PCI: Add slot reset option to pci_dev_reset()

If the hotplug controller provides a way to reset a slot, use that
before a direct parent bus reset.  Like the bus reset option, this is
only available when a single pci_dev occupies the slot.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d46860898e1f..9407aabc77a3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -22,6 +22,7 @@
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/pm_runtime.h>
+#include <linux/pci_hotplug.h>
 #include <asm-generic/pci-bridge.h>
 #include <asm/setup.h>
 #include "pci.h"
@@ -3256,6 +3257,35 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
         return 0;
 }
 
+static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, int probe)
+{
+        int rc = -ENOTTY;
+
+        if (!hotplug || !try_module_get(hotplug->ops->owner))
+                return rc;
+
+        if (hotplug->ops->reset_slot)
+                rc = hotplug->ops->reset_slot(hotplug, probe);
+
+        module_put(hotplug->ops->owner);
+
+        return rc;
+}
+
+static int pci_dev_reset_slot_function(struct pci_dev *dev, int probe)
+{
+        struct pci_dev *pdev;
+
+        if (dev->subordinate || !dev->slot)
+                return -ENOTTY;
+
+        list_for_each_entry(pdev, &dev->bus->devices, bus_list)
+                if (pdev != dev && pdev->slot == dev->slot)
+                        return -ENOTTY;
+
+        return pci_reset_hotplug_slot(dev->slot->hotplug, probe);
+}
+
 static int __pci_dev_reset(struct pci_dev *dev, int probe)
 {
         int rc;
@@ -3278,6 +3308,10 @@ static int __pci_dev_reset(struct pci_dev *dev, int probe)
         if (rc != -ENOTTY)
                 goto done;
 
+        rc = pci_dev_reset_slot_function(dev, probe);
+        if (rc != -ENOTTY)
+                goto done;
+
         rc = pci_parent_bus_reset(dev, probe);
 done:
         return rc;