github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-13 00:28:54 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

PCI: Make reset_subordinate hotplug safe

Browse Source 
Use the slot reset method when resetting the bridge if the bus contains
hot plug slots. This fixes spurious hot plug events that are triggered
by the secondary bus reset that bypasses the slot's detection disabling.

Resetting a bridge's subordinate bus can be done like this:

  # echo 1 > /sys/bus/pci/devices/0000:50:01.0/reset_subordinate

Prior to this patch, an example kernel message may show something like:

  pcieport 0000:50:01.0: pciehp: Slot(40): Link Down

With this change, the pciehp driver ignores the link event during the
reset, so may show this message instead:

  pcieport 0000:50:01.0: pciehp: Slot(40): Link Down/Up ignored

Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://patch.msgid.link/20260217160836.2709885-4-kbusch@meta.com
This commit is contained in:
Keith Busch 2026-02-17 08:08:36 -08:00 committed by Bjorn Helgaas
parent 102c8b26b5
commit 8238cb69c0
3 changed files with 79 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/pci/pci-sysfs.c
View File

@ -553,7 +553,6 @@ static ssize_t reset_subordinate_store(struct device *dev,
const char *buf, size_t count)
{
struct pci_dev *pdev = to_pci_dev(dev);
struct pci_bus *bus = pdev->subordinate;
unsigned long val;
if (!capable(CAP_SYS_ADMIN))
@ -563,7 +562,7 @@ static ssize_t reset_subordinate_store(struct device *dev,
return -EINVAL;
if (val) {
int ret = pci_try_reset_bus(bus);
int ret = pci_try_reset_bridge(pdev);
if (ret)
return ret;

125
drivers/pci/pci.c
View File

@ -5596,60 +5596,13 @@ static int pci_bus_reset(struct pci_bus *bus, bool 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, PCI_RESET_DO_RESET))
goto bus_reset;
mutex_unlock(&pci_slot_mutex);
return 0;
bus_reset:
mutex_unlock(&pci_slot_mutex);
return pci_bus_reset(bridge->subordinate, PCI_RESET_DO_RESET);
}
/**
* pci_probe_reset_bus - probe whether a PCI bus can be reset
* @bus: PCI bus to probe
*
* Return 0 if bus can be reset, negative if a bus reset is not supported.
*/
int pci_probe_reset_bus(struct pci_bus *bus)
{
return pci_bus_reset(bus, PCI_RESET_PROBE);
}
EXPORT_SYMBOL_GPL(pci_probe_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)
static int pci_try_reset_bus(struct pci_bus *bus)
{
int rc;
@ -5669,6 +5622,82 @@ int pci_try_reset_bus(struct pci_bus *bus)
return rc;
}
#define PCI_RESET_RESTORE true
#define PCI_RESET_NO_RESTORE false
/**
* pci_reset_bridge - reset a bridge's subordinate bus
* @bridge: bridge that connects to the bus to reset
* @restore: when true use a reset method that invokes pci_dev_restore() post
* reset for affected devices
*
* 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.
*/
static int pci_reset_bridge(struct pci_dev *bridge, bool restore)
{
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) {
int ret;
if (restore)
ret = pci_try_reset_slot(slot);
else
ret = pci_slot_reset(slot, PCI_RESET_DO_RESET);
if (ret)
goto bus_reset;
}
mutex_unlock(&pci_slot_mutex);
return 0;
bus_reset:
mutex_unlock(&pci_slot_mutex);
if (restore)
return pci_try_reset_bus(bus);
return pci_bus_reset(bridge->subordinate, PCI_RESET_DO_RESET);
}
/**
* pci_bus_error_reset - reset the bridge's subordinate bus
* @bridge: The parent device that connects to the bus to reset
*/
int pci_bus_error_reset(struct pci_dev *bridge)
{
return pci_reset_bridge(bridge, PCI_RESET_NO_RESTORE);
}
int pci_try_reset_bridge(struct pci_dev *bridge)
{
return pci_reset_bridge(bridge, PCI_RESET_RESTORE);
}
/**
* pci_probe_reset_bus - probe whether a PCI bus can be reset
* @bus: PCI bus to probe
*
* Return 0 if bus can be reset, negative if a bus reset is not supported.
*/
int pci_probe_reset_bus(struct pci_bus *bus)
{
return pci_bus_reset(bus, PCI_RESET_PROBE);
}
EXPORT_SYMBOL_GPL(pci_probe_reset_bus);
/**
* pci_reset_bus - Try to reset a PCI bus
* @pdev: top level PCI device to reset via slot/bus

2
drivers/pci/pci.h
View File

@ -231,7 +231,7 @@ bool pci_reset_supported(struct pci_dev *dev);
void pci_init_reset_methods(struct pci_dev *dev);
int pci_bridge_secondary_bus_reset(struct pci_dev *dev);
int pci_bus_error_reset(struct pci_dev *dev);
int pci_try_reset_bus(struct pci_bus *bus);
int pci_try_reset_bridge(struct pci_dev *bridge);
struct pci_cap_saved_data {
u16 cap_nr;