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>

1 files changed, 6 insertions, 4 deletions

diff --git a/include/net/snmp.h b/include/net/snmp.h
index 0147b901e79c..71596261fa99 100644
--- 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)