18:23:29 +0000

On Tue, Feb 18, 2025 at 09:16:34AM -0500, Yury Norov wrote:
> On Tue, Feb 18, 2025 at 02:10:25PM +0000, Catalin Marinas wrote:
> > Hi Stephen,
> > 
> > On Wed, Feb 19, 2025 at 12:49:34AM +1100, Stephen Rothwell wrote:
> > > On Tue, 18 Feb 2025 11:35:02 +0100 Beata Michalska <[email-masked]> wrote:
> > > > I'm currently testing a proper fix for that one.
> > > > Should I just send it over as a diff to apply or rather a proper 'fixes' patch?
> > > 
> > > Maybe a proper 'fixes' patch, please, if easy - otherwise a diff is
> > > fine.
> > 
> > I just talked to Beata off-list. I think she'll try to use the current
> > for_each_cpu_wrap() API and avoid conflicts with the cpumask_next_wrap()
> > API change.
> 
> Hi,
> 
> Yes, for_each() loops are always preferable over opencoded iterating.
> Please feel free to CC me in case I can help.

Beata is going to post the official fix but in the meantime, to avoid
breaking next, I'll add my temporary fix:

--------8<--------------------------------
>From 1b12139107798128c183838c5f4a3f7ffcea1e44 Mon Sep 17 00:00:00 2001
From: Catalin Marinas <[email-masked]>
Date: Tue, 18 Feb 2025 18:20:46 +0000
Subject: [PATCH] arm64: Do not use the deprecated cpumask_next_wrap() in
 arch_freq_get_on_cpu()

cpumask_next_wrap() will soon disappear in its current form. Use
for_each_cpu_wrap() instead.

Fixes: 16d1e27475f6 ("arm64: Provide an AMU-based version of arch_freq_get_on_cpu")
Signed-off-by: Catalin Marinas <[email-masked]>
---
 arch/arm64/kernel/topology.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index a09b0551ec59..1544d3648554 100644
--- 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 +265,10 @@ 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, start_cpu) {
+				if (!idle_cpu(ref_cpu))
+					break;
+			}

 			cpufreq_cpu_put(policy);