1 files changed, 55 insertions, 48 deletions

diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
index 19f30a9f461d..65e50bee1a8c 100644
--- a/drivers/pci/hotplug/pciehp_pci.c
+++ b/drivers/pci/hotplug/pciehp_pci.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0+
 /*
  * PCI Express Hot Plug Controller Driver
  *
@@ -8,45 +9,42 @@
  *
  * All rights reserved.
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT.  See the GNU General Public License for more
- * details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
  * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
  *
  */
 
-#include <linux/module.h>
+#define dev_fmt(fmt) "pciehp: " fmt
+
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/pci.h>
 #include "../pci.h"
 #include "pciehp.h"
 
-int pciehp_configure_device(struct slot *p_slot)
+/**
+ * pciehp_configure_device() - enumerate PCI devices below a hotplug bridge
+ * @ctrl: PCIe hotplug controller
+ *
+ * Enumerate PCI devices below a hotplug bridge and add them to the system.
+ * Return 0 on success, %-EEXIST if the devices are already enumerated or
+ * %-ENODEV if enumeration failed.
+ */
+int pciehp_configure_device(struct controller *ctrl)
 {
 	struct pci_dev *dev;
-	struct pci_dev *bridge = p_slot->ctrl->pcie->port;
+	struct pci_dev *bridge = ctrl->pcie->port;
 	struct pci_bus *parent = bridge->subordinate;
 	int num, ret = 0;
-	struct controller *ctrl = p_slot->ctrl;
 
 	pci_lock_rescan_remove();
 
 	dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
 	if (dev) {
-		ctrl_err(ctrl, "Device %s already exists at %04x:%02x:00, cannot hot-add\n",
+		/*
+		 * The device is already there. Either configured by the
+		 * boot firmware or a previous hotplug event.
+		 */
+		ctrl_dbg(ctrl, "Device %s already exists at %04x:%02x:00, skipping hot-add\n",
 			 pci_name(dev), pci_domain_nr(parent), parent->number);
 		pci_dev_put(dev);
 		ret = -EEXIST;
@@ -60,32 +58,51 @@ int pciehp_configure_device(struct slot *p_slot)
 		goto out;
 	}
 
-	list_for_each_entry(dev, &parent->devices, bus_list)
-		if (pci_is_bridge(dev))
-			pci_hp_add_bridge(dev);
+	for_each_pci_bridge(dev, parent)
+		pci_hp_add_bridge(dev);
 
 	pci_assign_unassigned_bridge_resources(bridge);
 	pcie_bus_configure_settings(parent);
+
+	/*
+	 * Release reset_lock during driver binding
+	 * to avoid AB-BA deadlock with device_lock.
+	 */
+	up_read(&ctrl->reset_lock);
 	pci_bus_add_devices(parent);
+	down_read_nested(&ctrl->reset_lock, ctrl->depth);
+
+	dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
+	ctrl->dsn = pci_get_dsn(dev);
+	pci_dev_put(dev);
 
  out:
 	pci_unlock_rescan_remove();
 	return ret;
 }
 
-int pciehp_unconfigure_device(struct slot *p_slot)
+/**
+ * pciehp_unconfigure_device() - remove PCI devices below a hotplug bridge
+ * @ctrl: PCIe hotplug controller
+ * @presence: whether the card is still present in the slot;
+ *	true for safe removal via sysfs or an Attention Button press,
+ *	false for surprise removal
+ *
+ * Unbind PCI devices below a hotplug bridge from their drivers and remove
+ * them from the system.  Safely removed devices are quiesced.  Surprise
+ * removed devices are marked as such to prevent further accesses.
+ */
+void pciehp_unconfigure_device(struct controller *ctrl, bool presence)
 {
-	int rc = 0;
-	u8 bctl = 0;
-	u8 presence = 0;
 	struct pci_dev *dev, *temp;
-	struct pci_bus *parent = p_slot->ctrl->pcie->port->subordinate;
+	struct pci_bus *parent = ctrl->pcie->port->subordinate;
 	u16 command;
-	struct controller *ctrl = p_slot->ctrl;
 
 	ctrl_dbg(ctrl, "%s: domain:bus:dev = %04x:%02x:00\n",
 		 __func__, pci_domain_nr(parent), parent->number);
-	pciehp_get_adapter_status(p_slot, &presence);
+
+	if (!presence)
+		pci_walk_bus(parent, pci_dev_set_disconnected, NULL);
 
 	pci_lock_rescan_remove();
 
@@ -98,24 +115,15 @@ int pciehp_unconfigure_device(struct slot *p_slot)
 	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
 					 bus_list) {
 		pci_dev_get(dev);
-		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE && presence) {
-			pci_read_config_byte(dev, PCI_BRIDGE_CONTROL, &bctl);
-			if (bctl & PCI_BRIDGE_CTL_VGA) {
-				ctrl_err(ctrl,
-					 "Cannot remove display device %s\n",
-					 pci_name(dev));
-				pci_dev_put(dev);
-				rc = -EINVAL;
-				break;
-			}
-		}
-		if (!presence) {
-			pci_dev_set_disconnected(dev, NULL);
-			if (pci_has_subordinate(dev))
-				pci_walk_bus(dev->subordinate,
-					     pci_dev_set_disconnected, NULL);
-		}
+
+		/*
+		 * Release reset_lock during driver unbinding
+		 * to avoid AB-BA deadlock with device_lock.
+		 */
+		up_read(&ctrl->reset_lock);
 		pci_stop_and_remove_bus_device(dev);
+		down_read_nested(&ctrl->reset_lock, ctrl->depth);
+
 		/*
 		 * Ensure that no new Requests will be generated from
 		 * the device.
@@ -130,5 +138,4 @@ int pciehp_unconfigure_device(struct slot *p_slot)
 	}
 
 	pci_unlock_rescan_remove();
-	return rc;
 }