diff --git a/arch/s390/pci/pci_sysfs.c b/arch/s390/pci/pci_sysfs.c index a433ba01a317..215f17437a4f 100644 --- a/arch/s390/pci/pci_sysfs.c +++ b/arch/s390/pci/pci_sysfs.c @@ -13,6 +13,8 @@ #include #include +#include "../../../drivers/pci/pci.h" + #include #define zpci_attr(name, fmt, member) \ @@ -49,31 +51,50 @@ static DEVICE_ATTR_RO(mio_enabled); static ssize_t recover_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { + struct kernfs_node *kn; struct pci_dev *pdev = to_pci_dev(dev); struct zpci_dev *zdev = to_zpci(pdev); - int ret; + int ret = 0; - if (!device_remove_file_self(dev, attr)) - return count; + /* Can't use device_remove_self() here as that would lead us to lock + * the pci_rescan_remove_lock while holding the device' kernfs lock. + * This would create a possible deadlock with disable_slot() which is + * not directly protected by the device' kernfs lock but takes it + * during the device removal which happens under + * pci_rescan_remove_lock. + * + * This is analogous to sdev_store_delete() in + * drivers/scsi/scsi_sysfs.c + */ + kn = sysfs_break_active_protection(&dev->kobj, &attr->attr); + WARN_ON_ONCE(!kn); + /* device_remove_file() serializes concurrent calls ignoring all but + * the first + */ + device_remove_file(dev, attr); + /* A concurrent call to recover_store() may slip between + * sysfs_break_active_protection() and the sysfs file removal. + * Once it unblocks from pci_lock_rescan_remove() the original pdev + * will already be removed. + */ pci_lock_rescan_remove(); - pci_stop_and_remove_bus_device(pdev); - ret = zpci_disable_device(zdev); - if (ret) - goto error; + if (pci_dev_is_added(pdev)) { + pci_stop_and_remove_bus_device(pdev); + ret = zpci_disable_device(zdev); + if (ret) + goto out; - ret = zpci_enable_device(zdev); - if (ret) - goto error; - - pci_rescan_bus(zdev->bus); + ret = zpci_enable_device(zdev); + if (ret) + goto out; + pci_rescan_bus(zdev->bus); + } +out: pci_unlock_rescan_remove(); - - return count; - -error: - pci_unlock_rescan_remove(); - return ret; + if (kn) + sysfs_unbreak_active_protection(kn); + return ret ? ret : count; } static DEVICE_ATTR_WO(recover);