linux-kernel - [PATCH v2 3/7] pmdomain: core: Use dev_name() instead of kobject_get

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Date: Mon, 27 May 2024 16:25:53 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: "Rafael J . Wysocki" <rafael@...nel.org>,
	Sudeep Holla <sudeep.holla@....com>,
	linux-pm@...r.kernel.org
Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Nikunj Kela <nkela@...cinc.com>,
	Prasad Sodagudi <psodagud@...cinc.com>,
	Maulik Shah <quic_mkshah@...cinc.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	linux-rt-users@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/7] pmdomain: core: Use dev_name() instead of kobject_get_path() in debugfs

Using kobject_get_path() means a dynamic memory allocation gets done, which
doesn't work on a PREEMPT_RT based configuration while holding genpd's raw
spinlock.

To fix the problem, let's convert into using the simpler dev_name(). This
means the information about the path doesn't get presented in debugfs, but
hopefully this shouldn't be an issue.

Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---
Changes in v2:
	- New patch.
---
 drivers/pmdomain/core.c | 23 +++--------------------
 1 file changed, 3 insertions(+), 20 deletions(-)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 454fccc38df1..90a65bd09d52 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -3182,7 +3182,6 @@ static int genpd_summary_one(struct seq_file *s,
 		[GENPD_STATE_OFF] = "off"
 	};
 	struct pm_domain_data *pm_data;
-	const char *kobj_path;
 	struct gpd_link *link;
 	char state[16];
 	int ret;
@@ -3215,16 +3214,9 @@ static int genpd_summary_one(struct seq_file *s,
 	}
 
 	list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
-		kobj_path = kobject_get_path(&pm_data->dev->kobj,
-				genpd_is_irq_safe(genpd) ?
-				GFP_ATOMIC : GFP_KERNEL);
-		if (kobj_path == NULL)
-			continue;
-
-		seq_printf(s, "\n    %-50s  ", kobj_path);
+		seq_printf(s, "\n    %-50s  ", dev_name(pm_data->dev));
 		rtpm_status_str(s, pm_data->dev);
 		perf_status_str(s, pm_data->dev);
-		kfree(kobj_path);
 	}
 
 	seq_puts(s, "\n");
@@ -3393,23 +3385,14 @@ static int devices_show(struct seq_file *s, void *data)
 {
 	struct generic_pm_domain *genpd = s->private;
 	struct pm_domain_data *pm_data;
-	const char *kobj_path;
 	int ret = 0;
 
 	ret = genpd_lock_interruptible(genpd);
 	if (ret)
 		return -ERESTARTSYS;
 
-	list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
-		kobj_path = kobject_get_path(&pm_data->dev->kobj,
-				genpd_is_irq_safe(genpd) ?
-				GFP_ATOMIC : GFP_KERNEL);
-		if (kobj_path == NULL)
-			continue;
-
-		seq_printf(s, "%s\n", kobj_path);
-		kfree(kobj_path);
-	}
+	list_for_each_entry(pm_data, &genpd->dev_list, list_node)
+		seq_printf(s, "%s\n", dev_name(pm_data->dev));
 
 	genpd_unlock(genpd);
 	return ret;
-- 
2.34.1