diff options
| author | Saravana Kannan <skannan@codeaurora.org> | 2014-02-28 07:38:57 +0400 |
|---|---|---|
| committer | MyungJoo Ham <myungjoo.ham@samsung.com> | 2014-03-21 06:16:30 +0400 |
| commit | e35d35a1c0b3a7317d77e03e686a4a205cdd4eed (patch) | |
| tree | 13bfac6f86fcc9fb5e40315d7e4a115f05e88bc5 | |
| parent | dcb99fd9b08cfe1afe426af4d8d3cbc429190f15 (diff) | |
| download | linux-e35d35a1c0b3a7317d77e03e686a4a205cdd4eed.tar.xz | |
PM / devfreq: Rewrite devfreq_update_status() to fix multiple bugs
The current devfreq_update_status() has the following bugs:
- If previous frequency doesn't have a valid level, it does an out of bounds
access into the trans_table and causes memory corruption.
- When the new frequency doesn't have a valid level, the time spent in the
new frequency is counted towards the next valid frequency switch instead of
being ignored.
- The time spent on the previous frequency is added to the new frequency's
stats instead of the previous frequency's stats.
This patch fixes all of this.
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
| -rw-r--r-- | drivers/devfreq/devfreq.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index a0b2f7e0eedb..2042ec3656ba 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -91,26 +91,35 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq) */ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) { - int lev, prev_lev; + int lev, prev_lev, ret = 0; unsigned long cur_time; - lev = devfreq_get_freq_level(devfreq, freq); - if (lev < 0) - return lev; - cur_time = jiffies; - devfreq->time_in_state[lev] += + + prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); + if (prev_lev < 0) { + ret = prev_lev; + goto out; + } + + devfreq->time_in_state[prev_lev] += cur_time - devfreq->last_stat_updated; - if (freq != devfreq->previous_freq) { - prev_lev = devfreq_get_freq_level(devfreq, - devfreq->previous_freq); + + lev = devfreq_get_freq_level(devfreq, freq); + if (lev < 0) { + ret = lev; + goto out; + } + + if (lev != prev_lev) { devfreq->trans_table[(prev_lev * devfreq->profile->max_state) + lev]++; devfreq->total_trans++; } - devfreq->last_stat_updated = cur_time; - return 0; +out: + devfreq->last_stat_updated = cur_time; + return ret; } /** |