Commit c4eed62a authored by Keith Busch's avatar Keith Busch Committed by Bjorn Helgaas
Browse files

PCI/ERR: Use slot reset if available 



The secondary bus reset may have link side effects that a hotplug capable
port may incorrectly react to.  Use the slot specific reset for hotplug
ports, fixing the undesirable link down-up handling during error
recovering.

Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
[bhelgaas: fold in
https://lore.kernel.org/linux-pci/20180926152326.14821-1-keith.busch@intel.com


for issue reported by Stephen Rothwell <sfr@canb.auug.org.au>]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarSinan Kaya <okaya@kernel.org>
parent 9d938ea5

drivers/pci/pci.c

+37 −0
Original line number Diff line number Diff line
@@ -35,6 +35,8 @@ 
#include <linux/aer.h>

#include "pci.h"



DEFINE_MUTEX(pci_slot_mutex);



const char *pci_power_names[] = {

	"error", "D0", "D1", "D2", "D3hot", "D3cold", "unknown",

};
@@ -5155,6 +5157,41 @@ static int pci_bus_reset(struct pci_bus *bus, int probe) 
	return ret;

}



/**

 * pci_bus_error_reset - reset the bridge's subordinate bus

 * @bridge: The parent device that connects to the bus to reset

 *

 * This function will first try to reset the slots on this bus if the method is

 * available. If slot reset fails or is not available, this will fall back to a

 * secondary bus reset.

 */

int pci_bus_error_reset(struct pci_dev *bridge)

{

	struct pci_bus *bus = bridge->subordinate;

	struct pci_slot *slot;



	if (!bus)

		return -ENOTTY;



	mutex_lock(&pci_slot_mutex);

	if (list_empty(&bus->slots))

		goto bus_reset;



	list_for_each_entry(slot, &bus->slots, list)

		if (pci_probe_reset_slot(slot))

			goto bus_reset;



	list_for_each_entry(slot, &bus->slots, list)

		if (pci_slot_reset(slot, 0))

			goto bus_reset;



	mutex_unlock(&pci_slot_mutex);

	return 0;

bus_reset:

	mutex_unlock(&pci_slot_mutex);

	return pci_bus_reset(bridge->subordinate, 0);

}



/**

 * pci_probe_reset_bus - probe whether a PCI bus can be reset

 * @bus: PCI bus to probe

drivers/pci/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vmai, 


int pci_probe_reset_function(struct pci_dev *dev);

int pci_bridge_secondary_bus_reset(struct pci_dev *dev);

int pci_bus_error_reset(struct pci_dev *dev);



/**

 * struct pci_platform_pm_ops - Firmware PM callbacks
@@ -136,6 +137,7 @@ static inline void pci_remove_legacy_files(struct pci_bus *bus) { return; } 


/* Lock for read/write access to pci device and bus lists */

extern struct rw_semaphore pci_bus_sem;

extern struct mutex pci_slot_mutex;



extern raw_spinlock_t pci_lock;

drivers/pci/pcie/aer.c

+1 −1
Original line number Diff line number Diff line
@@ -1528,7 +1528,7 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev) 
	reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;

	pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, reg32);



	rc = pci_bridge_secondary_bus_reset(dev);

	rc = pci_bus_error_reset(dev);

	pci_printk(KERN_DEBUG, dev, "Root Port link has been reset\n");



	/* Clear Root Error Status */

drivers/pci/pcie/err.c

+1 −1
Original line number Diff line number Diff line
@@ -177,7 +177,7 @@ static pci_ers_result_t default_reset_link(struct pci_dev *dev) 
{

	int rc;



	rc = pci_bridge_secondary_bus_reset(dev);

	rc = pci_bus_error_reset(dev);

	pci_printk(KERN_DEBUG, dev, "downstream link has been reset\n");

	return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;

}

drivers/pci/slot.c

+0 −1
Original line number Diff line number Diff line
@@ -14,7 +14,6 @@ 


struct kset *pci_slots_kset;

EXPORT_SYMBOL_GPL(pci_slots_kset);

static DEFINE_MUTEX(pci_slot_mutex);



static ssize_t pci_slot_attr_show(struct kobject *kobj,

					struct attribute *attr, char *buf)

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