On Wed, 23 Oct 2024 at 12:22, Sibi Sankar <quic_sibis@xxxxxxxxxxx> wrote: > > The domain attributes returned by the perf protocol can end up > reporting identical names across domains, resulting in debugfs > node creation failure. Fix this failure by ensuring that pm domains > get a unique name using ida in pm_genpd_init. > > Logs: [X1E reports 'NCC' for all its scmi perf domains] > debugfs: Directory 'NCC' with parent 'pm_genpd' already present! > debugfs: Directory 'NCC' with parent 'pm_genpd' already present! > > Reported-by: Johan Hovold <johan+linaro@xxxxxxxxxx> > Closes: https://lore.kernel.org/lkml/ZoQjAWse2YxwyRJv@xxxxxxxxxxxxxxxxxxxx/ > Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains") > Suggested-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > Signed-off-by: Sibi Sankar <quic_sibis@xxxxxxxxxxx> > --- > > v3: > * Update device names only when a name collision occurs [Dmitry/Ulf] > * Drop Johan's T-b from "fix debugfs node creation failure" > > drivers/pmdomain/core.c | 65 ++++++++++++++++++++++++++++++--------- > include/linux/pm_domain.h | 1 + > 2 files changed, 51 insertions(+), 15 deletions(-) > > diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c > index 76490f0bf1e2..756ed0975788 100644 > --- a/drivers/pmdomain/core.c > +++ b/drivers/pmdomain/core.c > @@ -7,6 +7,7 @@ > #define pr_fmt(fmt) "PM: " fmt > > #include <linux/delay.h> > +#include <linux/idr.h> > #include <linux/kernel.h> > #include <linux/io.h> > #include <linux/platform_device.h> > @@ -23,6 +24,9 @@ > #include <linux/cpu.h> > #include <linux/debugfs.h> > > +/* Provides a unique ID for each genpd device */ > +static DEFINE_IDA(genpd_ida); > + > #define GENPD_RETRY_MAX_MS 250 /* Approximate */ > > #define GENPD_DEV_CALLBACK(genpd, type, callback, dev) \ > @@ -189,7 +193,7 @@ static inline bool irq_safe_dev_in_sleep_domain(struct device *dev, > > if (ret) > dev_warn_once(dev, "PM domain %s will not be powered off\n", > - genpd->name); > + dev_name(&genpd->dev)); > > return ret; > } > @@ -274,7 +278,7 @@ static void genpd_debug_remove(struct generic_pm_domain *genpd) > if (!genpd_debugfs_dir) > return; > > - debugfs_lookup_and_remove(genpd->name, genpd_debugfs_dir); > + debugfs_lookup_and_remove(dev_name(&genpd->dev), genpd_debugfs_dir); > } > > static void genpd_update_accounting(struct generic_pm_domain *genpd) > @@ -731,7 +735,7 @@ static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed) > genpd->states[state_idx].power_on_latency_ns = elapsed_ns; > genpd->gd->max_off_time_changed = true; > pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n", > - genpd->name, "on", elapsed_ns); > + dev_name(&genpd->dev), "on", elapsed_ns); > > out: > raw_notifier_call_chain(&genpd->power_notifiers, GENPD_NOTIFY_ON, NULL); > @@ -782,7 +786,7 @@ static int _genpd_power_off(struct generic_pm_domain *genpd, bool timed) > genpd->states[state_idx].power_off_latency_ns = elapsed_ns; > genpd->gd->max_off_time_changed = true; > pr_debug("%s: Power-%s latency exceeded, new value %lld ns\n", > - genpd->name, "off", elapsed_ns); > + dev_name(&genpd->dev), "off", elapsed_ns); > > out: > raw_notifier_call_chain(&genpd->power_notifiers, GENPD_NOTIFY_OFF, > @@ -1941,7 +1945,7 @@ int dev_pm_genpd_add_notifier(struct device *dev, struct notifier_block *nb) > > if (ret) { > dev_warn(dev, "failed to add notifier for PM domain %s\n", > - genpd->name); > + dev_name(&genpd->dev)); > return ret; > } > > @@ -1988,7 +1992,7 @@ int dev_pm_genpd_remove_notifier(struct device *dev) > > if (ret) { > dev_warn(dev, "failed to remove notifier for PM domain %s\n", > - genpd->name); > + dev_name(&genpd->dev)); > return ret; > } > > @@ -2014,7 +2018,7 @@ static int genpd_add_subdomain(struct generic_pm_domain *genpd, > */ > if (!genpd_is_irq_safe(genpd) && genpd_is_irq_safe(subdomain)) { > WARN(1, "Parent %s of subdomain %s must be IRQ safe\n", > - genpd->name, subdomain->name); > + dev_name(&genpd->dev), subdomain->name); > return -EINVAL; > } > > @@ -2089,7 +2093,7 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd, > > if (!list_empty(&subdomain->parent_links) || subdomain->device_count) { > pr_warn("%s: unable to remove subdomain %s\n", > - genpd->name, subdomain->name); > + dev_name(&genpd->dev), subdomain->name); > ret = -EBUSY; > goto out; > } > @@ -2199,6 +2203,23 @@ static void genpd_lock_init(struct generic_pm_domain *genpd) > } > } > > +static bool genpd_name_present(const char *name) > +{ > + bool ret = false; > + const struct generic_pm_domain *gpd; > + > + mutex_lock(&gpd_list_lock); > + list_for_each_entry(gpd, &gpd_list, gpd_list_node) { > + if (!strcmp(dev_name(&gpd->dev), name)) { > + ret = true; > + break; > + } > + } > + mutex_unlock(&gpd_list_lock); > + > + return ret; > +} > + > /** > * pm_genpd_init - Initialize a generic I/O PM domain object. > * @genpd: PM domain object to initialize. > @@ -2226,6 +2247,7 @@ int pm_genpd_init(struct generic_pm_domain *genpd, > genpd->status = is_off ? GENPD_STATE_OFF : GENPD_STATE_ON; > genpd->device_count = 0; > genpd->provider = NULL; > + genpd->device_id = -ENXIO; > genpd->has_provider = false; > genpd->accounting_time = ktime_get_mono_fast_ns(); > genpd->domain.ops.runtime_suspend = genpd_runtime_suspend; > @@ -2266,7 +2288,18 @@ int pm_genpd_init(struct generic_pm_domain *genpd, > return ret; > > device_initialize(&genpd->dev); > - dev_set_name(&genpd->dev, "%s", genpd->name); > + > + if (!genpd_name_present(genpd->name)) { > + dev_set_name(&genpd->dev, "%s", genpd->name); > + } else { > + ret = ida_alloc(&genpd_ida, GFP_KERNEL); > + if (ret < 0) { > + put_device(&genpd->dev); > + return ret; > + } > + genpd->device_id = ret; > + dev_set_name(&genpd->dev, "%s_%u", genpd->name, genpd->device_id); > + } If we can't assume that the genpd->name is unique, I think we need to hold the gpd_list_lock over this entire new section, until we have added the new genpd in the gpd_list. I am not sure we really want this as it could hurt (theoretically at least) boot/probing on systems where a lot of genpds are being used. That said, I would suggest we go for Dmitry's suggestion to make this genpd provider specific. Let's add a new genpd flag that genpd providers can set, if they need an ida to be tagged on to their device-name. Then we should set that flag for SCMI perf/power domains. [...] Kind regards Uffe
