net: avoid reloads in SNMP_UPD_PO_STATS

Avoid two instructions to reload dev->nd_net->mib.ip_statistics pointer,
unsing a temp variable, in ip_rcv(), ip_output() paths for example.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/snmp.h b/include/net/snmp.h
index 0147b901e79c4d6b43eef9dbe45f76eef0fc1720..71596261fa997ec7014b77f0bbee9b47b6146493 100644 (file)
--- a/include/net/snmp.h
+++ b/include/net/snmp.h
@@ -154,13 +154,15 @@ struct linux_xfrm_mib {
  */
 #define SNMP_UPD_PO_STATS(mib, basefield, addend)      \
        do { \
-               this_cpu_inc(mib[0]->mibs[basefield##PKTS]);            \
-               this_cpu_add(mib[0]->mibs[basefield##OCTETS], addend);  \
+               __typeof__(*mib[0]->mibs) *ptr = mib[0]->mibs;  \
+               this_cpu_inc(ptr[basefield##PKTS]);             \
+               this_cpu_add(ptr[basefield##OCTETS], addend);   \
        } while (0)
 #define SNMP_UPD_PO_STATS_BH(mib, basefield, addend)   \
        do { \
-               __this_cpu_inc(mib[0]->mibs[basefield##PKTS]);          \
-               __this_cpu_add(mib[0]->mibs[basefield##OCTETS], addend);        \
+               __typeof__(*mib[0]->mibs) *ptr = mib[0]->mibs;  \
+               __this_cpu_inc(ptr[basefield##PKTS]);           \
+               __this_cpu_add(ptr[basefield##OCTETS], addend); \
        } while (0)