From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nishanth Menon Subject: Re: [PATCH V5] PM/OPP: discard duplicate OPPs Date: Tue, 20 May 2014 10:19:02 -0500 Message-ID: <537B7266.1050301@ti.com> References: <7cb6e0e039e0935e37c81d0f23d26b0b81ad8cda.1400597170.git.viresh.kumar@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from devils.ext.ti.com ([198.47.26.153]:52544 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751760AbaETPTX (ORCPT ); Tue, 20 May 2014 11:19:23 -0400 In-Reply-To: <7cb6e0e039e0935e37c81d0f23d26b0b81ad8cda.1400597170.git.viresh.kumar@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Viresh Kumar , rjw@rjwysocki.net Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, arvind.chauhan@arm.com, inderpal.s@samsung.com, chander.kashyap@linaro.org, pavel@ucw.cz, len.brown@intel.com, Chander Kashyap On 05/20/2014 09:53 AM, Viresh Kumar wrote: > From: Chander Kashyap > > We don't have any protection against addition of duplicate OPPs currently and > in case some code tries to add them it will end up corrupting OPP tables. > > There can be many combinations in which we may end up trying duplicate OPPs: > - both freq and volt are same, but earlier OPP may or may not be active. > - only freq is same and volt is different. > > This patch tries to implement below logic for these cases: > > Return 0 if new OPP was duplicate of existing one (i.e. same freq and volt) and > return -EEXIST if new OPP had same freq but different volt as of an existing OPP > OR if both freq/volt were same but earlier OPP was disabled. > > Signed-off-by: Chander Kashyap > Signed-off-by: Inderpal Singh > Signed-off-by: Viresh Kumar > --- > V4->V5: > - Mention Return values under 'Return:' clause of doc style comment. > - s/pr_warn/dev_warn > - s/linrao/linaro in my email id :( > > drivers/base/power/opp.c | 27 +++++++++++++++++++++++++-- > 1 file changed, 25 insertions(+), 2 deletions(-) > > diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c > index 2553867..6a06d43 100644 > --- a/drivers/base/power/opp.c > +++ b/drivers/base/power/opp.c > @@ -394,6 +394,13 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor); > * to keep the integrity of the internal data structures. Callers should ensure > * that this function is *NOT* called under RCU protection or in contexts where > * mutex cannot be locked. > + * > + * Returns: s/Returns:/Return:/ -> sorry for being a nitpick.. scripts/kernel-doc uses "Return:" in $section_return > + * 0: On success OR > + * Duplicate OPPs (both freq and volt are same) and opp->available > + * -EEXIST: Freq are same and volt are different OR > + * Duplicate OPPs (both freq and volt are same) and !opp->available > + * -ENOMEM: Memory allocation failure > */ > int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) > { > @@ -443,15 +450,31 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) > new_opp->u_volt = u_volt; > new_opp->available = true; > > - /* Insert new OPP in order of increasing frequency */ > + /* > + * Insert new OPP in order of increasing frequency > + * and discard if already present > + */ > head = &dev_opp->opp_list; > list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) { > - if (new_opp->rate < opp->rate) > + if (new_opp->rate <= opp->rate) > break; > else > head = &opp->node; > } > > + /* Duplicate OPPs ? */ > + if (new_opp->rate == opp->rate) { > + int ret = (new_opp->u_volt == opp->u_volt) && opp->available ? > + 0 : -EEXIST; > + > + dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n", > + __func__, opp->rate, opp->u_volt, opp->available, > + new_opp->rate, new_opp->u_volt, new_opp->available); checkpatch --strict showed: --- /tmp/kernel-patch-verify.22670/ptest_check-start 2014-05-20 10:07:15.736147182 -0500 +++ /tmp/kernel-patch-verify.22670/ptest_check-end 2014-05-20 10:07:15.960149013 -0500 @@ -0,0 +1,6 @@ +CHECK: Alignment should match open parenthesis +#68: FILE: drivers/base/power/opp.c:471: ++ dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n", ++ __func__, opp->rate, opp->u_volt, opp->available, +If any of these errors are false positives, please report +them to the maintainer, see CHECKPATCH in MAINTAINERS. > + mutex_unlock(&dev_opp_list_lock); > + kfree(new_opp); > + return ret; > + } > + > list_add_rcu(&new_opp->node, head); > mutex_unlock(&dev_opp_list_lock); > > Other than these minor fixes, Acked-by: Nishanth Menon -- Regards, Nishanth Menon