Merge branch 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[~andy/linux] / drivers / pci / pci-driver.c

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 9042fdbd724405bc96808ed699a1d543fcf17c17..25f0bc6591645707bb3b452bbaa4c28bee0efc59 100644 (file)
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -19,6 +19,7 @@
 #include <linux/cpu.h>
 #include <linux/pm_runtime.h>
 #include <linux/suspend.h>
+#include <linux/kexec.h>
 #include "pci.h"
 
 struct pci_dynid {
@@ -288,12 +289,27 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
        int error, node;
        struct drv_dev_and_id ddi = { drv, dev, id };
 
-       /* Execute driver initialization on node where the device's
-          bus is attached to.  This way the driver likely allocates
-          its local memory on the right node without any need to
-          change it. */
+       /*
+        * Execute driver initialization on node where the device is
+        * attached.  This way the driver likely allocates its local memory
+        * on the right node.
+        */
        node = dev_to_node(&dev->dev);
-       if (node >= 0) {
+
+       /*
+        * On NUMA systems, we are likely to call a PF probe function using
+        * work_on_cpu().  If that probe calls pci_enable_sriov() (which
+        * adds the VF devices via pci_bus_add_device()), we may re-enter
+        * this function to call the VF probe function.  Calling
+        * work_on_cpu() again will cause a lockdep warning.  Since VFs are
+        * always on the same node as the PF, we can work around this by
+        * avoiding work_on_cpu() when we're already on the correct node.
+        *
+        * Preemption is enabled, so it's theoretically unsafe to use
+        * numa_node_id(), but even if we run the probe function on the
+        * wrong node, it should be functionally correct.
+        */
+       if (node >= 0 && node != numa_node_id()) {
                int cpu;
 
                get_online_cpus();
@@ -305,6 +321,7 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
                put_online_cpus();
        } else
                error = local_pci_probe(&ddi);
+
        return error;
 }
 
@@ -399,12 +416,17 @@ static void pci_device_shutdown(struct device *dev)
        pci_msi_shutdown(pci_dev);
        pci_msix_shutdown(pci_dev);
 
+#ifdef CONFIG_KEXEC
        /*
-        * Turn off Bus Master bit on the device to tell it to not
-        * continue to do DMA. Don't touch devices in D3cold or unknown states.
+        * If this is a kexec reboot, turn off Bus Master bit on the
+        * device to tell it to not continue to do DMA. Don't touch
+        * devices in D3cold or unknown states.
+        * If it is not a kexec reboot, firmware will hit the PCI
+        * devices with big hammer and stop their DMA any way.
         */
-       if (pci_dev->current_state <= PCI_D3hot)
+       if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot))
                pci_clear_master(pci_dev);
+#endif
 }
 
 #ifdef CONFIG_PM