[CASSINI]: Fix endianness bug.

Here's proposed fix for RX checksum handling in cassini; it affects
little-endian working with half-duplex gigabit, but obviously needs
testing on big-endian too.

The problem is, we need to convert checksum to fixed-endian *before*
correcting for (unstripped) FCS.  On big-endian it won't matter
(conversion is no-op), on little-endian it will, but only if FCS is
not stripped by hardware; i.e. in half-duplex gigabit mode when
->crc_size is set.

cassini.c part is that fix, cassini.h one consists of trivial
endianness annotations.  With that applied the sucker is endian-clean,
according to sparse.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/net/cassini.c b/drivers/net/cassini.c
index 7df31b5561cc..9030ca54a5bd 100644
--- a/drivers/net/cassini.c
+++ b/drivers/net/cassini.c
@@ -1979,6 +1979,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
         struct cas_page *page;
         struct sk_buff *skb;
         void *addr, *crcaddr;
+        __sum16 csum;
         char *p;
 
         hlen = CAS_VAL(RX_COMP2_HDR_SIZE, words[1]);
@@ -2158,14 +2159,15 @@ end_copy_pkt:
                 skb_put(skb, alloclen);
         }
 
-        i = CAS_VAL(RX_COMP4_TCP_CSUM, words[3]);
+        csum = (__force __sum16)htons(CAS_VAL(RX_COMP4_TCP_CSUM, words[3]));
         if (cp->crc_size) {
                 /* checksum includes FCS. strip it out. */
-                i = csum_fold(csum_partial(crcaddr, cp->crc_size, i));
+                csum = csum_fold(csum_partial(crcaddr, cp->crc_size,
+                                              csum_unfold(csum)));
                 if (addr)
                         cas_page_unmap(addr);
         }
-        skb->csum = ntohs(i ^ 0xffff);
+        skb->csum = csum_unfold(~csum);
         skb->ip_summed = CHECKSUM_COMPLETE;
         skb->protocol = eth_type_trans(skb, cp->dev);
         return len;