Merge tag 'pci-v4.14-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI fix from Bjorn Helgaas:
 "Revert an attempt to fix a race while enabling upstream bridges
  because it broke iwlwifi firmware loading"

* tag 'pci-v4.14-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  Revert "PCI: Avoid race while enabling upstream bridges"

Author: torvalds

drivers/pci/pci.c

@@ -52,7 +52,6 @@ static void pci_pme_list_scan(struct work_struct *work);
 static LIST_HEAD(pci_pme_list);
 static DEFINE_MUTEX(pci_pme_list_mutex);
 static DECLARE_DELAYED_WORK(pci_pme_work, pci_pme_list_scan);
-static DEFINE_MUTEX(pci_bridge_mutex);
 
 struct pci_pme_device {
 	struct list_head list;
@@ -1351,25 +1350,17 @@ static void pci_enable_bridge(struct pci_dev *dev)
 	if (bridge)
 		pci_enable_bridge(bridge);
 
-	/*
-	 * Hold pci_bridge_mutex to prevent a race when enabling two
-	 * devices below the bridge simultaneously.  The race may cause a
-	 * PCI_COMMAND_MEMORY update to be lost (see changelog).
-	 */
-	mutex_lock(&pci_bridge_mutex);
 	if (pci_is_enabled(dev)) {
 		if (!dev->is_busmaster)
 			pci_set_master(dev);
-		goto end;
+		return;
 	}
 
 	retval = pci_enable_device(dev);
 	if (retval)
 		dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n",
 			retval);
 	pci_set_master(dev);
-end:
-	mutex_unlock(&pci_bridge_mutex);
 }
 
 static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
@@ -1394,7 +1385,7 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
 		return 0;		/* already enabled */
 
 	bridge = pci_upstream_bridge(dev);
-	if (bridge && !pci_is_enabled(bridge))
+	if (bridge)
 		pci_enable_bridge(bridge);
 
 	/* only skip sriov related */