| Message ID | 20200623204606.13045-1-mike.leach@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: etmv4: Fix CPU power management setup in probe() function. | expand |
Hi Mike, On Tue, Jun 23, 2020 at 09:46:06PM +0100, Mike Leach wrote: > The current probe() function calls a pair of cpuhp_xxx API functions to > setup CPU hotplug handling. The hotplug lock is held for the duration of > the two calls and other CPU related code using cpus_read_lock() / > cpus_read_unlock() calls. > > The problem is that on error states, goto: statements bypass the > cpus_read_unlock() call. This code has increased in complexity as the > driver has developed. > > This patch introduces a pair of helper functions etm4_pm_setup() and > etm4_pm_clear() which correct the issues above and group the PM code a > little better. > > The two functions etm4_cpu_pm_register() and etm4_cpu_pm_unregister() are > dropped as these call cpu_pm_register_notifier() / ..unregister_notifier() > dependent on CONFIG_CPU_PM - but this define is used to nop these functions > out in the pm headers - so the wrapper functions are superfluous. > > Fixes: f188b5e76aae ("coresight: etm4x: Save/restore state across CPU low power states") > Fixes: e9f5d63f84fe ("hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked()") > Fixes: 58eb457be028 ("etm4x: Convert to hotplug state machine") > > Signed-off-by: Mike Leach <mike.leach@linaro.org> > --- > drivers/hwtracing/coresight/coresight-etm4x.c | 79 ++++++++++++------- > 1 file changed, 51 insertions(+), 28 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c > index 919b76fa49c4..4dd59de440de 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x.c > @@ -1407,18 +1407,56 @@ static struct notifier_block etm4_cpu_pm_nb = { > .notifier_call = etm4_cpu_pm_notify, > }; > > -static int etm4_cpu_pm_register(void) > +/* Setup PM. Called with cpus locked. Deals with error conditions and counts */ > +static int etm4_pm_setup_cpuslocked(void) > { > - if (IS_ENABLED(CONFIG_CPU_PM)) > - return cpu_pm_register_notifier(&etm4_cpu_pm_nb); > + int ret; > > - return 0; > + if (etm4_count++) > + return 0; > + > + ret = cpu_pm_register_notifier(&etm4_cpu_pm_nb); > + if (ret) > + goto reduce_count; > + > + ret = cpuhp_setup_state_nocalls_cpuslocked( > + CPUHP_AP_ARM_CORESIGHT_STARTING, "arm/coresight4:starting", > + etm4_starting_cpu, etm4_dying_cpu); The 80 character limit per line has been relaxed to 100 in the 5.8 cycle. As such you can arrange CPUHP_AP_ARM_CORESIGHT_STARTING the same way you did below with CPUHP_AP_ONLINE_DYN without getting yelled at by checkpatch. > + > + if (ret) > + goto unregister_notifier; > + > + ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN, > + "arm/coresight4:online", > + etm4_online_cpu, NULL); > + > + /* HP dyn state ID returned in ret on success */ > + if (ret > 0) { > + hp_online = ret; > + return 0; > + } > + > + /* failed dyn state - remove others */ > + cpuhp_remove_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING); > + > +unregister_notifier: > + cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); > + > +reduce_count: > + --etm4_count; > + return ret; > } > > -static void etm4_cpu_pm_unregister(void) > +static void etm4_pm_clear(void) > { > - if (IS_ENABLED(CONFIG_CPU_PM)) > + if (--etm4_count == 0) { if (--etm4_count != 0) return; > cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); > + cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING); > + if (hp_online) { > + cpuhp_remove_state_nocalls(hp_online); > + hp_online = 0; > + } > + } > } > > static int etm4_probe(struct amba_device *adev, const struct amba_id *id) > @@ -1475,24 +1513,15 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) > etm4_init_arch_data, drvdata, 1)) > dev_err(dev, "ETM arch init failed\n"); > > - if (!etm4_count++) { > - cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING, > - "arm/coresight4:starting", > - etm4_starting_cpu, etm4_dying_cpu); > - ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN, > - "arm/coresight4:online", > - etm4_online_cpu, NULL); > - if (ret < 0) > - goto err_arch_supported; > - hp_online = ret; > + ret = etm4_pm_setup_cpuslocked(); > + cpus_read_unlock(); > > - ret = etm4_cpu_pm_register(); > - if (ret) > - goto err_arch_supported; > + /* etm4_pm_setup does its own cleanup - just exit on error here */ s/etm4_pm_setup/etm4_pm_setup_cpuslocked() Otherwise this is a good cleanup. Thanks, Mathieu > + if (ret) { > + etmdrvdata[drvdata->cpu] = NULL; > + return ret; > } > > - cpus_read_unlock(); > - > if (etm4_arch_supported(drvdata->arch) == false) { > ret = -EINVAL; > goto err_arch_supported; > @@ -1544,13 +1573,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) > > err_arch_supported: > etmdrvdata[drvdata->cpu] = NULL; > - if (--etm4_count == 0) { > - etm4_cpu_pm_unregister(); > - > - cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING); > - if (hp_online) > - cpuhp_remove_state_nocalls(hp_online); > - } > + etm4_pm_clear(); > return ret; > } > > -- > 2.17.1 >
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c index 919b76fa49c4..4dd59de440de 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.c +++ b/drivers/hwtracing/coresight/coresight-etm4x.c @@ -1407,18 +1407,56 @@ static struct notifier_block etm4_cpu_pm_nb = { .notifier_call = etm4_cpu_pm_notify, }; -static int etm4_cpu_pm_register(void) +/* Setup PM. Called with cpus locked. Deals with error conditions and counts */ +static int etm4_pm_setup_cpuslocked(void) { - if (IS_ENABLED(CONFIG_CPU_PM)) - return cpu_pm_register_notifier(&etm4_cpu_pm_nb); + int ret; - return 0; + if (etm4_count++) + return 0; + + ret = cpu_pm_register_notifier(&etm4_cpu_pm_nb); + if (ret) + goto reduce_count; + + ret = cpuhp_setup_state_nocalls_cpuslocked( + CPUHP_AP_ARM_CORESIGHT_STARTING, "arm/coresight4:starting", + etm4_starting_cpu, etm4_dying_cpu); + + if (ret) + goto unregister_notifier; + + ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN, + "arm/coresight4:online", + etm4_online_cpu, NULL); + + /* HP dyn state ID returned in ret on success */ + if (ret > 0) { + hp_online = ret; + return 0; + } + + /* failed dyn state - remove others */ + cpuhp_remove_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING); + +unregister_notifier: + cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); + +reduce_count: + --etm4_count; + return ret; } -static void etm4_cpu_pm_unregister(void) +static void etm4_pm_clear(void) { - if (IS_ENABLED(CONFIG_CPU_PM)) + if (--etm4_count == 0) { cpu_pm_unregister_notifier(&etm4_cpu_pm_nb); + cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING); + if (hp_online) { + cpuhp_remove_state_nocalls(hp_online); + hp_online = 0; + } + } } static int etm4_probe(struct amba_device *adev, const struct amba_id *id) @@ -1475,24 +1513,15 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) etm4_init_arch_data, drvdata, 1)) dev_err(dev, "ETM arch init failed\n"); - if (!etm4_count++) { - cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING, - "arm/coresight4:starting", - etm4_starting_cpu, etm4_dying_cpu); - ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN, - "arm/coresight4:online", - etm4_online_cpu, NULL); - if (ret < 0) - goto err_arch_supported; - hp_online = ret; + ret = etm4_pm_setup_cpuslocked(); + cpus_read_unlock(); - ret = etm4_cpu_pm_register(); - if (ret) - goto err_arch_supported; + /* etm4_pm_setup does its own cleanup - just exit on error here */ + if (ret) { + etmdrvdata[drvdata->cpu] = NULL; + return ret; } - cpus_read_unlock(); - if (etm4_arch_supported(drvdata->arch) == false) { ret = -EINVAL; goto err_arch_supported; @@ -1544,13 +1573,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) err_arch_supported: etmdrvdata[drvdata->cpu] = NULL; - if (--etm4_count == 0) { - etm4_cpu_pm_unregister(); - - cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING); - if (hp_online) - cpuhp_remove_state_nocalls(hp_online); - } + etm4_pm_clear(); return ret; }
The current probe() function calls a pair of cpuhp_xxx API functions to setup CPU hotplug handling. The hotplug lock is held for the duration of the two calls and other CPU related code using cpus_read_lock() / cpus_read_unlock() calls. The problem is that on error states, goto: statements bypass the cpus_read_unlock() call. This code has increased in complexity as the driver has developed. This patch introduces a pair of helper functions etm4_pm_setup() and etm4_pm_clear() which correct the issues above and group the PM code a little better. The two functions etm4_cpu_pm_register() and etm4_cpu_pm_unregister() are dropped as these call cpu_pm_register_notifier() / ..unregister_notifier() dependent on CONFIG_CPU_PM - but this define is used to nop these functions out in the pm headers - so the wrapper functions are superfluous. Fixes: f188b5e76aae ("coresight: etm4x: Save/restore state across CPU low power states") Fixes: e9f5d63f84fe ("hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_cpuslocked()") Fixes: 58eb457be028 ("etm4x: Convert to hotplug state machine") Signed-off-by: Mike Leach <mike.leach@linaro.org> --- drivers/hwtracing/coresight/coresight-etm4x.c | 79 ++++++++++++------- 1 file changed, 51 insertions(+), 28 deletions(-)