Re: [libvirt] [PATCHv2] util: keep/use a bitmap of in-use macvtap devices

This patch creates two bitmaps, one for macvlan devicenames and one

diff --git a/src/util/virnetdevmacvlan.c b/src/util/virnetdevmacvlan.c

+/** + * virNetDevMacVLanReserveName: + * + * @name: already-known name of device + * @quietFail: don't log an error if this name is already in-use + * + * Extract the device type and id from a macvtap/macvlan device name + * and mark the appropriate position as in-use in the appropriate + * bitmap. + * + * returns 0 on success, -1 on failure, -2 if the name doesn't fit the auto-pattern

+ */ +int +virNetDevMacVLanReserveName(const char *name, bool quietFail) +{ + unsigned int id; + unsigned int flags = 0; + const char *idstr = NULL; + + if (virNetDevMacVLanInitialize() < 0) + return -1; + + if (STRPREFIX(name, MACVTAP_NAME_PREFIX)) { + idstr = name + strlen(MACVTAP_NAME_PREFIX); + flags |= VIR_NETDEV_MACVLAN_CREATE_WITH_TAP; + } else if (STRPREFIX(name, MACVLAN_NAME_PREFIX)) { + idstr = name + strlen(MACVLAN_NAME_PREFIX); + } else { + return -2; + } + + if (virStrToLong_ui(idstr, NULL, 10, &id) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("couldn't get id value from macvtap device name %s"), + name); + return -1; + } + return virNetDevMacVLanReserveID(id, flags, quietFail, false); +}

const char *type = (flags & VIR_NETDEV_MACVLAN_CREATE_WITH_TAP) ? "macvtap" : "macvlan"; - const char *prefix = (flags & VIR_NETDEV_MACVLAN_CREATE_WITH_TAP) ? - MACVTAP_NAME_PREFIX : MACVLAN_NAME_PREFIX;

const char *pattern = (flags & VIR_NETDEV_MACVLAN_CREATE_WITH_TAP) ? MACVTAP_NAME_PATTERN : MACVLAN_NAME_PATTERN; - int c, rc; + int rc, reservedID = -1; char ifname[IFNAMSIZ]; int retries, do_retry = 0; uint32_t macvtapMode; - const char *cr_ifname = NULL; + const char *ifnameCreated = NULL; int ret; int vf = -1; bool vnet_hdr = flags & VIR_NETDEV_MACVLAN_VNET_HDR;

+ retries = MACVLAN_MAX_ID + 1; + while (!ifnameCreated && retries) { virMutexLock(&virNetDevMacVLanCreateMutex); - for (c = 0; c < 8192; c++) { - snprintf(ifname, sizeof(ifname), pattern, c); - if ((ret = virNetDevExists(ifname)) < 0) { - virMutexUnlock(&virNetDevMacVLanCreateMutex); + reservedID = virNetDevMacVLanReserveID(reservedID, flags, false, true); + if (reservedID < 0) { + virMutexUnlock(&virNetDevMacVLanCreateMutex); + return -1; + } + snprintf(ifname, sizeof(ifname), pattern, reservedID);