Hotplug CallTrace: int acpiphp_enable_slot(struct acpiphp_slot *slot) _enable_device(slot); _pci_bus_add_devices(bus); # un-added new devs(all funcs in slot) will be added list_for_each_entry(dev, &bus->devices, bus_list) { if (dev->is_added) continue; pci_bus_add_device(dev); device_add(&dev->dev); dev->is_added = 1;
'dev->is_added' is used to trace if pci dev is added to bus, all funcs in same slot would be added to bus in enable_device(slot). So we need to clean all funcs of same slot in disable_device(slot).
But hot-remove exists bug: https://bugzilla.kernel.org/show_bug.cgi?id=43219 (dmesg and DSDT were attached in bz), detail:
. Boot up a Linux VM with 8 pci block devices which are the 8 functions in one pci slot. | # qemu-kvm ... | -drive file=images/u0,if=none,id=drv0,format=qcow2,cache=none \ | -device virtio-blk-pci,drive=drv0,id=v0,multifunction=on,addr=0x03.0 \ | .... | -drive file=images/u7,if=none,id=drv7,format=qcow2,cache=none \ | -device virtio-blk-pci,drive=drv7,id=v7,multifunction=on,addr=0x03.7 \
. Check devices in guest. | vm)# ls /dev/vd* | vda vdb vdc vde vdf vdg vdh | vm)# lspci |grep block | 00:03.0 SCSI storage controller: Red Hat, Inc Virtio block device | ... | 00:03.7 SCSI storage controller: Red Hat, Inc Virtio block device |
. Func1~7 still exist in guest after hot-removing the whole slot by qemu monitor cmd. | vm)# lspci |grep block (00:03.0 disappeared) | 00:03.1 SCSI storage controller: Red Hat, Inc Virtio block device (rev ff) | ... | 00:03.7 SCSI storage controller: Red Hat, Inc Virtio block device (rev ff) | vm)# ls /dev/vd* (vda disappeared) | vdb vdc vde vdf vdg vdh | vm)# mkfs /dev/vdb | INFO: task mkfs.ext2:1784 blocked for more than 120 seconds.
We process pci slot as a whole device in pciphp spec, seabios only defines one device for a slot in ACPI DSDT table. In acpiphp_glue.c:register_slot(), only one entry is added (for func#0) into 'slot->funcs' list. When we release the whole slot, only the entry in 'slot->funcs' will be cleaned, so func#1~7 could not be cleaned from system.
| drivers/pci/hotplug/acpiphp_glue.c: | static int disable_device(struct acpiphp_slot *slot) { | list_for_each_entry(func, &slot->funcs, sibling) { | pdev = pci_get_slot(slot->bridge->pci_bus, | PCI_DEVFN(slot->device, func->function)); | ..clean code.. // those code is only executed 1 time(for func#0) | __pci_remove_bus_device(pdev); | pci_dev_put(pdev);
Hotpluging multifunc of guests(WinXp/Win7) is fine.
--- v1 thread: http://marc.info/?t=131597601700003&r=1&w=2
Changes from v1: - rebase patch to latest linux.git - remove unnecessary multiplefunction check - rename 'i' to meaningful 'fn' - fix coding style
Changes from v2: - update detail reason(calltrace) to commitlog - remove hardcode 8, find funcs in pci devlist
Signed-off-by: Amos Kong akong@redhat.com --- drivers/pci/hotplug/acpiphp_glue.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index 806c44f..a7442d9 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -885,7 +885,7 @@ static void disable_bridges(struct pci_bus *bus) static int disable_device(struct acpiphp_slot *slot) { struct acpiphp_func *func; - struct pci_dev *pdev; + struct pci_dev *pdev, *tmp; struct pci_bus *bus = slot->bridge->pci_bus;
/* The slot will be enabled when func 0 is added, so check @@ -902,9 +902,10 @@ static int disable_device(struct acpiphp_slot *slot) func->bridge = NULL; }
- pdev = pci_get_slot(slot->bridge->pci_bus, - PCI_DEVFN(slot->device, func->function)); - if (pdev) { + list_for_each_entry_safe(pdev, tmp, &bus->devices, bus_list) { + if (PCI_SLOT(pdev->devfn) != slot->device) + continue; + pci_stop_bus_device(pdev); if (pdev->subordinate) { disable_bridges(pdev->subordinate);