kevin/linux
1
Fork 0
Code

PCI/pwrctl: Rescan bus on a separate thread

Browse Source 
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.

Link: https://lore.kernel.org/r/20240823093323.33450-3-brgl@bgdev.pl
Fixes: 4565d2652a ("PCI/pwrctl: Add PCI power control core code")
Reported-by: Konrad Dybcio <konradybcio@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2024-08-23 11:33:23 +02:00 committed by Bjorn Helgaas
parent f153658558
commit 8f62819aaa
3 changed files with 27 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
drivers/pci/pwrctl/core.c
View File

@ -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;
}

2
drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
View File

@ -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)

3
include/linux/pci-pwrctl.h
View File

@ -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,