From 118de6106735cfeb04daf9de1d5a9f953ac034ba Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 3 Jun 2021 10:34:10 -0700 Subject: net: ethernet: rmnet: Restructure if checks to avoid uninitialized warning Clang warns that proto in rmnet_map_v5_checksum_uplink_packet() might be used uninitialized: drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:283:14: warning: variable 'proto' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] } else if (skb->protocol == htons(ETH_P_IPV6)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:295:36: note: uninitialized use occurs here check = rmnet_map_get_csum_field(proto, trans); ^~~~~ drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:283:10: note: remove the 'if' if its condition is always true } else if (skb->protocol == htons(ETH_P_IPV6)) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:270:11: note: initialize the variable 'proto' to silence this warning u8 proto; ^ = '\0' 1 warning generated. This is technically a false positive because there is an if statement above this one that checks skb->protocol for not being either ETH_P_IP{,V6}. However, it is more obvious to sink that into the if statement as an else branch, which makes the code clearer and fixes the warning. At the same time, move the "IS_ENABLED(CONFIG_IPV6)" into the else if condition so that the else branch of the preprocessor conditional can be shared, since there is no build failure with CONFIG_IPV6 disabled. Fixes: b6e5d27e32ef ("net: ethernet: rmnet: Add support for MAPv5 egress packets") Link: https://github.com/ClangBuiltLinux/linux/issues/1390 Signed-off-by: Nathan Chancellor Signed-off-by: David S. Miller --- drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index 6492ec5bdec4..cecf72be5102 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -269,27 +269,20 @@ static void rmnet_map_v5_checksum_uplink_packet(struct sk_buff *skb, void *trans; u8 proto; - if (skb->protocol != htons(ETH_P_IP) && - skb->protocol != htons(ETH_P_IPV6)) { - priv->stats.csum_err_invalid_ip_version++; - goto sw_csum; - } - if (skb->protocol == htons(ETH_P_IP)) { u16 ip_len = ((struct iphdr *)iph)->ihl * 4; proto = ((struct iphdr *)iph)->protocol; trans = iph + ip_len; - } else if (skb->protocol == htons(ETH_P_IPV6)) { -#if IS_ENABLED(CONFIG_IPV6) + } else if (IS_ENABLED(CONFIG_IPV6) && + skb->protocol == htons(ETH_P_IPV6)) { u16 ip_len = sizeof(struct ipv6hdr); proto = ((struct ipv6hdr *)iph)->nexthdr; trans = iph + ip_len; -#else + } else { priv->stats.csum_err_invalid_ip_version++; goto sw_csum; -#endif /* CONFIG_IPV6 */ } check = rmnet_map_get_csum_field(proto, trans); -- cgit v1.2.3