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PCI/ERR: Use slot reset if available

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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: Keith 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: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
This commit is contained in:
Keith Busch 2018-09-20 10:27:11 -06:00 committed by Bjorn Helgaas
parent 9d938ea53b
commit c4eed62a21
5 changed files with 41 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
drivers/pci/pci.c
View File

@ -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

2
drivers/pci/pci.h
View File

@ -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;

2
drivers/pci/pcie/aer.c
View File

@ -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 */

2
drivers/pci/pcie/err.c
View File

@ -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;
}

1
drivers/pci/slot.c
View File

@ -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)