From: Jiang Liu <liuj97@xxxxxxxxx> This is the second take to resolve race conditions when hot-plugging PCI devices/host bridges. Instead of using a globla lock to serialize all hotplug operations as in previous version, now we introduce a state machine and bit lock mechanism for PCI buses to serialize hotplug operations. For discussions related to previous version, please refer to: http://comments.gmane.org/gmane.linux.kernel.pci/15007 This patch-set is still in early stages, so sending it out just requesting for comments. Any comments are welcomed, especially about whether it's the right/suitable way to solve these race condition issues. patch 1-5: Preparing for coming PCI bus lock patch 6-7: Core of the new PCI bus lock mechanism. patch 8-13: Enhance PCI core to support PCI bus lock mechanism. patch 14-18: Enhance several PCI hotplug drivers to use PCI bus lock to serialize hotplug operations. patch 19-20: Enable PCI bus lock mechanism for x86 and IA64, still need to enable PCI bus lock for other archs. patch 21-22: Cleanups for unsed code. There are multiple methods to trigger PCI hotplug requests/operations concurrently, such as: 1. Sysfs interfaces exported by the PCI core subsystem /sys/devices/pcissss:bb/ssss:bb:dd.f/.../remove /sys/devices/pcissss:bb/ssss:bb:dd.f/.../rescan /sys/devices/pcissss:bb/ssss:bb:dd.f/.../pci_bus/ssss:bb/rescan /sys/bus/pci/rescan 2. Sysfs interfaces exported by the PCI hotplug subsystem /sys/bus/pci/slots/xx/power 3. PCI hotplug events triggered by PCI Hotplug Controllers 4. ACPI hotplug events for PCI host bridges 5. Driver binding/unbinding events binding/unbinding pci drivers with SR-IOV support With current implementation, the PCI core subsystem doesn't support concurrent hotplug operations yet. The existing pci_bus_sem lock only protects several lists in struct pci_bus, such as children list, devices list, but it doesn't protect the pci_bus or pci_dev structure themselves. Let's take pci_remove_bus_device() as an example, which are used by PCI hotplug drivers to hot-remove PCI devices. Currently all these are free running without any protection, so it can't support reentrance. pci_remove_bus_device() ->pci_stop_bus_device() ->pci_stop_bus_device() ->pci_stop_bus_devices() ->pci_stop_dev() Jiang Liu (22): PCI: use pci_get_domain_bus_and_slot() to avoid race conditions PCI: trivial cleanups for drivers/pci/remove.c PCI: change PCI device management code to better follow device model PCI: split PCI bus device registration into two stages PCI: introduce pci_bus_{get|put}() to manage PCI bus reference count PCI: use a global lock to serialize PCI root bridge hotplug operations PCI: introduce PCI bus lock to serialize PCI hotplug operations PCI: introduce hotplug safe search interfaces for PCI bus/device PCI: enhance PCI probe logic to support PCI bus lock mechanism PCI: enhance PCI bus specific logic to support PCI bus lock mechanism PCI: enhance PCI resource assignment logic to support PCI bus lock mechanism PCI: enhance PCI remove logic to support PCI bus lock mechanism PCI: make each PCI device hold a reference to its parent PCI bus PCI/sysfs: use PCI bus lock to avoid race conditions PCI/eeepc: use PCI bus lock to avoid race conditions PCI/asus-wmi: use PCI bus lock to avoid race conditions PCI/pciehp: use PCI bus lock to avoid race conditions PCI/acpiphp: use PCI bus lock to avoid race conditions PCI/x86: enable PCI bus lock mechanism for x86 platforms PCI/IA64: enable PCI bus lock mechanism for IA64 platforms PCI: cleanups for PCI bus lock implementation PCI: unexport pci_root_buses arch/ia64/pci/pci.c | 2 + arch/ia64/sn/kernel/io_common.c | 4 +- arch/ia64/sn/kernel/io_init.c | 1 + arch/ia64/sn/pci/tioca_provider.c | 4 +- arch/x86/pci/acpi.c | 6 +- arch/x86/pci/common.c | 12 +++ drivers/acpi/pci_root.c | 8 +- drivers/edac/i7core_edac.c | 16 ++- drivers/gpu/drm/drm_fops.c | 6 +- drivers/gpu/vga/vgaarb.c | 15 +-- drivers/pci/bus.c | 188 +++++++++++++++++++++++++++++----- drivers/pci/host-bridge.c | 19 ++++ drivers/pci/hotplug/acpiphp_glue.c | 13 ++- drivers/pci/hotplug/cpcihp_generic.c | 8 +- drivers/pci/hotplug/pciehp_pci.c | 15 +++ drivers/pci/hotplug/sgi_hotplug.c | 2 + drivers/pci/iov.c | 11 +- drivers/pci/pci-sysfs.c | 37 ++++--- drivers/pci/probe.c | 83 +++++++++++---- drivers/pci/remove.c | 176 +++++++++++++++++-------------- drivers/pci/search.c | 53 ++++++++-- drivers/pci/setup-bus.c | 65 +++++++++--- drivers/pci/xen-pcifront.c | 10 +- drivers/platform/x86/asus-wmi.c | 23 ++++- drivers/platform/x86/eeepc-laptop.c | 20 ++-- include/linux/pci.h | 56 +++++++++- 26 files changed, 629 insertions(+), 224 deletions(-) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
