* [PATCH v5] PM / devfreq: Restart previous governor if new governor fails to start @ 2019-03-11 10:06 Sibi Sankar [not found] ` <CGME20190311100759epcas5p41fc634cd67a99b39cd25c4129e489c4c@epcms1p2> 0 siblings, 1 reply; 3+ messages in thread From: Sibi Sankar @ 2019-03-11 10:06 UTC (permalink / raw) To: myungjoo.ham, kyungmin.park Cc: cw00.choi, linux-pm, linux-kernel, linux-arm-msm-owner, Saravana Kannan, Sibi Sankar From: Saravana Kannan <skannan@codeaurora.org> If the new governor fails to start, switch back to old governor so that the devfreq state is not left in some weird limbo. [Mjungjoo: assume fatal on revert failure and set df->governor to NULL] Signed-off-by: Sibi Sankar <sibis@codeaurora.org> Signed-off-by: Saravana Kannan <skannan@codeaurora.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> --- V5: * assume fatal on revert failure and set df->governor to NULL V4: * Removed prev_governor check. V3: * Fix NULL deref for real this time. * Addressed some style preferences. V2: * Fixed typo in commit text * Fixed potential NULL deref drivers/devfreq/devfreq.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 428a1de81008..37490235ec34 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -1124,7 +1124,7 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, struct devfreq *df = to_devfreq(dev); int ret; char str_governor[DEVFREQ_NAME_LEN + 1]; - struct devfreq_governor *governor; + const struct devfreq_governor *governor, *prev_governor; ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor); if (ret != 1) @@ -1153,12 +1153,24 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr, goto out; } } + prev_governor = df->governor; df->governor = governor; strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN); ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL); - if (ret) + if (ret) { dev_warn(dev, "%s: Governor %s not started(%d)\n", __func__, df->governor->name, ret); + df->governor = prev_governor; + strncpy(df->governor_name, prev_governor->name, + DEVFREQ_NAME_LEN); + ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL); + if (ret) { + dev_warn(dev, + "%s: reverting to Governor %s failed (%d)\n", + __func__, df->governor_name, ret); + df->governor = NULL; + } + } out: mutex_unlock(&devfreq_list_lock); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project ^ permalink raw reply related [flat|nested] 3+ messages in thread
[parent not found: <CGME20190311100759epcas5p41fc634cd67a99b39cd25c4129e489c4c@epcms1p2>]
* RE: [PATCH v5] PM / devfreq: Restart previous governor if new governor fails to start [not found] ` <CGME20190311100759epcas5p41fc634cd67a99b39cd25c4129e489c4c@epcms1p2> @ 2019-03-12 7:17 ` MyungJoo Ham 2019-03-13 6:01 ` Sibi Sankar 0 siblings, 1 reply; 3+ messages in thread From: MyungJoo Ham @ 2019-03-12 7:17 UTC (permalink / raw) To: Chanwoo Choi, Sibi Sankar Cc: Kyungmin Park, linux-pm, linux-kernel, linux-arm-msm-owner, Saravana Kannan >From: Saravana Kannan <skannan@codeaurora.org> > >If the new governor fails to start, switch back to old governor so that the >devfreq state is not left in some weird limbo. > >[Mjungjoo: assume fatal on revert failure and set df->governor to NULL] >Signed-off-by: Sibi Sankar <sibis@codeaurora.org> >Signed-off-by: Saravana Kannan <skannan@codeaurora.org> >Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> I'll modify WARN->ERROR for the case when it's fatal: >+ if (ret) { >+ dev_warn(dev, >+ "%s: reverting to Governor %s failed (%d)\n", >+ __func__, df->governor_name, ret); >+ df->governor = NULL; >+ } Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> >--- >V5: >* assume fatal on revert failure and set df->governor to NULL > >V4: >* Removed prev_governor check. > >V3: >* Fix NULL deref for real this time. >* Addressed some style preferences. > >V2: >* Fixed typo in commit text >* Fixed potential NULL deref > > drivers/devfreq/devfreq.c | 16 ++++++++++++++-- > 1 file changed, 14 insertions(+), 2 deletions(-) > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v5] PM / devfreq: Restart previous governor if new governor fails to start 2019-03-12 7:17 ` MyungJoo Ham @ 2019-03-13 6:01 ` Sibi Sankar 0 siblings, 0 replies; 3+ messages in thread From: Sibi Sankar @ 2019-03-13 6:01 UTC (permalink / raw) To: myungjoo.ham Cc: Chanwoo Choi, Kyungmin Park, linux-pm, linux-kernel, linux-arm-msm-owner, Saravana Kannan On 2019-03-12 12:47, MyungJoo Ham wrote: >> From: Saravana Kannan <skannan@codeaurora.org> >> >> If the new governor fails to start, switch back to old governor so >> that the >> devfreq state is not left in some weird limbo. >> >> [Mjungjoo: assume fatal on revert failure and set df->governor to >> NULL] >> Signed-off-by: Sibi Sankar <sibis@codeaurora.org> >> Signed-off-by: Saravana Kannan <skannan@codeaurora.org> >> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> > > I'll modify WARN->ERROR for the case when it's fatal: Sure, thanks. > >> + if (ret) { >> + dev_warn(dev, >> + "%s: reverting to Governor %s failed (%d)\n", >> + __func__, df->governor_name, ret); >> + df->governor = NULL; >> + } > > Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> > > >> --- >> V5: >> * assume fatal on revert failure and set df->governor to NULL >> >> V4: >> * Removed prev_governor check. >> >> V3: >> * Fix NULL deref for real this time. >> * Addressed some style preferences. >> >> V2: >> * Fixed typo in commit text >> * Fixed potential NULL deref >> >> drivers/devfreq/devfreq.c | 16 ++++++++++++++-- >> 1 file changed, 14 insertions(+), 2 deletions(-) >> -- -- Sibi Sankar -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project. ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-03-13 6:01 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-03-11 10:06 [PATCH v5] PM / devfreq: Restart previous governor if new governor fails to start Sibi Sankar [not found] ` <CGME20190311100759epcas5p41fc634cd67a99b39cd25c4129e489c4c@epcms1p2> 2019-03-12 7:17 ` MyungJoo Ham 2019-03-13 6:01 ` Sibi Sankar
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).