[libvirt] [PATCH] qemu: Rollback on used USB devices
One of our latest USB device handling patches 05abd1507d66aabb6cad12eeafeb4c4d1911c585 introduced a regression. That is, we first create a temporary list of all USB devices that are to be used by domain just starting up. Then we iterate over and check if a device from the list is in the global list of currently assigned devices (activeUsbHostdevs). If not, we add it there and continue with next iteration then. But if a device from temporary list is either taken already or adding to the activeUsbHostdevs fails, we remove all devices in temp list from the activeUsbHostdevs list. Therefore, if a device is already taken we remove it from activeUsbHostdevs even if we should not. Thus, next time we allow the device to be assigned to another domain. --- src/qemu/qemu_hostdev.c | 28 ++++++++++++---------------- 1 files changed, 12 insertions(+), 16 deletions(-) diff --git a/src/qemu/qemu_hostdev.c b/src/qemu/qemu_hostdev.c index b649ae0..ff13305 100644 --- a/src/qemu/qemu_hostdev.c +++ b/src/qemu/qemu_hostdev.c @@ -567,7 +567,7 @@ qemuPrepareHostdevUSBDevices(struct qemud_driver *driver, const char *name, usbDeviceList *list) { - int i; + int i, j; unsigned int count; usbDevice *tmp; @@ -586,7 +586,7 @@ qemuPrepareHostdevUSBDevices(struct qemud_driver *driver, qemuReportError(VIR_ERR_OPERATION_INVALID, _("USB device %s is already in use"), usbDeviceGetName(tmp)); - return -1; + goto error; } usbDeviceSetUsedBy(usb, name); @@ -598,9 +598,16 @@ qemuPrepareHostdevUSBDevices(struct qemud_driver *driver, * perform rollback on failure. */ if (usbDeviceListAdd(driver->activeUsbHostdevs, usb) < 0) - return -1; + goto error; } return 0; + +error: + for (j = 0; j < i; j++) { + tmp = usbDeviceListGet(list, i); + usbDeviceListSteal(driver->activeUsbHostdevs, tmp); + } + return -1; } static int @@ -621,8 +628,7 @@ qemuPrepareHostUSBDevices(struct qemud_driver *driver, if (!(list = usbDeviceListNew())) goto cleanup; - /* Loop 1: build temporary list and validate no usb device - * is already taken + /* Loop 1: build temporary list */ for (i = 0 ; i < nhostdevs ; i++) { virDomainHostdevDefPtr hostdev = hostdevs[i]; @@ -678,7 +684,7 @@ qemuPrepareHostUSBDevices(struct qemud_driver *driver, * wrong, perform rollback. */ if (qemuPrepareHostdevUSBDevices(driver, def->name, list) < 0) - goto inactivedevs; + goto cleanup; /* Loop 2: Temporary list was successfully merged with * driver list, so steal all items to avoid freeing them @@ -690,16 +696,6 @@ qemuPrepareHostUSBDevices(struct qemud_driver *driver, } ret = 0; - goto cleanup; - -inactivedevs: - /* Steal devices from driver->activeUsbHostdevs. - * We will free them later. - */ - for (i = 0; i < usbDeviceListCount(list); i++) { - tmp = usbDeviceListGet(list, i); - usbDeviceListSteal(driver->activeUsbHostdevs, tmp); - } cleanup: usbDeviceListFree(list); -- 1.7.8.5
On 05/16/2012 08:53 AM, Michal Privoznik wrote:
One of our latest USB device handling patches 05abd1507d66aabb6cad12eeafeb4c4d1911c585 introduced a regression. That is, we first create a temporary list of all USB devices that are to be used by domain just starting up. Then we iterate over and check if a device from the list is in the global list of currently assigned devices (activeUsbHostdevs). If not, we add it there and continue with next iteration then. But if a device from temporary list is either taken already or adding to the activeUsbHostdevs fails, we remove all devices in temp list from the activeUsbHostdevs list. Therefore, if a device is already taken we remove it from activeUsbHostdevs even if we should not. Thus, next time we allow the device to be assigned to another domain.
My bad for not reviewing the original patch in context in the first place, or I might have questioned the loop consolidation.
--- src/qemu/qemu_hostdev.c | 28 ++++++++++++---------------- 1 files changed, 12 insertions(+), 16 deletions(-)
ACK. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
On 16.05.2012 17:06, Eric Blake wrote:
On 05/16/2012 08:53 AM, Michal Privoznik wrote:
One of our latest USB device handling patches 05abd1507d66aabb6cad12eeafeb4c4d1911c585 introduced a regression. That is, we first create a temporary list of all USB devices that are to be used by domain just starting up. Then we iterate over and check if a device from the list is in the global list of currently assigned devices (activeUsbHostdevs). If not, we add it there and continue with next iteration then. But if a device from temporary list is either taken already or adding to the activeUsbHostdevs fails, we remove all devices in temp list from the activeUsbHostdevs list. Therefore, if a device is already taken we remove it from activeUsbHostdevs even if we should not. Thus, next time we allow the device to be assigned to another domain.
My bad for not reviewing the original patch in context in the first place, or I might have questioned the loop consolidation.
I could have spotted this as well. So don't blame yourself.
--- src/qemu/qemu_hostdev.c | 28 ++++++++++++---------------- 1 files changed, 12 insertions(+), 16 deletions(-)
ACK.
Thanks, pushed. Michal
participants (2)
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Eric Blake -
Michal Privoznik