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Subject[PATCH v2] cpufreq: Make cpufreq_online() call driver->offline() on errors
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Subject: [PATCH] cpufreq: Make cpufreq_online() call driver->offline() on errors

In the CPU removal path the ->offline() callback provided by the
driver is always invoked before ->exit(), but in the cpufreq_online()
error path it is not, so ->exit() is expected to somehow know the
context in which it has been called and act accordingly.

That is less than straightforward, so make cpufreq_online() invoke
the driver's ->offline() callback, if present, on errors before
->exit() too.

This only potentially affects intel_pstate.

Fixes: 91a12e91dc39 ("cpufreq: Allow light-weight tear down and bring up of CPUs")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

-> v2:
* Avoid calling ->offline() after a failing ->online().
* Add a comment regarding the expected state after calling ->init().
* Edit the changelog a bit.

---
drivers/cpufreq/cpufreq.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -1367,9 +1367,14 @@ static int cpufreq_online(unsigned int c
goto out_free_policy;
}

+ /*
+ * The initialization has succeeded and the policy is online.
+ * If there is a problem with its frequency table, take it
+ * offline and drop it.
+ */
ret = cpufreq_table_validate_and_sort(policy);
if (ret)
- goto out_exit_policy;
+ goto out_offline_policy;

/* related_cpus should at least include policy->cpus. */
cpumask_copy(policy->related_cpus, policy->cpus);
@@ -1515,6 +1520,10 @@ out_destroy_policy:

up_write(&policy->rwsem);

+out_offline_policy:
+ if (cpufreq_driver->offline)
+ cpufreq_driver->offline(policy);
+
out_exit_policy:
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);


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