netdev - [PATCH] net: avoid reloads in SNMP_UPD_PO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1344147973.9299.1563.camel@edumazet-glaptop>
Date:	Sun, 05 Aug 2012 08:26:13 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev <netdev@...r.kernel.org>
Subject: [PATCH] net: avoid reloads in SNMP_UPD_PO_STATS

From: Eric Dumazet <edumazet@...gle.com>

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@...gle.com>
---
 include/net/snmp.h |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/net/snmp.h b/include/net/snmp.h
index 0147b90..7159626 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)
 
 


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html