The vast majority of code uses df->previous_freq to get the current frequency of the devfreq device, not the previous one. Rename the struct field to reflect this.
Add a comment to devfreq_update_stats() to make clear that df->cur_freq must only be updated after calling this function in the context of a frequency transition. Signed-off-by: Matthias Kaehlcke <[email protected]> --- drivers/devfreq/devfreq.c | 28 ++++++++++++++++------------ drivers/devfreq/governor_passive.c | 6 +++--- drivers/devfreq/governor_userspace.c | 2 +- drivers/devfreq/tegra20-devfreq.c | 2 +- drivers/devfreq/tegra30-devfreq.c | 2 +- include/linux/devfreq.h | 4 ++-- include/trace/events/devfreq.h | 2 +- 7 files changed, 25 insertions(+), 21 deletions(-) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index fb4318d59aa9..bf42130bb4ec 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -154,6 +154,10 @@ static int set_freq_table(struct devfreq *devfreq) * devfreq_update_stats() - Update statistics of devfreq behavior * @devfreq: the devfreq instance * @freq: the update target frequency + * + * If the function is called in the context of a frequency transition + * it expects df->cur_freq to contain the value *before* the transition. + * The field must only be updated after calling devfreq_update_stats(). */ int devfreq_update_stats(struct devfreq *devfreq, unsigned long freq) { @@ -162,11 +166,11 @@ int devfreq_update_stats(struct devfreq *devfreq, unsigned long freq) cur_time = jiffies; - /* Immediately exit if previous_freq is not initialized yet. */ - if (!devfreq->previous_freq) + /* Immediately exit if cur_freq is not initialized yet. */ + if (!devfreq->cur_freq) goto out; - prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); + prev_lev = devfreq_get_freq_level(devfreq, devfreq->cur_freq); if (prev_lev < 0) { ret = prev_lev; goto out; @@ -295,7 +299,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, if (devfreq->profile->get_cur_freq) devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq); else - cur_freq = devfreq->previous_freq; + cur_freq = devfreq->cur_freq; freqs.old = cur_freq; freqs.new = new_freq; @@ -315,7 +319,7 @@ static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, dev_err(&devfreq->dev, "Couldn't update frequency transition information.\n"); - devfreq->previous_freq = new_freq; + devfreq->cur_freq = new_freq; if (devfreq->suspend_freq) devfreq->resume_freq = cur_freq; @@ -450,7 +454,7 @@ void devfreq_monitor_suspend(struct devfreq *devfreq) return; } - devfreq_update_stats(devfreq, devfreq->previous_freq); + devfreq_update_stats(devfreq, devfreq->cur_freq); devfreq->stop_polling = true; mutex_unlock(&devfreq->lock); cancel_delayed_work_sync(&devfreq->work); @@ -483,7 +487,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq) if (devfreq->profile->get_cur_freq && !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq)) - devfreq->previous_freq = freq; + devfreq->cur_freq = freq; out: mutex_unlock(&devfreq->lock); @@ -644,7 +648,7 @@ struct devfreq *devfreq_add_device(struct device *dev, devfreq->dev.release = devfreq_dev_release; devfreq->profile = profile; strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN); - devfreq->previous_freq = profile->initial_freq; + devfreq->cur_freq = profile->initial_freq; devfreq->last_status.current_frequency = profile->initial_freq; devfreq->data = data; devfreq->nb.notifier_call = devfreq_notifier_call; @@ -1235,14 +1239,14 @@ static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr, !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq)) return sprintf(buf, "%lu\n", freq); - return sprintf(buf, "%lu\n", devfreq->previous_freq); + return sprintf(buf, "%lu\n", devfreq->cur_freq); } static DEVICE_ATTR_RO(cur_freq); static ssize_t target_freq_show(struct device *dev, struct device_attribute *attr, char *buf) { - return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq); + return sprintf(buf, "%lu\n", to_devfreq(dev)->cur_freq); } static DEVICE_ATTR_RO(target_freq); @@ -1398,7 +1402,7 @@ static ssize_t trans_stat_show(struct device *dev, unsigned int max_state = devfreq->profile->max_state; if (!devfreq->stop_polling && - devfreq_update_stats(devfreq, devfreq->previous_freq)) + devfreq_update_stats(devfreq, devfreq->cur_freq)) return 0; if (max_state == 0) return sprintf(buf, "Not Supported.\n"); @@ -1413,7 +1417,7 @@ static ssize_t trans_stat_show(struct device *dev, for (i = 0; i < max_state; i++) { if (devfreq->profile->freq_table[i] - == devfreq->previous_freq) { + == devfreq->cur_freq) { len += sprintf(buf + len, "*"); } else { len += sprintf(buf + len, " "); diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c index 1c746b96d3db..2d818eaceb39 100644 --- a/drivers/devfreq/governor_passive.c +++ b/drivers/devfreq/governor_passive.c @@ -114,7 +114,7 @@ static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq) dev_err(&devfreq->dev, "Couldn't update frequency transition information.\n"); - devfreq->previous_freq = freq; + devfreq->cur_freq = freq; out: mutex_unlock(&devfreq->lock); @@ -134,11 +134,11 @@ static int devfreq_passive_notifier_call(struct notifier_block *nb, switch (event) { case DEVFREQ_PRECHANGE: - if (parent->previous_freq > freq) + if (parent->cur_freq > freq) update_devfreq_passive(devfreq, freq); break; case DEVFREQ_POSTCHANGE: - if (parent->previous_freq < freq) + if (parent->cur_freq < freq) update_devfreq_passive(devfreq, freq); break; } diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c index af94942fcf95..566b8d1f0c17 100644 --- a/drivers/devfreq/governor_userspace.c +++ b/drivers/devfreq/governor_userspace.c @@ -26,7 +26,7 @@ static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq) if (data->valid) *freq = data->user_frequency; else - *freq = df->previous_freq; /* No user freq specified yet */ + *freq = df->cur_freq; /* No user freq specified yet */ return 0; } diff --git a/drivers/devfreq/tegra20-devfreq.c b/drivers/devfreq/tegra20-devfreq.c index ff82bac9ee4e..f99bd6557df5 100644 --- a/drivers/devfreq/tegra20-devfreq.c +++ b/drivers/devfreq/tegra20-devfreq.c @@ -61,7 +61,7 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq, return 0; restore_min_rate: - clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq); + clk_set_min_rate(tegra->emc_clock, devfreq->cur_freq); return err; } diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c index 536273a811fe..7b3bf7a0b15f 100644 --- a/drivers/devfreq/tegra30-devfreq.c +++ b/drivers/devfreq/tegra30-devfreq.c @@ -474,7 +474,7 @@ static int tegra_devfreq_target(struct device *dev, unsigned long *freq, return 0; restore_min_rate: - clk_set_min_rate(tegra->emc_clock, devfreq->previous_freq); + clk_set_min_rate(tegra->emc_clock, devfreq->cur_freq); return err; } diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index 2bae9ed3c783..21d0108df4c5 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -120,7 +120,7 @@ struct devfreq_dev_profile { * reevaluate operable frequencies. Devfreq users may use * devfreq.nb to the corresponding register notifier call chain. * @work: delayed work for load monitoring. - * @previous_freq: previously configured frequency value. + * @cur_freq: the current frequency. * @data: Private data of the governor. The devfreq framework does not * touch this. * @min_freq: Limit minimum frequency requested by user (0: none) @@ -156,7 +156,7 @@ struct devfreq { struct notifier_block nb; struct delayed_work work; - unsigned long previous_freq; + unsigned long cur_freq; struct devfreq_dev_status last_status; void *data; /* private data for governors */ diff --git a/include/trace/events/devfreq.h b/include/trace/events/devfreq.h index cf5b8772175d..916cfaed5489 100644 --- a/include/trace/events/devfreq.h +++ b/include/trace/events/devfreq.h @@ -22,7 +22,7 @@ TRACE_EVENT(devfreq_monitor, ), TP_fast_assign( - __entry->freq = devfreq->previous_freq; + __entry->freq = devfreq->cur_freq; __entry->busy_time = devfreq->last_status.busy_time; __entry->total_time = devfreq->last_status.total_time; __entry->polling_ms = devfreq->profile->polling_ms; -- 2.23.0.444.g18eeb5a265-goog
