linux-kernel - [PATCH v1 01/23] genirq/chip: Change irq_chip_pm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4723896.LvFx2qVVIh@rafael.j.wysocki>
Date: Mon, 22 Dec 2025 20:50:10 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>, Ulf Hansson <ulf.hansson@...aro.org>,
 Brian Norris <briannorris@...omium.org>, Thomas Gleixner <tglx@...utronix.de>
Subject:
 [PATCH v1 01/23] genirq/chip: Change irq_chip_pm_put() return type to void

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

The irq_chip_pm_put() return value is only used in __irq_do_set_handler()
to trigger a WARN_ON() if it is negative, but doing so is not useful
because irq_chip_pm_put() simply passes the pm_runtime_put() return value
to its callers.

Returning an error code from pm_runtime_put() merely means that it has
not queued up a work item to check whether or not the device can be
suspended and there are many perfectly valid situations in which that
can happen, like after writing "on" to the devices' runtime PM "control"
attribute in sysfs for one example.

For this reason, modify irq_chip_pm_put() to discard the pm_runtime_put()
return value, change its return type to void, and drop the WARN_ON()
around the irq_chip_pm_put() invocation from __irq_do_set_handler().
Also update the irq_chip_pm_put() kerneldoc comment to be more accurate.

This will facilitate a planned change of the pm_runtime_put() return
type to void in the future.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

This patch is part of a series, but it doesn't depend on anything else
in that series.  The last patch in the series depends on it.

It can be applied by itself and if you decide to do so, please let me
know.

Otherwise, an ACK or equivalent will be appreciated, but also the lack
of specific criticism will be eventually regarded as consent.

---
 include/linux/irq.h |    2 +-
 kernel/irq/chip.c   |   22 +++++++++++-----------
 2 files changed, 12 insertions(+), 12 deletions(-)

--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -659,7 +659,7 @@ extern void handle_percpu_devid_fasteoi_

 extern int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg);
 extern int irq_chip_pm_get(struct irq_data *data);
-extern int irq_chip_pm_put(struct irq_data *data);
+extern void irq_chip_pm_put(struct irq_data *data);
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
 extern void handle_fasteoi_ack_irq(struct irq_desc *desc);
 extern void handle_fasteoi_mask_irq(struct irq_desc *desc);
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -995,7 +995,7 @@ __irq_do_set_handler(struct irq_desc *de
 		irq_state_set_disabled(desc);
 		if (is_chained) {
 			desc->action = NULL;
-			WARN_ON(irq_chip_pm_put(irq_desc_get_irq_data(desc)));
+			irq_chip_pm_put(irq_desc_get_irq_data(desc));
 		}
 		desc->depth = 1;
 	}
@@ -1551,20 +1551,20 @@ int irq_chip_pm_get(struct irq_data *dat
 }

 /**
- * irq_chip_pm_put - Disable power for an IRQ chip
+ * irq_chip_pm_put - Drop a PM reference on an IRQ chip
  * @data:	Pointer to interrupt specific data
  *
- * Disable the power to the IRQ chip referenced by the interrupt data
- * structure, belongs. Note that power will only be disabled, once this
- * function has been called for all IRQs that have called irq_chip_pm_get().
+ * Drop a power management reference, acquired via irq_chip_pm_get(), on the IRQ
+ * chip represented by the interrupt data structure.
+ *
+ * Note that this will not disable power to the IRQ chip until this function
+ * has been called for all IRQs that have called irq_chip_pm_get() and it may
+ * not disable power at all (which may be prefented by user space, for example).
  */
-int irq_chip_pm_put(struct irq_data *data)
+void irq_chip_pm_put(struct irq_data *data)
 {
 	struct device *dev = irq_get_pm_device(data);
-	int retval = 0;
-
-	if (IS_ENABLED(CONFIG_PM) && dev)
-		retval = pm_runtime_put(dev);

-	return (retval < 0) ? retval : 0;
+	if (dev)
+		pm_runtime_put(dev);
 }