[PATCHv4 next 1/3] pci: Add is_removed state

[Keith Busch <keith.busch@intel.com>]

This adds a new state for devices that were once in the system, but
unexpectedly removed. This is so device tear down functions can observe
the device is not accessible so it may skip attempting to initialize
the hardware.

The pciehp and pcie-dpc drivers are aware of when the link is down,
so these explicitly set this flag when its handlers detect the device
is gone.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Cc: Lukas Wunner <lukas@wunner.de>
---
 drivers/pci/hotplug/pciehp_pci.c | 5 +++++
 drivers/pci/pcie/pcie-dpc.c      | 4 ++++
 include/linux/pci.h              | 7 +++++++
 3 files changed, 16 insertions(+)

diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
index 9e69403..7560961 100644
--- a/drivers/pci/hotplug/pciehp_pci.c
+++ b/drivers/pci/hotplug/pciehp_pci.c
@@ -109,6 +109,11 @@ int pciehp_unconfigure_device(struct slot *p_slot)
 				break;
 			}
 		}
+		if (!presence) {
+			pci_set_removed(dev, NULL);
+			if (pci_has_subordinate(dev))
+				pci_walk_bus(dev->subordinate, pci_set_removed, NULL);
+		}
 		pci_stop_and_remove_bus_device(dev);
 		/*
 		 * Ensure that no new Requests will be generated from
diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
index 9811b14..7818c88 100644
--- a/drivers/pci/pcie/pcie-dpc.c
+++ b/drivers/pci/pcie/pcie-dpc.c
@@ -14,6 +14,7 @@
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/pcieport_if.h>
+#include "../pci.h"
 
 struct dpc_dev {
 	struct pcie_device	*dev;
@@ -46,6 +47,9 @@ static void interrupt_event_handler(struct work_struct *work)
 	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
 					 bus_list) {
 		pci_dev_get(dev);
+		pci_set_removed(dev, NULL);
+		if (pci_has_subordinate(dev))
+			pci_walk_bus(dev->subordinate, pci_set_removed, NULL);
 		pci_stop_and_remove_bus_device(dev);
 		pci_dev_put(dev);
 	}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 0e49f70..2115d19 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -341,6 +341,7 @@ struct pci_dev {
 	unsigned int	multifunction:1;/* Part of multi-function device */
 	/* keep track of device state */
 	unsigned int	is_added:1;
+	unsigned int	is_removed:1;	/* device was surprise removed */
 	unsigned int	is_busmaster:1; /* device is busmaster */
 	unsigned int	no_msi:1;	/* device may not use msi */
 	unsigned int	no_64bit_msi:1; /* device may only use 32-bit MSIs */
@@ -417,6 +418,12 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
 	return (pdev->error_state != pci_channel_io_normal);
 }
 
+static inline int pci_set_removed(struct pci_dev *pdev, void *unused)
+{
+	pdev->is_removed = 1;
+	return 0;
+}
+
 struct pci_host_bridge {
 	struct device dev;
 	struct pci_bus *bus;		/* root bus */
-- 
2.7.2