From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juri Lelli Subject: [RFC PATCH 02/19] cpufreq: merge governor lock and mutex Date: Mon, 11 Jan 2016 17:35:43 +0000 Message-ID: <1452533760-13787-3-git-send-email-juri.lelli@arm.com> References: <1452533760-13787-1-git-send-email-juri.lelli@arm.com> Return-path: In-Reply-To: <1452533760-13787-1-git-send-email-juri.lelli@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org, peterz@infradead.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, mturquette@baylibre.com, steve.muckle@linaro.org, vincent.guittot@linaro.org, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, juri.lelli@arm.com List-Id: linux-pm@vger.kernel.org From: Michael Turquette Commit 95731ebb114c ("cpufreq: Fix governor start/stop race condition") introduced cpufreq_governor_lock. This was actually overkilling, as the same can be achieved by using the existing cpufreq_governor_mutex. Removing cpufreq_governor_lock cleans things up and makes deadlocks less likely to happen. Cc: "Rafael J. Wysocki" Cc: Viresh Kumar Signed-off-by: Michael Turquette --- drivers/cpufreq/cpufreq.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 7bdd845..0802705 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -102,7 +102,7 @@ static LIST_HEAD(cpufreq_governor_list); static struct cpufreq_driver *cpufreq_driver; static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); static DEFINE_RWLOCK(cpufreq_driver_lock); -static DEFINE_MUTEX(cpufreq_governor_lock); +static DEFINE_MUTEX(cpufreq_governor_mutex); /* Flag to suspend/resume CPUFreq governors */ static bool cpufreq_suspended; @@ -146,7 +146,6 @@ void disable_cpufreq(void) { off = 1; } -static DEFINE_MUTEX(cpufreq_governor_mutex); bool have_governor_per_policy(void) { @@ -1963,11 +1962,11 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event); - mutex_lock(&cpufreq_governor_lock); + mutex_lock(&cpufreq_governor_mutex); if ((policy->governor_enabled && event == CPUFREQ_GOV_START) || (!policy->governor_enabled && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { - mutex_unlock(&cpufreq_governor_lock); + mutex_unlock(&cpufreq_governor_mutex); return -EBUSY; } @@ -1976,7 +1975,7 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, else if (event == CPUFREQ_GOV_START) policy->governor_enabled = true; - mutex_unlock(&cpufreq_governor_lock); + mutex_unlock(&cpufreq_governor_mutex); ret = policy->governor->governor(policy, event); @@ -1987,12 +1986,12 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->governor->initialized--; } else { /* Restore original values */ - mutex_lock(&cpufreq_governor_lock); + mutex_lock(&cpufreq_governor_mutex); if (event == CPUFREQ_GOV_STOP) policy->governor_enabled = true; else if (event == CPUFREQ_GOV_START) policy->governor_enabled = false; - mutex_unlock(&cpufreq_governor_lock); + mutex_unlock(&cpufreq_governor_mutex); } if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || -- 2.2.2