PCI: Make pci_destroy_dev() concurrent safe

Use an atomic flag instead of the racy check against the device's kobj
parent. We shouldn't be poking into device implementation details at this
level anyway.

Link: https://lore.kernel.org/r/20241022224851.340648-3-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: keithbusch

drivers/pci/pci.h

@@ -469,6 +469,7 @@ static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)
 #define PCI_DEV_ADDED 0
 #define PCI_DPC_RECOVERED 1
 #define PCI_DPC_RECOVERING 2
+#define PCI_DEV_REMOVED 3
 
 static inline void pci_dev_assign_added(struct pci_dev *dev)
 {
@@ -487,6 +488,11 @@ static inline bool pci_dev_is_added(const struct pci_dev *dev)
 	return test_bit(PCI_DEV_ADDED, &dev->priv_flags);
 }
 
+static inline bool pci_dev_test_and_set_removed(struct pci_dev *dev)
+{
+	return test_and_set_bit(PCI_DEV_REMOVED, &dev->priv_flags);
+}
+
 #ifdef CONFIG_PCIEAER
 #include <linux/aer.h>
 

drivers/pci/remove.c

@@ -46,7 +46,7 @@ static void pci_stop_dev(struct pci_dev *dev)
 
 static void pci_destroy_dev(struct pci_dev *dev)
 {
-	if (!dev->dev.kobj.parent)
+	if (pci_dev_test_and_set_removed(dev))
 		return;
 
 	pci_npem_remove(dev);