diff options
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 6cc8a70350ac..a76021c71207 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3993,6 +3993,45 @@ static int __init netdev_dma_register(void) static int __init netdev_dma_register(void) { return -ENODEV; } #endif /* CONFIG_NET_DMA */ +/** + * netdev_compute_feature - compute conjunction of two feature sets + * @all: first feature set + * @one: second feature set + * + * Computes a new feature set after adding a device with feature set + * @one to the master device with current feature set @all. Returns + * the new feature set. + */ +int netdev_compute_features(unsigned long all, unsigned long one) +{ + /* if device needs checksumming, downgrade to hw checksumming */ + if (all & NETIF_F_NO_CSUM && !(one & NETIF_F_NO_CSUM)) + all ^= NETIF_F_NO_CSUM | NETIF_F_HW_CSUM; + + /* if device can't do all checksum, downgrade to ipv4/ipv6 */ + if (all & NETIF_F_HW_CSUM && !(one & NETIF_F_HW_CSUM)) + all ^= NETIF_F_HW_CSUM + | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM; + + if (one & NETIF_F_GSO) + one |= NETIF_F_GSO_SOFTWARE; + one |= NETIF_F_GSO; + + /* If even one device supports robust GSO, enable it for all. */ + if (one & NETIF_F_GSO_ROBUST) + all |= NETIF_F_GSO_ROBUST; + + all &= one | NETIF_F_LLTX; + + if (!(all & NETIF_F_ALL_CSUM)) + all &= ~NETIF_F_SG; + if (!(all & NETIF_F_SG)) + all &= ~NETIF_F_GSO_MASK; + + return all; +} +EXPORT_SYMBOL(netdev_compute_features); + /* * Initialize the DEV module. At boot time this walks the device list and * unhooks any devices that fail to initialise (normally hardware not |