Re: [libvirt] [PATCH] qemu: Avoid holding the driver lock in trivial snapshot API's

In most of the snapshot API's there's no need to hold the driver lock the whole time. This patch adds helper functions that get the domain object in functions that don't require the driver lock and simplifies call paths from snapshot-related API's. --- src/conf/domain_conf.c | 3 +- src/qemu/qemu_driver.c | 306 +++++++++++++++---------------------------------- 2 files changed, 94 insertions(+), 215 deletions(-)

void virDomainObjUnlock(virDomainObjPtr obj) { - virMutexUnlock(&obj->lock); + if (obj) + virMutexUnlock(&obj->lock); }

+/* Looks up the domain obj and unlocks the driver */ +static virDomainObjPtr +qemuDomObjFromDomain(virDomainPtr domain) +{ + struct qemud_driver *driver = domain->conn->privateData; + virDomainObjPtr vm; + char uuidstr[VIR_UUID_STRING_BUFLEN]; + + qemuDriverLock(driver); + vm = virDomainFindByUUID(&driver->domains, domain->uuid); + qemuDriverUnlock(driver); + if (!vm) { + virUUIDFormat(domain->uuid, uuidstr); + virReportError(VIR_ERR_NO_DOMAIN, + _("no domain with matching uuid '%s'"), uuidstr); + } + + return vm; +}

@@ -11305,59 +11359,39 @@ static int qemuDomainSnapshotListNames(virDomainPtr domain, char **names, int nameslen, unsigned int flags) { - struct qemud_driver *driver = domain->conn->privateData; virDomainObjPtr vm = NULL; int n = -1; virCheckFlags(VIR_DOMAIN_SNAPSHOT_LIST_ROOTS | VIR_DOMAIN_SNAPSHOT_FILTERS_ALL, -1); - qemuDriverLock(driver); - vm = virDomainFindByUUID(&driver->domains, domain->uuid); - if (!vm) { - char uuidstr[VIR_UUID_STRING_BUFLEN]; - virUUIDFormat(domain->uuid, uuidstr); - virReportError(VIR_ERR_NO_DOMAIN, - _("no domain with matching uuid '%s'"), uuidstr); + if (!(vm = qemuDomObjFromDomain(domain))) goto cleanup; - }

n = virDomainSnapshotObjListGetNames(vm->snapshots, NULL, names, nameslen, flags); cleanup: - if (vm) - virDomainObjUnlock(vm); - qemuDriverUnlock(driver); + virDomainObjUnlock(vm); return n;