Re: [PATCH net 2/2] net: systemport: Fix sparse warnings in bcm_sysport_insert_tsb()

[Sasha Levin]

Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag,
fixing commit: 80105befdb4b net: systemport: add Broadcom SYSTEMPORT Ethernet 
MAC driver.

The bot has also determined it's probably a bug fixing patch. (score: 50.4075)

The bot has tested the following trees: v4.16, v4.15.15, v4.14.32, v4.9.92, 
v4.4.126.

v4.16: Build OK!
v4.15.15: Build OK!
v4.14.32: Build OK!
v4.9.92: Build OK!
v4.4.126: Build OK!

--
Thanks,
Sasha

Re: [PATCH net 2/2] net: systemport: Fix sparse warnings in bcm_sysport_insert_tsb()

[Al Viro]

On Mon, Apr 02, 2018 at 03:58:56PM -0700, Florian Fainelli wrote:
> skb->protocol is a __be16 which we would be calling htons() against,
> while this is not wrong per-se as it correctly results in swapping the
> value on LE hosts, this still upsets sparse. Adopt a similar pattern to
> what other drivers do and just assign ip_ver to skb->protocol, and then
> use htons() against the different constants such that the compiler can
> resolve the values at build time.

This is completely bogus.  What sparse is complaining about is htons used
to convert from big-endian to host-endian.  Which is what ntohs is for.
IOW, instead of all that crap just

-   ip_ver = htons(skb->protocol);
+   ip_ver = ntohs(skb->protocol);

and be done with that.  Same in other drivers with the same problem.

[PATCH net 2/2] net: systemport: Fix sparse warnings in bcm_sysport_insert_tsb()

[Florian Fainelli]

skb->protocol is a __be16 which we would be calling htons() against,
while this is not wrong per-se as it correctly results in swapping the
value on LE hosts, this still upsets sparse. Adopt a similar pattern to
what other drivers do and just assign ip_ver to skb->protocol, and then
use htons() against the different constants such that the compiler can
resolve the values at build time.

Fixes: 80105befdb4b ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC 
driver")
Signed-off-by: Florian Fainelli 
---
 drivers/net/ethernet/broadcom/bcmsysport.c | 11 ++-
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c 
b/drivers/net/ethernet/broadcom/bcmsysport.c
index 3fc549b88c43..879db1c700bd 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -1133,7 +1133,7 @@ static struct sk_buff *bcm_sysport_insert_tsb(struct 
sk_buff *skb,
u32 csum_info;
u8 ip_proto;
u16 csum_start;
-   u16 ip_ver;
+   __be16 ip_ver;
 
/* Re-allocate SKB if needed */
if (unlikely(skb_headroom(skb) < sizeof(*tsb))) {
@@ -1152,12 +1152,12 @@ static struct sk_buff *bcm_sysport_insert_tsb(struct 
sk_buff *skb,
memset(tsb, 0, sizeof(*tsb));
 
if (skb->ip_summed == CHECKSUM_PARTIAL) {
-   ip_ver = htons(skb->protocol);
+   ip_ver = skb->protocol;
switch (ip_ver) {
-   case ETH_P_IP:
+   case htons(ETH_P_IP):
ip_proto = ip_hdr(skb)->protocol;
break;
-   case ETH_P_IPV6:
+   case htons(ETH_P_IPV6):
ip_proto = ipv6_hdr(skb)->nexthdr;
break;
default:
@@ -1171,7 +1171,8 @@ static struct sk_buff *bcm_sysport_insert_tsb(struct 
sk_buff *skb,
 
if (ip_proto == IPPROTO_TCP || ip_proto == IPPROTO_UDP) {
csum_info |= L4_LENGTH_VALID;
-   if (ip_proto == IPPROTO_UDP && ip_ver == ETH_P_IP)
+   if (ip_proto == IPPROTO_UDP &&
+   ip_ver == htons(ETH_P_IP))
csum_info |= L4_UDP;
} else {
csum_info = 0;
-- 
2.14.1