Merge tag 'pci-v4.14-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaa...
authorLinus Torvalds <torvalds@linux-foundation.org>
Sat, 16 Sep 2017 03:25:06 +0000 (20:25 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 16 Sep 2017 03:25:06 +0000 (20:25 -0700)
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"

drivers/pci/pci.c

index b0002daa50f3bb98dd0c0e40488e033f00a2ee0a..6078dfc11b112a88aec1c58eb911de9f996b6644 100644 (file)
@@ -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;
@@ -1351,16 +1350,10 @@ 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);
@@ -1368,8 +1361,6 @@ static void pci_enable_bridge(struct pci_dev *dev)
                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 */