Re: [libvirt] [PATCHv3 06/11] util: Learn virNetDevTapCreate multiqueue network

On 05/16/2013 08:49 AM, Michal Privoznik wrote: "array of file descriptors ..." "number of file descriptors in @tapfd" > * @flags: OR of virNetDevTapCreateFlags. Only one flag is recognized: > * > * VIR_NETDEV_TAP_CREATE_VNET_HDR > @@ -148,76 +149,85 @@ virNetDevProbeVnetHdr(int tapfd) > * VIR_NETDEV_TAP_CREATE_PERSIST > * - The device will persist after the file descriptor is closed > * > - * Creates a tap interface. > - * If the @tapfd parameter is supplied, the open tap device file descriptor > - * will be returned, otherwise the TAP device will be closed. The caller must > - * use virNetDevTapDelete to remove a persistent TAP device when it is no > - * longer needed. > + * Creates a tap interface. The caller must use virNetDevTapDelete to > + * remove a persistent TAP device when it is no longer needed. In case > + * @tapfdSize is greater than one, multiqueue extension is requested > + * from kernel. > * > * Returns 0 in case of success or -1 on failure. > */ > int virNetDevTapCreate(char **ifname, > int *tapfd, > + int tapfdSize, > unsigned int flags) > { > - int fd; > + int i; > struct ifreq ifr; > int ret = -1; > - > - if ((fd = open("/dev/net/tun", O_RDWR)) < 0) { > - virReportSystemError(errno, "%s", > - _("Unable to open /dev/net/tun, is tun module loaded?")); > - return -1; > - } > + int fd; > > memset(&ifr, 0, sizeof(ifr)); > + for (i = 0; i < tapfdSize; i++) { > + if ((fd = open("/dev/net/tun", O_RDWR)) < 0) { > + virReportSystemError(errno, "%s", > + _("Unable to open /dev/net/tun, is tun module loaded?")); > + goto cleanup; > + } > > - ifr.ifr_flags = IFF_TAP|IFF_NO_PI; > + memset(&ifr, 0, sizeof(ifr)); > + > + ifr.ifr_flags = IFF_TAP | IFF_NO_PI; > + /* If tapfdSize is greater than one, request multiqueue */ > + if (tapfdSize > 1) > + ifr.ifr_flags |= IFF_MULTI_QUEUE; > > # ifdef IFF_VNET_HDR > - if ((flags & VIR_NETDEV_TAP_CREATE_VNET_HDR) && > - virNetDevProbeVnetHdr(fd)) > - ifr.ifr_flags |= IFF_VNET_HDR; > + if ((flags & VIR_NETDEV_TAP_CREATE_VNET_HDR) && > + virNetDevProbeVnetHdr(fd)) > + ifr.ifr_flags |= IFF_VNET_HDR; > # endif > > - if (virStrcpyStatic(ifr.ifr_name, *ifname) == NULL) { > - virReportSystemError(ERANGE, > - _("Network interface name '%s' is too long"), > - *ifname); > - goto cleanup; > + if (virStrcpyStatic(ifr.ifr_name, *ifname) == NULL) { > + virReportSystemError(ERANGE, > + _("Network interface name '%s' is too long"), > + *ifname); > + goto cleanup; > > - } > + } > > - if (ioctl(fd, TUNSETIFF, &ifr) < 0) { > - virReportSystemError(errno, > - _("Unable to create tap device %s"), > - NULLSTR(*ifname)); > - goto cleanup; > - } > + if (ioctl(fd, TUNSETIFF, &ifr) < 0) { > + virReportSystemError(errno, > + _("Unable to create tap device %s"), > + NULLSTR(*ifname)); > + goto cleanup; > + } > > - if ((flags & VIR_NETDEV_TAP_CREATE_PERSIST) && > - (errno = ioctl(fd, TUNSETPERSIST, 1))) { > - virReportSystemError(errno, > - _("Unable to set tap device %s to persistent"), > - NULLSTR(*ifname)); > - goto cleanup; > - } > + if (i == 0) { > + /* In case we are looping more than once, set other > + * TAPs to have the same name */ > + VIR_FREE(*ifname); > + if (ifr.ifr_name && VIR_STRDUP(*ifname, ifr.ifr_name) < 0) > + goto cleanup; > + } > > - VIR_FREE(*ifname); > - if (!(*ifname = strdup(ifr.ifr_name))) { > - virReportOOMError(); > - goto cleanup; > + if ((flags & VIR_NETDEV_TAP_CREATE_PERSIST) && > + (errno = ioctl(fd, TUNSETPERSIST, 1))) { > + virReportSystemError(errno, > + _("Unable to set tap device %s to persistent"), > + NULLSTR(*ifname)); > + goto cleanup; > + } > + tapfd[i] = fd; > } > - if (tapfd) > - *tapfd = fd; > - else > - VIR_FORCE_CLOSE(fd); > > ret = 0; > > cleanup: > - if (ret < 0) > + if (ret < 0) { > VIR_FORCE_CLOSE(fd); > + while (i--) > + VIR_FORCE_CLOSE(tapfd[i]); > + } > > return ret; > } > @@ -266,6 +276,7 @@ cleanup: > #else /* ! TUNSETIFF */ > int virNetDevTapCreate(char **ifname ATTRIBUTE_UNUSED, > int *tapfd ATTRIBUTE_UNUSED, > + int tapfdSize ATTRIBUTE_UNUSED, > unsigned int flags ATTRIBUTE_UNUSED) > { > virReportSystemError(ENOSYS, "%s", > @@ -286,7 +297,8 @@ int virNetDevTapDelete(const char *ifname ATTRIBUTE_UNUSED) > * @brname: the bridge name > * @ifname: the interface name (or name template) > * @macaddr: desired MAC address > - * @tapfd: file descriptor return value for the new tap device > + * @tapfd: array of file descriptor return value for the new tap device "number of file descriptors in @tapfd" ACK with comment fixes.