target/linux/brcm2708/patches-4.19/950-0759-cpufreq-scpi-scmi-Fix-freeing-of-dynamic-OPPs.patch

   1 From 84a8cbf64731568c0750137ec38091a46b81d502 Mon Sep 17 00:00:00 2001
   2 From: Viresh Kumar <viresh.kumar@linaro.org>
   3 Date: Fri, 4 Jan 2019 15:14:33 +0530
   4 Subject: [PATCH] cpufreq: scpi/scmi: Fix freeing of dynamic OPPs
   5
   6 Commit 1690d8bb91e370ab772062b79bd434ce815c4729 upstream
   7
   8 Since the commit 2a4eb7358aba "OPP: Don't remove dynamic OPPs from
   9 _dev_pm_opp_remove_table()", dynamically created OPP aren't
  10 automatically removed anymore by dev_pm_opp_cpumask_remove_table(). This
  11 affects the scpi and scmi cpufreq drivers which no longer free OPPs on
  12 failures or on invocations of the policy->exit() callback.
  13
  14 Create a generic OPP helper dev_pm_opp_remove_all_dynamic() which can be
  15 called from these drivers instead of dev_pm_opp_cpumask_remove_table().
  16
  17 In dev_pm_opp_remove_all_dynamic(), we need to make sure that the
  18 opp_list isn't getting accessed simultaneously from other parts of the
  19 OPP core while the helper is freeing dynamic OPPs, i.e. we can't drop
  20 the opp_table->lock while traversing through the OPP list. And to
  21 accomplish that, this patch also creates _opp_kref_release_unlocked()
  22 which can be called from this new helper with the opp_table lock already
  23 held.
  24
  25 Cc: 4.20 <stable@vger.kernel.org> # v4.20
  26 Reported-by: Valentin Schneider <valentin.schneider@arm.com>
  27 Fixes: 2a4eb7358aba "OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()"
  28 Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
  29 Tested-by: Valentin Schneider <valentin.schneider@arm.com>
  30 Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
  31 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  32 ---
  33  drivers/cpufreq/scmi-cpufreq.c |  4 +--
  34  drivers/cpufreq/scpi-cpufreq.c |  4 +--
  35  drivers/opp/core.c             | 63 +++++++++++++++++++++++++++++++---
  36  include/linux/pm_opp.h         |  5 +++
  37  4 files changed, 67 insertions(+), 9 deletions(-)
  38
  39 --- a/drivers/cpufreq/scmi-cpufreq.c
  40 +++ b/drivers/cpufreq/scmi-cpufreq.c
  41 @@ -176,7 +176,7 @@ static int scmi_cpufreq_init(struct cpuf
  42  out_free_priv:
  43         kfree(priv);
  44  out_free_opp:
  45 -       dev_pm_opp_cpumask_remove_table(policy->cpus);
  46 +       dev_pm_opp_remove_all_dynamic(cpu_dev);
  47
  48         return ret;
  49  }
  50 @@ -188,7 +188,7 @@ static int scmi_cpufreq_exit(struct cpuf
  51         cpufreq_cooling_unregister(priv->cdev);
  52         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
  53         kfree(priv);
  54 -       dev_pm_opp_cpumask_remove_table(policy->related_cpus);
  55 +       dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
  56
  57         return 0;
  58  }
  59 --- a/drivers/cpufreq/scpi-cpufreq.c
  60 +++ b/drivers/cpufreq/scpi-cpufreq.c
  61 @@ -177,7 +177,7 @@ out_free_cpufreq_table:
  62  out_free_priv:
  63         kfree(priv);
  64  out_free_opp:
  65 -       dev_pm_opp_cpumask_remove_table(policy->cpus);
  66 +       dev_pm_opp_remove_all_dynamic(cpu_dev);
  67
  68         return ret;
  69  }
  70 @@ -190,7 +190,7 @@ static int scpi_cpufreq_exit(struct cpuf
  71         clk_put(priv->clk);
  72         dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
  73         kfree(priv);
  74 -       dev_pm_opp_cpumask_remove_table(policy->related_cpus);
  75 +       dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
  76
  77         return 0;
  78  }
  79 --- a/drivers/opp/core.c
  80 +++ b/drivers/opp/core.c
  81 @@ -881,11 +881,9 @@ void _opp_free(struct dev_pm_opp *opp)
  82         kfree(opp);
  83  }
  84
  85 -static void _opp_kref_release(struct kref *kref)
  86 +static void _opp_kref_release(struct dev_pm_opp *opp,
  87 +                             struct opp_table *opp_table)
  88  {
  89 -       struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);
  90 -       struct opp_table *opp_table = opp->opp_table;
  91 -
  92         /*
  93          * Notify the changes in the availability of the operable
  94          * frequency/voltage list.
  95 @@ -894,7 +892,22 @@ static void _opp_kref_release(struct kre
  96         opp_debug_remove_one(opp);
  97         list_del(&opp->node);
  98         kfree(opp);
  99 +}
 100 +
 101 +static void _opp_kref_release_unlocked(struct kref *kref)
 102 +{
 103 +       struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);
 104 +       struct opp_table *opp_table = opp->opp_table;
 105 +
 106 +       _opp_kref_release(opp, opp_table);
 107 +}
 108
 109 +static void _opp_kref_release_locked(struct kref *kref)
 110 +{
 111 +       struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);
 112 +       struct opp_table *opp_table = opp->opp_table;
 113 +
 114 +       _opp_kref_release(opp, opp_table);
 115         mutex_unlock(&opp_table->lock);
 116         dev_pm_opp_put_opp_table(opp_table);
 117  }
 118 @@ -906,10 +919,16 @@ void dev_pm_opp_get(struct dev_pm_opp *o
 119
 120  void dev_pm_opp_put(struct dev_pm_opp *opp)
 121  {
 122 -       kref_put_mutex(&opp->kref, _opp_kref_release, &opp->opp_table->lock);
 123 +       kref_put_mutex(&opp->kref, _opp_kref_release_locked,
 124 +                      &opp->opp_table->lock);
 125  }
 126  EXPORT_SYMBOL_GPL(dev_pm_opp_put);
 127
 128 +static void dev_pm_opp_put_unlocked(struct dev_pm_opp *opp)
 129 +{
 130 +       kref_put(&opp->kref, _opp_kref_release_unlocked);
 131 +}
 132 +
 133  /**
 134   * dev_pm_opp_remove()  - Remove an OPP from OPP table
 135   * @dev:       device for which we do this operation
 136 @@ -949,6 +968,40 @@ void dev_pm_opp_remove(struct device *de
 137  }
 138  EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
 139
 140 +/**
 141 + * dev_pm_opp_remove_all_dynamic() - Remove all dynamically created OPPs
 142 + * @dev:       device for which we do this operation
 143 + *
 144 + * This function removes all dynamically created OPPs from the opp table.
 145 + */
 146 +void dev_pm_opp_remove_all_dynamic(struct device *dev)
 147 +{
 148 +       struct opp_table *opp_table;
 149 +       struct dev_pm_opp *opp, *temp;
 150 +       int count = 0;
 151 +
 152 +       opp_table = _find_opp_table(dev);
 153 +       if (IS_ERR(opp_table))
 154 +               return;
 155 +
 156 +       mutex_lock(&opp_table->lock);
 157 +       list_for_each_entry_safe(opp, temp, &opp_table->opp_list, node) {
 158 +               if (opp->dynamic) {
 159 +                       dev_pm_opp_put_unlocked(opp);
 160 +                       count++;
 161 +               }
 162 +       }
 163 +       mutex_unlock(&opp_table->lock);
 164 +
 165 +       /* Drop the references taken by dev_pm_opp_add() */
 166 +       while (count--)
 167 +               dev_pm_opp_put_opp_table(opp_table);
 168 +
 169 +       /* Drop the reference taken by _find_opp_table() */
 170 +       dev_pm_opp_put_opp_table(opp_table);
 171 +}
 172 +EXPORT_SYMBOL_GPL(dev_pm_opp_remove_all_dynamic);
 173 +
 174  struct dev_pm_opp *_opp_allocate(struct opp_table *table)
 175  {
 176         struct dev_pm_opp *opp;
 177 --- a/include/linux/pm_opp.h
 178 +++ b/include/linux/pm_opp.h
 179 @@ -107,6 +107,7 @@ void dev_pm_opp_put(struct dev_pm_opp *o
 180  int dev_pm_opp_add(struct device *dev, unsigned long freq,
 181                    unsigned long u_volt);
 182  void dev_pm_opp_remove(struct device *dev, unsigned long freq);
 183 +void dev_pm_opp_remove_all_dynamic(struct device *dev);
 184
 185  int dev_pm_opp_enable(struct device *dev, unsigned long freq);
 186
 187 @@ -208,6 +209,10 @@ static inline void dev_pm_opp_remove(str
 188  {
 189  }
 190
 191 +static inline void dev_pm_opp_remove_all_dynamic(struct device *dev)
 192 +{
 193 +}
 194 +
 195  static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq)
 196  {
 197         return 0;