Commit 6e2d98dc authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'pci/reset' into next 

* pci/reset:
  vfio-pci: Use pci "try" reset interface
  PCI: Add pci_try_reset_function(), pci_try_reset_slot(), pci_try_reset_bus()
parents 40304618 890ed578

drivers/pci/pci.c

+155 −0
Original line number Diff line number Diff line
@@ -3250,6 +3250,18 @@ static void pci_dev_lock(struct pci_dev *dev) 
	device_lock(&dev->dev);

}



/* Return 1 on successful lock, 0 on contention */

static int pci_dev_trylock(struct pci_dev *dev)

{

	if (pci_cfg_access_trylock(dev)) {

		if (device_trylock(&dev->dev))

			return 1;

		pci_cfg_access_unlock(dev);

	}



	return 0;

}



static void pci_dev_unlock(struct pci_dev *dev)

{

	device_unlock(&dev->dev);
@@ -3393,6 +3405,34 @@ int pci_reset_function(struct pci_dev *dev) 
}

EXPORT_SYMBOL_GPL(pci_reset_function);



/**

 * pci_try_reset_function - quiesce and reset a PCI device function

 * @dev: PCI device to reset

 *

 * Same as above, except return -EAGAIN if unable to lock device.

 */

int pci_try_reset_function(struct pci_dev *dev)

{

	int rc;



	rc = pci_dev_reset(dev, 1);

	if (rc)

		return rc;



	pci_dev_save_and_disable(dev);



	if (pci_dev_trylock(dev)) {

		rc = __pci_dev_reset(dev, 0);

		pci_dev_unlock(dev);

	} else

		rc = -EAGAIN;



	pci_dev_restore(dev);



	return rc;

}

EXPORT_SYMBOL_GPL(pci_try_reset_function);



/* Lock devices from the top of the tree down */

static void pci_bus_lock(struct pci_bus *bus)

{
@@ -3417,6 +3457,32 @@ static void pci_bus_unlock(struct pci_bus *bus) 
	}

}



/* Return 1 on successful lock, 0 on contention */

static int pci_bus_trylock(struct pci_bus *bus)

{

	struct pci_dev *dev;



	list_for_each_entry(dev, &bus->devices, bus_list) {

		if (!pci_dev_trylock(dev))

			goto unlock;

		if (dev->subordinate) {

			if (!pci_bus_trylock(dev->subordinate)) {

				pci_dev_unlock(dev);

				goto unlock;

			}

		}

	}

	return 1;



unlock:

	list_for_each_entry_continue_reverse(dev, &bus->devices, bus_list) {

		if (dev->subordinate)

			pci_bus_unlock(dev->subordinate);

		pci_dev_unlock(dev);

	}

	return 0;

}



/* Lock devices from the top of the tree down */

static void pci_slot_lock(struct pci_slot *slot)

{
@@ -3445,6 +3511,37 @@ static void pci_slot_unlock(struct pci_slot *slot) 
	}

}



/* Return 1 on successful lock, 0 on contention */

static int pci_slot_trylock(struct pci_slot *slot)

{

	struct pci_dev *dev;



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

		if (!dev->slot || dev->slot != slot)

			continue;

		if (!pci_dev_trylock(dev))

			goto unlock;

		if (dev->subordinate) {

			if (!pci_bus_trylock(dev->subordinate)) {

				pci_dev_unlock(dev);

				goto unlock;

			}

		}

	}

	return 1;



unlock:

	list_for_each_entry_continue_reverse(dev,

					     &slot->bus->devices, bus_list) {

		if (!dev->slot || dev->slot != slot)

			continue;

		if (dev->subordinate)

			pci_bus_unlock(dev->subordinate);

		pci_dev_unlock(dev);

	}

	return 0;

}



/* Save and disable devices from the top of the tree down */

static void pci_bus_save_and_disable(struct pci_bus *bus)

{
@@ -3568,6 +3665,35 @@ int pci_reset_slot(struct pci_slot *slot) 
}

EXPORT_SYMBOL_GPL(pci_reset_slot);



/**

 * pci_try_reset_slot - Try to reset a PCI slot

 * @slot: PCI slot to reset

 *

 * Same as above except return -EAGAIN if the slot cannot be locked

 */

int pci_try_reset_slot(struct pci_slot *slot)

{

	int rc;



	rc = pci_slot_reset(slot, 1);

	if (rc)

		return rc;



	pci_slot_save_and_disable(slot);



	if (pci_slot_trylock(slot)) {

		might_sleep();

		rc = pci_reset_hotplug_slot(slot->hotplug, 0);

		pci_slot_unlock(slot);

	} else

		rc = -EAGAIN;



	pci_slot_restore(slot);



	return rc;

}

EXPORT_SYMBOL_GPL(pci_try_reset_slot);



static int pci_bus_reset(struct pci_bus *bus, int probe)

{

	if (!bus->self)
@@ -3626,6 +3752,35 @@ int pci_reset_bus(struct pci_bus *bus) 
}

EXPORT_SYMBOL_GPL(pci_reset_bus);



/**

 * pci_try_reset_bus - Try to reset a PCI bus

 * @bus: top level PCI bus to reset

 *

 * Same as above except return -EAGAIN if the bus cannot be locked

 */

int pci_try_reset_bus(struct pci_bus *bus)

{

	int rc;



	rc = pci_bus_reset(bus, 1);

	if (rc)

		return rc;



	pci_bus_save_and_disable(bus);



	if (pci_bus_trylock(bus)) {

		might_sleep();

		pci_reset_bridge_secondary_bus(bus->self);

		pci_bus_unlock(bus);

	} else

		rc = -EAGAIN;



	pci_bus_restore(bus);



	return rc;

}

EXPORT_SYMBOL_GPL(pci_try_reset_bus);



/**

 * pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count

 * @dev: PCI device to query

drivers/vfio/pci/vfio_pci.c

+9 −20
Original line number Diff line number Diff line
@@ -139,25 +139,14 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev) 
	pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE);



	/*

	 * Careful, device_lock may already be held.  This is the case if

	 * a driver unbind is blocked.  Try to get the locks ourselves to

	 * prevent a deadlock.

	 * Try to reset the device.  The success of this is dependent on

	 * being able to lock the device, which is not always possible.

	 */

	if (vdev->reset_works) {

		bool reset_done = false;



		if (pci_cfg_access_trylock(pdev)) {

			if (device_trylock(&pdev->dev)) {

				__pci_reset_function_locked(pdev);

				reset_done = true;

				device_unlock(&pdev->dev);

			}

			pci_cfg_access_unlock(pdev);

		}



		if (!reset_done)

			pr_warn("%s: Unable to acquire locks for reset of %s\n",

				__func__, dev_name(&pdev->dev));

		int ret = pci_try_reset_function(pdev);

		if (ret)

			pr_warn("%s: Failed to reset device %s (%d)\n",

				__func__, dev_name(&pdev->dev), ret);

	}



	pci_restore_state(pdev);
@@ -514,7 +503,7 @@ static long vfio_pci_ioctl(void *device_data, 


	} else if (cmd == VFIO_DEVICE_RESET) {

		return vdev->reset_works ?

			pci_reset_function(vdev->pdev) : -EINVAL;

			pci_try_reset_function(vdev->pdev) : -EINVAL;



	} else if (cmd == VFIO_DEVICE_GET_PCI_HOT_RESET_INFO) {

		struct vfio_pci_hot_reset_info hdr;
@@ -684,8 +673,8 @@ static long vfio_pci_ioctl(void *device_data, 
						    &info, slot);

		if (!ret)

			/* User has access, do the reset */

			ret = slot ? pci_reset_slot(vdev->pdev->slot) :

				     pci_reset_bus(vdev->pdev->bus);

			ret = slot ? pci_try_reset_slot(vdev->pdev->slot) :

				     pci_try_reset_bus(vdev->pdev->bus);



hot_reset_release:

		for (i--; i >= 0; i--)

include/linux/pci.h

+3 −0
Original line number Diff line number Diff line
@@ -949,10 +949,13 @@ int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed, 
int __pci_reset_function(struct pci_dev *dev);

int __pci_reset_function_locked(struct pci_dev *dev);

int pci_reset_function(struct pci_dev *dev);

int pci_try_reset_function(struct pci_dev *dev);

int pci_probe_reset_slot(struct pci_slot *slot);

int pci_reset_slot(struct pci_slot *slot);

int pci_try_reset_slot(struct pci_slot *slot);

int pci_probe_reset_bus(struct pci_bus *bus);

int pci_reset_bus(struct pci_bus *bus);

int pci_try_reset_bus(struct pci_bus *bus);

void pci_reset_bridge_secondary_bus(struct pci_dev *dev);

void pci_update_resource(struct pci_dev *dev, int resno);

int __must_check pci_assign_resource(struct pci_dev *dev, int i);