From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
If we trigger the bus rescan from sysfs, we'll try to lock the PCI
rescan mutex recursively and deadlock - the platform device will be
populated and probed on the same thread that handles the sysfs write.
Add a workqueue to the pwrctl code on which we schedule the rescan for
controlled PCI devices. While at it: add a new interface for
initializing the pwrctl context where we'd now assign the parent device
address and initialize the workqueue.
Fixes: 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")
Reported-by: Konrad Dybcio <konradybcio@xxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
drivers/pci/pwrctl/core.c | 26 +++++++++++++++++++++++---
drivers/pci/pwrctl/pci-pwrctl-pwrseq.c | 2 +-
include/linux/pci-pwrctl.h | 3 +++
3 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/pwrctl/core.c b/drivers/pci/pwrctl/core.c
index feca26ad2f6a..01d913b60316 100644
--- a/drivers/pci/pwrctl/core.c
+++ b/drivers/pci/pwrctl/core.c
@@ -48,6 +48,28 @@ static int pci_pwrctl_notify(struct notifier_block *nb, unsigned long action,
return NOTIFY_DONE;
}
+static void rescan_work_func(struct work_struct *work)
+{
+ struct pci_pwrctl *pwrctl = container_of(work, struct pci_pwrctl, work);
+
+ pci_lock_rescan_remove();
+ pci_rescan_bus(to_pci_dev(pwrctl->dev->parent)->bus);
+ pci_unlock_rescan_remove();
+}
+
+/**
+ * pci_pwrctl_init() - Initialize the PCI power control context struct
+ *
+ * @pwrctl: PCI power control data
+ * @dev: Parent device
+ */
+void pci_pwrctl_init(struct pci_pwrctl *pwrctl, struct device *dev)
+{
+ pwrctl->dev = dev;
+ INIT_WORK(&pwrctl->work, rescan_work_func);
+}
+EXPORT_SYMBOL_GPL(pci_pwrctl_init);
+
/**
* pci_pwrctl_device_set_ready() - Notify the pwrctl subsystem that the PCI
* device is powered-up and ready to be detected.
@@ -74,9 +96,7 @@ int pci_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl)
if (ret)
return ret;
- pci_lock_rescan_remove();
- pci_rescan_bus(to_pci_dev(pwrctl->dev->parent)->bus);
- pci_unlock_rescan_remove();
+ schedule_work(&pwrctl->work);
return 0;
}
diff --git a/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c b/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
index c7a113a76c0c..f07758c9edad 100644
--- a/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
+++ b/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
@@ -50,7 +50,7 @@ static int pci_pwrctl_pwrseq_probe(struct platform_device *pdev)
if (ret)
return ret;
- data->ctx.dev = dev;
+ pci_pwrctl_init(&data->ctx, dev);
ret = devm_pci_pwrctl_device_set_ready(dev, &data->ctx);
if (ret)
diff --git a/include/linux/pci-pwrctl.h b/include/linux/pci-pwrctl.h
index 45e9cfe740e4..0d23dddf59ec 100644
--- a/include/linux/pci-pwrctl.h
+++ b/include/linux/pci-pwrctl.h
@@ -7,6 +7,7 @@
#define __PCI_PWRCTL_H__
#include <linux/notifier.h>
+#include <linux/workqueue.h>
struct device;
struct device_link;
@@ -41,8 +42,10 @@ struct pci_pwrctl {
/* Private: don't use. */
struct notifier_block nb;
struct device_link *link;
+ struct work_struct work;
};
+void pci_pwrctl_init(struct pci_pwrctl *pwrctl, struct device *dev);
int pci_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl);
void pci_pwrctl_device_unset_ready(struct pci_pwrctl *pwrctl);
int devm_pci_pwrctl_device_set_ready(struct device *dev,
--
2.43.0
