PM / OPP: Update OPP users to put reference
authorViresh Kumar <viresh.kumar@linaro.org>
Mon, 23 Jan 2017 04:41:47 +0000 (10:11 +0530)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Mon, 30 Jan 2017 08:22:21 +0000 (09:22 +0100)
This patch updates dev_pm_opp_find_freq_*() routines to get a reference
to the OPPs returned by them.

Also updates the users of dev_pm_opp_find_freq_*() routines to call
dev_pm_opp_put() after they are done using the OPPs.

As it is guaranteed the that OPPs wouldn't get freed while being used,
the RCU read side locking present with the users isn't required anymore.
Drop it as well.

This patch also updates all users of devfreq_recommended_opp() which was
returning an OPP received from the OPP core.

Note that some of the OPP core routines have gained
rcu_read_{lock|unlock}() calls, as those still use RCU specific APIs
within them.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> [Devfreq]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
15 files changed:
arch/arm/mach-omap2/pm.c
drivers/base/power/opp/core.c
drivers/base/power/opp/cpu.c
drivers/clk/tegra/clk-dfll.c
drivers/cpufreq/exynos5440-cpufreq.c
drivers/cpufreq/imx6q-cpufreq.c
drivers/cpufreq/mt8173-cpufreq.c
drivers/cpufreq/omap-cpufreq.c
drivers/devfreq/devfreq.c
drivers/devfreq/exynos-bus.c
drivers/devfreq/governor_passive.c
drivers/devfreq/rk3399_dmc.c
drivers/devfreq/tegra-devfreq.c
drivers/thermal/cpu_cooling.c
drivers/thermal/devfreq_cooling.c

index 76b0454ddc4994220c2e6a2680ab596824caf7f6..0598630c17786242d20277fe59e9bbdb9cc9e928 100644 (file)
@@ -130,17 +130,16 @@ static int __init omap2_set_init_voltage(char *vdd_name, char *clk_name,
        freq = clk_get_rate(clk);
        clk_put(clk);
 
-       rcu_read_lock();
        opp = dev_pm_opp_find_freq_ceil(dev, &freq);
        if (IS_ERR(opp)) {
-               rcu_read_unlock();
                pr_err("%s: unable to find boot up OPP for vdd_%s\n",
                        __func__, vdd_name);
                goto exit;
        }
 
        bootup_volt = dev_pm_opp_get_voltage(opp);
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
+
        if (!bootup_volt) {
                pr_err("%s: unable to find voltage corresponding to the bootup OPP for vdd_%s\n",
                       __func__, vdd_name);
index 9870ee54d708cb2fa750a6bbb93b9ca51af44d57..a6efa818029a992a248a75927551fbb950684571 100644 (file)
@@ -40,6 +40,8 @@ do {                                                                  \
                         "opp_table_lock protection");                  \
 } while (0)
 
+static void dev_pm_opp_get(struct dev_pm_opp *opp);
+
 static struct opp_device *_find_opp_dev(const struct device *dev,
                                        struct opp_table *opp_table)
 {
@@ -94,21 +96,13 @@ struct opp_table *_find_opp_table(struct device *dev)
  * return 0
  *
  * This is useful only for devices with single power supply.
- *
- * Locking: This function must be called under rcu_read_lock(). opp is a rcu
- * protected pointer. This means that opp which could have been fetched by
- * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
- * under RCU lock. The pointer returned by the opp_find_freq family must be
- * used in the same section as the usage of this function with the pointer
- * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
- * pointer.
  */
 unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 {
        struct dev_pm_opp *tmp_opp;
        unsigned long v = 0;
 
-       opp_rcu_lockdep_assert();
+       rcu_read_lock();
 
        tmp_opp = rcu_dereference(opp);
        if (IS_ERR_OR_NULL(tmp_opp))
@@ -116,6 +110,7 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
        else
                v = tmp_opp->supplies[0].u_volt;
 
+       rcu_read_unlock();
        return v;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
@@ -126,21 +121,13 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
  *
  * Return: frequency in hertz corresponding to the opp, else
  * return 0
- *
- * Locking: This function must be called under rcu_read_lock(). opp is a rcu
- * protected pointer. This means that opp which could have been fetched by
- * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
- * under RCU lock. The pointer returned by the opp_find_freq family must be
- * used in the same section as the usage of this function with the pointer
- * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
- * pointer.
  */
 unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
 {
        struct dev_pm_opp *tmp_opp;
        unsigned long f = 0;
 
-       opp_rcu_lockdep_assert();
+       rcu_read_lock();
 
        tmp_opp = rcu_dereference(opp);
        if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
@@ -148,6 +135,7 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
        else
                f = tmp_opp->rate;
 
+       rcu_read_unlock();
        return f;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
@@ -161,20 +149,13 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
  * quickly. Running on them for longer times may overheat the chip.
  *
  * Return: true if opp is turbo opp, else false.
- *
- * Locking: This function must be called under rcu_read_lock(). opp is a rcu
- * protected pointer. This means that opp which could have been fetched by
- * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
- * under RCU lock. The pointer returned by the opp_find_freq family must be
- * used in the same section as the usage of this function with the pointer
- * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
- * pointer.
  */
 bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
 {
        struct dev_pm_opp *tmp_opp;
+       bool turbo;
 
-       opp_rcu_lockdep_assert();
+       rcu_read_lock();
 
        tmp_opp = rcu_dereference(opp);
        if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) {
@@ -182,7 +163,10 @@ bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
                return false;
        }
 
-       return tmp_opp->turbo;
+       turbo = tmp_opp->turbo;
+
+       rcu_read_unlock();
+       return turbo;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);
 
@@ -410,11 +394,8 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
  * This provides a mechanism to enable an opp which is not available currently
  * or the opposite as well.
  *
- * Locking: This function must be called under rcu_read_lock(). opp is a rcu
- * protected pointer. The reason for the same is that the opp pointer which is
- * returned will remain valid for use with opp_get_{voltage, freq} only while
- * under the locked area. The pointer returned must be used prior to unlocking
- * with rcu_read_unlock() to maintain the integrity of the pointer.
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
  */
 struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
                                              unsigned long freq,
@@ -423,13 +404,14 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
        struct opp_table *opp_table;
        struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
-       opp_rcu_lockdep_assert();
+       rcu_read_lock();
 
        opp_table = _find_opp_table(dev);
        if (IS_ERR(opp_table)) {
                int r = PTR_ERR(opp_table);
 
                dev_err(dev, "%s: OPP table not found (%d)\n", __func__, r);
+               rcu_read_unlock();
                return ERR_PTR(r);
        }
 
@@ -437,10 +419,15 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
                if (temp_opp->available == available &&
                                temp_opp->rate == freq) {
                        opp = temp_opp;
+
+                       /* Increment the reference count of OPP */
+                       dev_pm_opp_get(opp);
                        break;
                }
        }
 
+       rcu_read_unlock();
+
        return opp;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
@@ -454,6 +441,9 @@ static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
                if (temp_opp->available && temp_opp->rate >= *freq) {
                        opp = temp_opp;
                        *freq = opp->rate;
+
+                       /* Increment the reference count of OPP */
+                       dev_pm_opp_get(opp);
                        break;
                }
        }
@@ -476,29 +466,33 @@ static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
  * ERANGE:     no match found for search
  * ENODEV:     if device not found in list of registered devices
  *
- * Locking: This function must be called under rcu_read_lock(). opp is a rcu
- * protected pointer. The reason for the same is that the opp pointer which is
- * returned will remain valid for use with opp_get_{voltage, freq} only while
- * under the locked area. The pointer returned must be used prior to unlocking
- * with rcu_read_unlock() to maintain the integrity of the pointer.
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
  */
 struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
                                             unsigned long *freq)
 {
        struct opp_table *opp_table;
-
-       opp_rcu_lockdep_assert();
+       struct dev_pm_opp *opp;
 
        if (!dev || !freq) {
                dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
                return ERR_PTR(-EINVAL);
        }
 
+       rcu_read_lock();
+
        opp_table = _find_opp_table(dev);
-       if (IS_ERR(opp_table))
+       if (IS_ERR(opp_table)) {
+               rcu_read_unlock();
                return ERR_CAST(opp_table);
+       }
+
+       opp = _find_freq_ceil(opp_table, freq);
 
-       return _find_freq_ceil(opp_table, freq);
+       rcu_read_unlock();
+
+       return opp;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
 
@@ -517,11 +511,8 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
  * ERANGE:     no match found for search
  * ENODEV:     if device not found in list of registered devices
  *
- * Locking: This function must be called under rcu_read_lock(). opp is a rcu
- * protected pointer. The reason for the same is that the opp pointer which is
- * returned will remain valid for use with opp_get_{voltage, freq} only while
- * under the locked area. The pointer returned must be used prior to unlocking
- * with rcu_read_unlock() to maintain the integrity of the pointer.
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
  */
 struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
                                              unsigned long *freq)
@@ -529,16 +520,18 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
        struct opp_table *opp_table;
        struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
-       opp_rcu_lockdep_assert();
-
        if (!dev || !freq) {
                dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
                return ERR_PTR(-EINVAL);
        }
 
+       rcu_read_lock();
+
        opp_table = _find_opp_table(dev);
-       if (IS_ERR(opp_table))
+       if (IS_ERR(opp_table)) {
+               rcu_read_unlock();
                return ERR_CAST(opp_table);
+       }
 
        list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
                if (temp_opp->available) {
@@ -549,6 +542,12 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
                                opp = temp_opp;
                }
        }
+
+       /* Increment the reference count of OPP */
+       if (!IS_ERR(opp))
+               dev_pm_opp_get(opp);
+       rcu_read_unlock();
+
        if (!IS_ERR(opp))
                *freq = opp->rate;
 
@@ -736,6 +735,8 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
                ret = PTR_ERR(opp);
                dev_err(dev, "%s: failed to find OPP for freq %lu (%d)\n",
                        __func__, freq, ret);
+               if (!IS_ERR(old_opp))
+                       dev_pm_opp_put(old_opp);
                rcu_read_unlock();
                return ret;
        }
@@ -747,6 +748,9 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 
        /* Only frequency scaling */
        if (!regulators) {
+               dev_pm_opp_put(opp);
+               if (!IS_ERR(old_opp))
+                       dev_pm_opp_put(old_opp);
                rcu_read_unlock();
                return _generic_set_opp_clk_only(dev, clk, old_freq, freq);
        }
@@ -772,6 +776,9 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
        data->new_opp.rate = freq;
        memcpy(data->new_opp.supplies, opp->supplies, size);
 
+       dev_pm_opp_put(opp);
+       if (!IS_ERR(old_opp))
+               dev_pm_opp_put(old_opp);
        rcu_read_unlock();
 
        return set_opp(data);
@@ -967,6 +974,11 @@ static void _opp_kref_release(struct kref *kref)
        dev_pm_opp_put_opp_table(opp_table);
 }
 
+static void dev_pm_opp_get(struct dev_pm_opp *opp)
+{
+       kref_get(&opp->kref);
+}
+
 void dev_pm_opp_put(struct dev_pm_opp *opp)
 {
        kref_put_mutex(&opp->kref, _opp_kref_release, &opp->opp_table->lock);
index 8c3434bdb26dee8c23a637798b18a3963666ee70..adef788862d5b1ef003105b523425dde9b7db3a9 100644 (file)
  *
  * WARNING: It is  important for the callers to ensure refreshing their copy of
  * the table if any of the mentioned functions have been invoked in the interim.
- *
- * Locking: The internal opp_table and opp structures are RCU protected.
- * Since we just use the regular accessor functions to access the internal data
- * structures, we use RCU read lock inside this function. As a result, users of
- * this function DONOT need to use explicit locks for invoking.
  */
 int dev_pm_opp_init_cpufreq_table(struct device *dev,
                                  struct cpufreq_frequency_table **table)
@@ -56,19 +51,13 @@ int dev_pm_opp_init_cpufreq_table(struct device *dev,
        int i, max_opps, ret = 0;
        unsigned long rate;
 
-       rcu_read_lock();
-
        max_opps = dev_pm_opp_get_opp_count(dev);
-       if (max_opps <= 0) {
-               ret = max_opps ? max_opps : -ENODATA;
-               goto out;
-       }
+       if (max_opps <= 0)
+               return max_opps ? max_opps : -ENODATA;
 
        freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
-       if (!freq_table) {
-               ret = -ENOMEM;
-               goto out;
-       }
+       if (!freq_table)
+               return -ENOMEM;
 
        for (i = 0, rate = 0; i < max_opps; i++, rate++) {
                /* find next rate */
@@ -83,6 +72,8 @@ int dev_pm_opp_init_cpufreq_table(struct device *dev,
                /* Is Boost/turbo opp ? */
                if (dev_pm_opp_is_turbo(opp))
                        freq_table[i].flags = CPUFREQ_BOOST_FREQ;
+
+               dev_pm_opp_put(opp);
        }
 
        freq_table[i].driver_data = i;
@@ -91,7 +82,6 @@ int dev_pm_opp_init_cpufreq_table(struct device *dev,
        *table = &freq_table[0];
 
 out:
-       rcu_read_unlock();
        if (ret)
                kfree(freq_table);
 
index f010562534ebe056bc67ed57bad8f9a48c9458ff..2c44aeb0b97c7b437fa79b2cdf82f8ee9df577b0 100644 (file)
@@ -633,16 +633,12 @@ static int find_lut_index_for_rate(struct tegra_dfll *td, unsigned long rate)
        struct dev_pm_opp *opp;
        int i, uv;
 
-       rcu_read_lock();
-
        opp = dev_pm_opp_find_freq_ceil(td->soc->dev, &rate);
-       if (IS_ERR(opp)) {
-               rcu_read_unlock();
+       if (IS_ERR(opp))
                return PTR_ERR(opp);
-       }
-       uv = dev_pm_opp_get_voltage(opp);
 
-       rcu_read_unlock();
+       uv = dev_pm_opp_get_voltage(opp);
+       dev_pm_opp_put(opp);
 
        for (i = 0; i < td->i2c_lut_size; i++) {
                if (regulator_list_voltage(td->vdd_reg, td->i2c_lut[i]) == uv)
@@ -1440,8 +1436,6 @@ static int dfll_build_i2c_lut(struct tegra_dfll *td)
        struct dev_pm_opp *opp;
        int lut;
 
-       rcu_read_lock();
-
        rate = ULONG_MAX;
        opp = dev_pm_opp_find_freq_floor(td->soc->dev, &rate);
        if (IS_ERR(opp)) {
@@ -1449,6 +1443,7 @@ static int dfll_build_i2c_lut(struct tegra_dfll *td)
                goto out;
        }
        v_max = dev_pm_opp_get_voltage(opp);
+       dev_pm_opp_put(opp);
 
        v = td->soc->cvb->min_millivolts * 1000;
        lut = find_vdd_map_entry_exact(td, v);
@@ -1465,6 +1460,8 @@ static int dfll_build_i2c_lut(struct tegra_dfll *td)
                if (v_opp <= td->soc->cvb->min_millivolts * 1000)
                        td->dvco_rate_min = dev_pm_opp_get_freq(opp);
 
+               dev_pm_opp_put(opp);
+
                for (;;) {
                        v += max(1, (v_max - v) / (MAX_DFLL_VOLTAGES - j));
                        if (v >= v_opp)
@@ -1496,8 +1493,6 @@ static int dfll_build_i2c_lut(struct tegra_dfll *td)
                ret = 0;
 
 out:
-       rcu_read_unlock();
-
        return ret;
 }
 
index c0f3373706f4f04cd6ec197cb0791c2b3b7765de..9180d34cc9fce09be6255559e8d85b03be5c35a6 100644 (file)
@@ -118,12 +118,10 @@ static int init_div_table(void)
        unsigned int tmp, clk_div, ema_div, freq, volt_id;
        struct dev_pm_opp *opp;
 
-       rcu_read_lock();
        cpufreq_for_each_entry(pos, freq_tbl) {
                opp = dev_pm_opp_find_freq_exact(dvfs_info->dev,
                                        pos->frequency * 1000, true);
                if (IS_ERR(opp)) {
-                       rcu_read_unlock();
                        dev_err(dvfs_info->dev,
                                "failed to find valid OPP for %u KHZ\n",
                                pos->frequency);
@@ -140,6 +138,7 @@ static int init_div_table(void)
 
                /* Calculate EMA */
                volt_id = dev_pm_opp_get_voltage(opp);
+
                volt_id = (MAX_VOLTAGE - volt_id) / VOLTAGE_STEP;
                if (volt_id < PMIC_HIGH_VOLT) {
                        ema_div = (CPUEMA_HIGH << P0_7_CPUEMA_SHIFT) |
@@ -157,9 +156,9 @@ static int init_div_table(void)
 
                __raw_writel(tmp, dvfs_info->base + XMU_PMU_P0_7 + 4 *
                                                (pos - freq_tbl));
+               dev_pm_opp_put(opp);
        }
 
-       rcu_read_unlock();
        return 0;
 }
 
index ef1fa8145419cd1d2aa277f3dd20c9645e698203..7719b02e04f50f433e52bf4764461d4df6c2017b 100644 (file)
@@ -53,16 +53,15 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
        freq_hz = new_freq * 1000;
        old_freq = clk_get_rate(arm_clk) / 1000;
 
-       rcu_read_lock();
        opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
        if (IS_ERR(opp)) {
-               rcu_read_unlock();
                dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
                return PTR_ERR(opp);
        }
 
        volt = dev_pm_opp_get_voltage(opp);
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
+
        volt_old = regulator_get_voltage(arm_reg);
 
        dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
@@ -321,14 +320,15 @@ soc_opp_out:
         * freq_table initialised from OPP is therefore sorted in the
         * same order.
         */
-       rcu_read_lock();
        opp = dev_pm_opp_find_freq_exact(cpu_dev,
                                  freq_table[0].frequency * 1000, true);
        min_volt = dev_pm_opp_get_voltage(opp);
+       dev_pm_opp_put(opp);
        opp = dev_pm_opp_find_freq_exact(cpu_dev,
                                  freq_table[--num].frequency * 1000, true);
        max_volt = dev_pm_opp_get_voltage(opp);
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
+
        ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt);
        if (ret > 0)
                transition_latency += ret * 1000;
index 643f43179df16c1a56efc2930d61f31c7d7a79db..ab25b1235a5eadc32cbc7cf904e11665e786f878 100644 (file)
@@ -232,16 +232,14 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
 
        freq_hz = freq_table[index].frequency * 1000;
 
-       rcu_read_lock();
        opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_hz);
        if (IS_ERR(opp)) {
-               rcu_read_unlock();
                pr_err("cpu%d: failed to find OPP for %ld\n",
                       policy->cpu, freq_hz);
                return PTR_ERR(opp);
        }
        vproc = dev_pm_opp_get_voltage(opp);
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
 
        /*
         * If the new voltage or the intermediate voltage is higher than the
@@ -411,16 +409,14 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
 
        /* Search a safe voltage for intermediate frequency. */
        rate = clk_get_rate(inter_clk);
-       rcu_read_lock();
        opp = dev_pm_opp_find_freq_ceil(cpu_dev, &rate);
        if (IS_ERR(opp)) {
-               rcu_read_unlock();
                pr_err("failed to get intermediate opp for cpu%d\n", cpu);
                ret = PTR_ERR(opp);
                goto out_free_opp_table;
        }
        info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
 
        info->cpu_dev = cpu_dev;
        info->proc_reg = proc_reg;
index 376e63ca94e840e5334ae4d803dc9a173a69ab15..71e81bbf031b22cdc0ca6a227102ffeb7f01271f 100644 (file)
@@ -63,16 +63,14 @@ static int omap_target(struct cpufreq_policy *policy, unsigned int index)
        freq = ret;
 
        if (mpu_reg) {
-               rcu_read_lock();
                opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
                if (IS_ERR(opp)) {
-                       rcu_read_unlock();
                        dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
                                __func__, new_freq);
                        return -EINVAL;
                }
                volt = dev_pm_opp_get_voltage(opp);
-               rcu_read_unlock();
+               dev_pm_opp_put(opp);
                tol = volt * OPP_TOLERANCE / 100;
                volt_old = regulator_get_voltage(mpu_reg);
        }
index a545c0fee6e165498ec29196d12a9921c43f887f..253525ea17afabef1b61c36d06969aa82a3dd7e9 100644 (file)
@@ -111,18 +111,16 @@ static void devfreq_set_freq_table(struct devfreq *devfreq)
                return;
        }
 
-       rcu_read_lock();
        for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
                opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
                if (IS_ERR(opp)) {
                        devm_kfree(devfreq->dev.parent, profile->freq_table);
                        profile->max_state = 0;
-                       rcu_read_unlock();
                        return;
                }
+               dev_pm_opp_put(opp);
                profile->freq_table[i] = freq;
        }
-       rcu_read_unlock();
 }
 
 /**
@@ -1112,17 +1110,16 @@ static ssize_t available_frequencies_show(struct device *d,
        ssize_t count = 0;
        unsigned long freq = 0;
 
-       rcu_read_lock();
        do {
                opp = dev_pm_opp_find_freq_ceil(dev, &freq);
                if (IS_ERR(opp))
                        break;
 
+               dev_pm_opp_put(opp);
                count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
                                   "%lu ", freq);
                freq++;
        } while (1);
-       rcu_read_unlock();
 
        /* Truncate the trailing space */
        if (count)
@@ -1224,11 +1221,8 @@ subsys_initcall(devfreq_init);
  * @freq:      The frequency given to target function
  * @flags:     Flags handed from devfreq framework.
  *
- * Locking: This function must be called under rcu_read_lock(). opp is a rcu
- * protected pointer. The reason for the same is that the opp pointer which is
- * returned will remain valid for use with opp_get_{voltage, freq} only while
- * under the locked area. The pointer returned must be used prior to unlocking
- * with rcu_read_unlock() to maintain the integrity of the pointer.
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
  */
 struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
                                           unsigned long *freq,
index 9af86f46fbec0fc0779e4cf211c16227b804510d..c6d850cddd9881ef73b2516476eb2c955a66a880 100644 (file)
@@ -103,18 +103,17 @@ static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
        int ret = 0;
 
        /* Get new opp-bus instance according to new bus clock */
-       rcu_read_lock();
        new_opp = devfreq_recommended_opp(dev, freq, flags);
        if (IS_ERR(new_opp)) {
                dev_err(dev, "failed to get recommended opp instance\n");
-               rcu_read_unlock();
                return PTR_ERR(new_opp);
        }
 
        new_freq = dev_pm_opp_get_freq(new_opp);
        new_volt = dev_pm_opp_get_voltage(new_opp);
+       dev_pm_opp_put(new_opp);
+
        old_freq = bus->curr_freq;
-       rcu_read_unlock();
 
        if (old_freq == new_freq)
                return 0;
@@ -214,17 +213,16 @@ static int exynos_bus_passive_target(struct device *dev, unsigned long *freq,
        int ret = 0;
 
        /* Get new opp-bus instance according to new bus clock */
-       rcu_read_lock();
        new_opp = devfreq_recommended_opp(dev, freq, flags);
        if (IS_ERR(new_opp)) {
                dev_err(dev, "failed to get recommended opp instance\n");
-               rcu_read_unlock();
                return PTR_ERR(new_opp);
        }
 
        new_freq = dev_pm_opp_get_freq(new_opp);
+       dev_pm_opp_put(new_opp);
+
        old_freq = bus->curr_freq;
-       rcu_read_unlock();
 
        if (old_freq == new_freq)
                return 0;
@@ -358,16 +356,14 @@ static int exynos_bus_parse_of(struct device_node *np,
 
        rate = clk_get_rate(bus->clk);
 
-       rcu_read_lock();
        opp = devfreq_recommended_opp(dev, &rate, 0);
        if (IS_ERR(opp)) {
                dev_err(dev, "failed to find dev_pm_opp\n");
-               rcu_read_unlock();
                ret = PTR_ERR(opp);
                goto err_opp;
        }
        bus->curr_freq = dev_pm_opp_get_freq(opp);
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
 
        return 0;
 
index 9ef46e2592c45616cb59471c7cb2698155b56b7e..bd452236dba438e487a608835effa9f4aeccc80c 100644 (file)
@@ -59,14 +59,14 @@ static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
         * list of parent device. Because in this case, *freq is temporary
         * value which is decided by ondemand governor.
         */
-       rcu_read_lock();
        opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
-       rcu_read_unlock();
        if (IS_ERR(opp)) {
                ret = PTR_ERR(opp);
                goto out;
        }
 
+       dev_pm_opp_put(opp);
+
        /*
         * Get the OPP table's index of decided freqeuncy by governor
         * of parent device.
index 27d2f349b53c9ae7d8cd4db31681576e0dac8354..40a2499730fcb4cc635dfb9a0de2b9d50ea47869 100644 (file)
@@ -91,17 +91,13 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,
        unsigned long target_volt, target_rate;
        int err;
 
-       rcu_read_lock();
        opp = devfreq_recommended_opp(dev, freq, flags);
-       if (IS_ERR(opp)) {
-               rcu_read_unlock();
+       if (IS_ERR(opp))
                return PTR_ERR(opp);
-       }
 
        target_rate = dev_pm_opp_get_freq(opp);
        target_volt = dev_pm_opp_get_voltage(opp);
-
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
 
        if (dmcfreq->rate == target_rate)
                return 0;
@@ -422,15 +418,13 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
 
        data->rate = clk_get_rate(data->dmc_clk);
 
-       rcu_read_lock();
        opp = devfreq_recommended_opp(dev, &data->rate, 0);
-       if (IS_ERR(opp)) {
-               rcu_read_unlock();
+       if (IS_ERR(opp))
                return PTR_ERR(opp);
-       }
+
        data->rate = dev_pm_opp_get_freq(opp);
        data->volt = dev_pm_opp_get_voltage(opp);
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
 
        rk3399_devfreq_dmc_profile.initial_freq = data->rate;
 
index fe9dce0245bf0c7d32b2c8eb3590e7f73651ae6d..214fff96fa4a6c23d92b71eb1528348e2025afb8 100644 (file)
@@ -487,15 +487,13 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
        struct dev_pm_opp *opp;
        unsigned long rate = *freq * KHZ;
 
-       rcu_read_lock();
        opp = devfreq_recommended_opp(dev, &rate, flags);
        if (IS_ERR(opp)) {
-               rcu_read_unlock();
                dev_err(dev, "Failed to find opp for %lu KHz\n", *freq);
                return PTR_ERR(opp);
        }
        rate = dev_pm_opp_get_freq(opp);
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
 
        clk_set_min_rate(tegra->emc_clock, rate);
        clk_set_rate(tegra->emc_clock, 0);
index 9ce0e9eef9230c725eb510692f47e794ece255e9..85fdbf762fa02ac4d70ed231a603afe23bb5013d 100644 (file)
@@ -297,8 +297,6 @@ static int build_dyn_power_table(struct cpufreq_cooling_device *cpufreq_device,
        if (!power_table)
                return -ENOMEM;
 
-       rcu_read_lock();
-
        for (freq = 0, i = 0;
             opp = dev_pm_opp_find_freq_ceil(dev, &freq), !IS_ERR(opp);
             freq++, i++) {
@@ -306,13 +304,13 @@ static int build_dyn_power_table(struct cpufreq_cooling_device *cpufreq_device,
                u64 power;
 
                if (i >= num_opps) {
-                       rcu_read_unlock();
                        ret = -EAGAIN;
                        goto free_power_table;
                }
 
                freq_mhz = freq / 1000000;
                voltage_mv = dev_pm_opp_get_voltage(opp) / 1000;
+               dev_pm_opp_put(opp);
 
                /*
                 * Do the multiplication with MHz and millivolt so as
@@ -328,8 +326,6 @@ static int build_dyn_power_table(struct cpufreq_cooling_device *cpufreq_device,
                power_table[i].power = power;
        }
 
-       rcu_read_unlock();
-
        if (i != num_opps) {
                ret = PTR_ERR(opp);
                goto free_power_table;
@@ -433,13 +429,10 @@ static int get_static_power(struct cpufreq_cooling_device *cpufreq_device,
                return 0;
        }
 
-       rcu_read_lock();
-
        opp = dev_pm_opp_find_freq_exact(cpufreq_device->cpu_dev, freq_hz,
                                         true);
        voltage = dev_pm_opp_get_voltage(opp);
-
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
 
        if (voltage == 0) {
                dev_warn_ratelimited(cpufreq_device->cpu_dev,
index 5a737fd5f1aa470104406ccfafbd3e50d03b9a03..ba7a5cd994dc9229351bd4ee057941afabcab8fc 100644 (file)
@@ -113,15 +113,15 @@ static int partition_enable_opps(struct devfreq_cooling_device *dfc,
                unsigned int freq = dfc->freq_table[i];
                bool want_enable = i >= cdev_state ? true : false;
 
-               rcu_read_lock();
                opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
-               rcu_read_unlock();
 
                if (PTR_ERR(opp) == -ERANGE)
                        continue;
                else if (IS_ERR(opp))
                        return PTR_ERR(opp);
 
+               dev_pm_opp_put(opp);
+
                if (want_enable)
                        ret = dev_pm_opp_enable(dev, freq);
                else
@@ -221,15 +221,12 @@ get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq)
        if (!dfc->power_ops->get_static_power)
                return 0;
 
-       rcu_read_lock();
-
        opp = dev_pm_opp_find_freq_exact(dev, freq, true);
        if (IS_ERR(opp) && (PTR_ERR(opp) == -ERANGE))
                opp = dev_pm_opp_find_freq_exact(dev, freq, false);
 
        voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
-
-       rcu_read_unlock();
+       dev_pm_opp_put(opp);
 
        if (voltage == 0) {
                dev_warn_ratelimited(dev,
@@ -412,18 +409,14 @@ static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc)
                unsigned long power_dyn, voltage;
                struct dev_pm_opp *opp;
 
-               rcu_read_lock();
-
                opp = dev_pm_opp_find_freq_floor(dev, &freq);
                if (IS_ERR(opp)) {
-                       rcu_read_unlock();
                        ret = PTR_ERR(opp);
                        goto free_tables;
                }
 
                voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
-
-               rcu_read_unlock();
+               dev_pm_opp_put(opp);
 
                if (dfc->power_ops) {
                        power_dyn = get_dynamic_power(dfc, freq, voltage);