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Commit c4ec84c7 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Bjorn Helgaas
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PCI: hotplug: Use global PCI rescan-remove locking 



Multiple race conditions are possible between PCI hotplug and the generic
PCI bus rescan and device removal that can be triggered via sysfs.

To avoid those race conditions make PCI hotplug use global PCI
rescan-remove locking.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 5ef68e88

drivers/pci/hotplug/cpci_hotplug_pci.c

+12 −2
Original line number Diff line number Diff line
@@ -254,9 +254,12 @@ int __ref cpci_configure_slot(struct slot *slot) 
{

	struct pci_dev *dev;

	struct pci_bus *parent;

	int ret = 0;



	dbg("%s - enter", __func__);



	pci_lock_rescan_remove();



	if (slot->dev == NULL) {

		dbg("pci_dev null, finding %02x:%02x:%x",

		    slot->bus->number, PCI_SLOT(slot->devfn), PCI_FUNC(slot->devfn));
@@ -277,7 +280,8 @@ int __ref cpci_configure_slot(struct slot *slot) 
		slot->dev = pci_get_slot(slot->bus, slot->devfn);

		if (slot->dev == NULL) {

			err("Could not find PCI device for slot %02x", slot->number);

			return -ENODEV;

			ret = -ENODEV;

			goto out;

		}

	}

	parent = slot->dev->bus;
@@ -294,8 +298,10 @@ int __ref cpci_configure_slot(struct slot *slot) 


	pci_bus_add_devices(parent);



 out:

	pci_unlock_rescan_remove();

	dbg("%s - exit", __func__);

	return 0;

	return ret;

}



int cpci_unconfigure_slot(struct slot* slot)
@@ -308,6 +314,8 @@ int cpci_unconfigure_slot(struct slot* slot) 
		return -ENODEV;

	}



	pci_lock_rescan_remove();



	list_for_each_entry_safe(dev, temp, &slot->bus->devices, bus_list) {

		if (PCI_SLOT(dev->devfn) != PCI_SLOT(slot->devfn))

			continue;
@@ -318,6 +326,8 @@ int cpci_unconfigure_slot(struct slot* slot) 
	pci_dev_put(slot->dev);

	slot->dev = NULL;



	pci_unlock_rescan_remove();



	dbg("%s - exit", __func__);

	return 0;

}

drivers/pci/hotplug/cpqphp_pci.c

+7 −1
Original line number Diff line number Diff line
@@ -86,6 +86,8 @@ int cpqhp_configure_device (struct controller* ctrl, struct pci_func* func) 
	struct pci_bus *child;

	int num;



	pci_lock_rescan_remove();



	if (func->pci_dev == NULL)

		func->pci_dev = pci_get_bus_and_slot(func->bus,PCI_DEVFN(func->device, func->function));
@@ -100,7 +102,7 @@ int cpqhp_configure_device (struct controller* ctrl, struct pci_func* func) 
		func->pci_dev = pci_get_bus_and_slot(func->bus, PCI_DEVFN(func->device, func->function));

		if (func->pci_dev == NULL) {

			dbg("ERROR: pci_dev still null\n");

			return 0;

			goto out;

		}

	}
@@ -113,6 +115,8 @@ int cpqhp_configure_device (struct controller* ctrl, struct pci_func* func) 


	pci_dev_put(func->pci_dev);



 out:

	pci_unlock_rescan_remove();

	return 0;

}
@@ -123,6 +127,7 @@ int cpqhp_unconfigure_device(struct pci_func* func) 


	dbg("%s: bus/dev/func = %x/%x/%x\n", __func__, func->bus, func->device, func->function);



	pci_lock_rescan_remove();

	for (j=0; j<8 ; j++) {

		struct pci_dev* temp = pci_get_bus_and_slot(func->bus, PCI_DEVFN(func->device, j));

		if (temp) {
@@ -130,6 +135,7 @@ int cpqhp_unconfigure_device(struct pci_func* func) 
			pci_stop_and_remove_bus_device(temp);

		}

	}

	pci_unlock_rescan_remove();

	return 0;

}

drivers/pci/hotplug/ibmphp_core.c

+11 −2
Original line number Diff line number Diff line
@@ -718,6 +718,8 @@ static void ibm_unconfigure_device(struct pci_func *func) 
					func->device, func->function);

	debug("func->device << 3 | 0x0  = %x\n", func->device << 3 | 0x0);



	pci_lock_rescan_remove();



	for (j = 0; j < 0x08; j++) {

		temp = pci_get_bus_and_slot(func->busno, (func->device << 3) | j);

		if (temp) {
@@ -725,7 +727,10 @@ static void ibm_unconfigure_device(struct pci_func *func) 
			pci_dev_put(temp);

		}

	}



	pci_dev_put(func->dev);



	pci_unlock_rescan_remove();

}



/*
@@ -780,6 +785,8 @@ static int ibm_configure_device(struct pci_func *func) 
	int flag = 0;	/* this is to make sure we don't double scan the bus,

					for bridged devices primarily */



	pci_lock_rescan_remove();



	if (!(bus_structure_fixup(func->busno)))

		flag = 1;

	if (func->dev == NULL)
@@ -789,7 +796,7 @@ static int ibm_configure_device(struct pci_func *func) 
	if (func->dev == NULL) {

		struct pci_bus *bus = pci_find_bus(0, func->busno);

		if (!bus)

			return 0;

			goto out;



		num = pci_scan_slot(bus,

				PCI_DEVFN(func->device, func->function));
@@ -800,7 +807,7 @@ static int ibm_configure_device(struct pci_func *func) 
				PCI_DEVFN(func->device, func->function));

		if (func->dev == NULL) {

			err("ERROR... : pci_dev still NULL\n");

			return 0;

			goto out;

		}

	}

	if (!(flag) && (func->dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)) {
@@ -810,6 +817,8 @@ static int ibm_configure_device(struct pci_func *func) 
			pci_bus_add_devices(child);

	}



 out:

	pci_unlock_rescan_remove();

	return 0;

}

drivers/pci/hotplug/pciehp_pci.c

+13 −4
Original line number Diff line number Diff line
@@ -39,22 +39,26 @@ int pciehp_configure_device(struct slot *p_slot) 
	struct pci_dev *dev;

	struct pci_dev *bridge = p_slot->ctrl->pcie->port;

	struct pci_bus *parent = bridge->subordinate;

	int num;

	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", pci_name(dev),

			 pci_domain_nr(parent), parent->number);

		pci_dev_put(dev);

		return -EINVAL;

		ret = -EINVAL;

		goto out;

	}



	num = pci_scan_slot(parent, PCI_DEVFN(0, 0));

	if (num == 0) {

		ctrl_err(ctrl, "No new device found\n");

		return -ENODEV;

		ret = -ENODEV;

		goto out;

	}



	list_for_each_entry(dev, &parent->devices, bus_list)
@@ -73,7 +77,9 @@ int pciehp_configure_device(struct slot *p_slot) 


	pci_bus_add_devices(parent);



	return 0;

 out:

	pci_unlock_rescan_remove();

	return ret;

}



int pciehp_unconfigure_device(struct slot *p_slot)
@@ -90,6 +96,8 @@ int pciehp_unconfigure_device(struct slot *p_slot) 
		 __func__, pci_domain_nr(parent), parent->number);

	pciehp_get_adapter_status(p_slot, &presence);



	pci_lock_rescan_remove();



	/*

	 * Stopping an SR-IOV PF device removes all the associated VFs,

	 * which will update the bus->devices list and confuse the
@@ -124,5 +132,6 @@ int pciehp_unconfigure_device(struct slot *p_slot) 
		pci_dev_put(dev);

	}



	pci_unlock_rescan_remove();

	return rc;

}

drivers/pci/hotplug/rpadlpar_core.c

+14 −5
Original line number Diff line number Diff line
@@ -354,10 +354,15 @@ int dlpar_remove_pci_slot(char *drc_name, struct device_node *dn) 
{

	struct pci_bus *bus;

	struct slot *slot;

	int ret = 0;



	pci_lock_rescan_remove();



	bus = pcibios_find_pci_bus(dn);

	if (!bus)

		return -EINVAL;

	if (!bus) {

		ret = -EINVAL;

		goto out;

	}



	pr_debug("PCI: Removing PCI slot below EADS bridge %s\n",

		 bus->self ? pci_name(bus->self) : "<!PHB!>");
@@ -371,7 +376,8 @@ int dlpar_remove_pci_slot(char *drc_name, struct device_node *dn) 
			printk(KERN_ERR

				"%s: unable to remove hotplug slot %s\n",

				__func__, drc_name);

			return -EIO;

			ret = -EIO;

			goto out;

		}

	}
@@ -382,7 +388,8 @@ int dlpar_remove_pci_slot(char *drc_name, struct device_node *dn) 
	if (pcibios_unmap_io_space(bus)) {

		printk(KERN_ERR "%s: failed to unmap bus range\n",

			__func__);

		return -ERANGE;

		ret = -ERANGE;

		goto out;

	}



	/* Remove the EADS bridge device itself */
@@ -390,7 +397,9 @@ int dlpar_remove_pci_slot(char *drc_name, struct device_node *dn) 
	pr_debug("PCI: Now removing bridge device %s\n", pci_name(bus->self));

	pci_stop_and_remove_bus_device(bus->self);



	return 0;

 out:

	pci_unlock_rescan_remove();

	return ret;

}



/**