The secondary bus reset may have link side effects that a hot plug
capable port may incorrectly react to. This patch will 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@xxxxxxxxx>
---
drivers/pci/pci.c | 33 +++++++++++++++++++++++++++++++++
drivers/pci/pci.h | 2 ++
drivers/pci/pcie/aer.c | 2 +-
drivers/pci/pcie/err.c | 2 +-
drivers/pci/slot.c | 2 +-
5 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8eb1d869fc98..1d3b7248e5b9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5164,6 +5164,39 @@ 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;
+
+ if (!bus)
+ return -ENOTTY;
+
+ mutex_lock(&pci_slot_mutex);
+ if (!list_empty(&bus->slots)) {
+ struct pci_slot *slot;
+
+ 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
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6e0d1528d471..21bfa30db18d 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -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;
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index a95ceba977bb..a96cea39ee80 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1526,7 +1526,7 @@ 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 */
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 708fd3a0d646..12c1205e1d80 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -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;
}
diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
index e634229ece89..193c909bdd45 100644
--- a/drivers/pci/slot.c
+++ b/drivers/pci/slot.c
@@ -14,7 +14,7 @@
struct kset *pci_slots_kset;
EXPORT_SYMBOL_GPL(pci_slots_kset);
-static DEFINE_MUTEX(pci_slot_mutex);
+DEFINE_MUTEX(pci_slot_mutex);
static ssize_t pci_slot_attr_show(struct kobject *kobj,
struct attribute *attr, char *buf)
--
2.14.4
