From: Keith Busch <keith.busch@xxxxxxxxx> [ Upstream commit c4eed62a214330908eec11b0dc170d34fa50b412 ] 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@xxxxxxxxx> [bhelgaas: fold in https://lore.kernel.org/linux-pci/20180926152326.14821-1-keith.busch@xxxxxxxxx for issue reported by Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>] Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Reviewed-by: Sinan Kaya <okaya@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/pci/pci.c | 37 +++++++++++++++++++++++++++++++++++++ drivers/pci/pci.h | 2 ++ drivers/pci/pcie/aer.c | 2 +- drivers/pci/pcie/err.c | 2 +- drivers/pci/slot.c | 1 - 5 files changed, 41 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 2baf1f82f8933..c9f51fc24563c 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -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", }; @@ -5191,6 +5193,41 @@ 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 diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index ab25752f00d96..e9ede82ee2c25 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 5c3ea7254c6ae..1563e22600eca 100644 --- a/drivers/pci/pcie/aer.c +++ b/drivers/pci/pcie/aer.c @@ -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 */ diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c index 708fd3a0d6466..12c1205e1d804 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 e634229ece895..a32897f83ee51 100644 --- a/drivers/pci/slot.c +++ b/drivers/pci/slot.c @@ -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) -- 2.20.1
