From: Shivnandan Kumar <quic_kshivnan@quicinc.com>
Date: Tue, 27 Feb 2024 09:13:51 +0000 (+0530)
Subject: cpufreq: Limit resolving a frequency to policy min/max
X-Git-Tag: v6.7.12~364
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=01e4e0b9e7cd36072fccc126f17de510fd4809b8;p=thirdparty%2Fkernel%2Fstable.git

cpufreq: Limit resolving a frequency to policy min/max

[ Upstream commit d394abcb12bb1a6f309c1221fdb8e73594ecf1b4 ]

Resolving a frequency to an efficient one should not transgress
policy->max (which can be set for thermal reason) and policy->min.

Currently, there is possibility where scaling_cur_freq can exceed
scaling_max_freq when scaling_max_freq is an inefficient frequency.

Add a check to ensure that resolving a frequency will respect
policy->min/max.

Cc: All applicable <stable@vger.kernel.org>
Fixes: 1f39fa0dccff ("cpufreq: Introducing CPUFREQ_RELATION_E")
Signed-off-by: Shivnandan Kumar <quic_kshivnan@quicinc.com>
[ rjw: Whitespace adjustment, changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 1c5ca92a0555f..90f8bd1736a2c 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -1021,6 +1021,18 @@ static inline int cpufreq_table_find_index_c(struct cpufreq_policy *policy,
 						   efficiencies);
 }
 
+static inline bool cpufreq_is_in_limits(struct cpufreq_policy *policy, int idx)
+{
+	unsigned int freq;
+
+	if (idx < 0)
+		return false;
+
+	freq = policy->freq_table[idx].frequency;
+
+	return freq == clamp_val(freq, policy->min, policy->max);
+}
+
 static inline int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 						 unsigned int target_freq,
 						 unsigned int relation)
@@ -1054,7 +1066,8 @@ retry:
 		return 0;
 	}
 
-	if (idx < 0 && efficiencies) {
+	/* Limit frequency index to honor policy->min/max */
+	if (!cpufreq_is_in_limits(policy, idx) && efficiencies) {
 		efficiencies = false;
 		goto retry;
 	}