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[net-next] net: snmp: fix 64bit stats on 32bit arches

Message ID 1461850404.5535.103.camel@edumazet-glaptop3.roam.corp.google.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Eric Dumazet April 28, 2016, 1:33 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

I accidentally replaced BH disabling by preemption disabling
in SNMP_ADD_STATS64() and SNMP_UPD_PO_STATS64() on 32bit builds.

For 64bit stats on 32bit arch, we really need to disable BH,
since the "struct u64_stats_sync syncp" might be manipulated
both from process and BH contexts.

Fixes: 6aef70a851ac ("net: snmp: kill various STATS_USER() helpers")
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/snmp.h |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

David Miller April 28, 2016, 3:55 p.m. UTC | #1 
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 28 Apr 2016 06:33:24 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> I accidentally replaced BH disabling by preemption disabling
> in SNMP_ADD_STATS64() and SNMP_UPD_PO_STATS64() on 32bit builds.
> 
> For 64bit stats on 32bit arch, we really need to disable BH,
> since the "struct u64_stats_sync syncp" might be manipulated
> both from process and BH contexts.
> 
> Fixes: 6aef70a851ac ("net: snmp: kill various STATS_USER() helpers")
> Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied.
diff mbox

Patch

diff --git a/include/net/snmp.h b/include/net/snmp.h
index 6bdd255b2250..c9228ad7ee91 100644
--- a/include/net/snmp.h
+++ b/include/net/snmp.h
@@ -166,9 +166,9 @@  struct linux_xfrm_mib {
 
 #define SNMP_ADD_STATS64(mib, field, addend) 				\
 	do {								\
-		preempt_disable();					\
+		local_bh_disable();					\
 		__SNMP_ADD_STATS64(mib, field, addend);			\
-		preempt_enable();					\
+		local_bh_enable();				\
 	} while (0)
 
 #define __SNMP_INC_STATS64(mib, field) SNMP_ADD_STATS64(mib, field, 1)
@@ -184,9 +184,9 @@  struct linux_xfrm_mib {
 	} while (0)
 #define SNMP_UPD_PO_STATS64(mib, basefield, addend)			\
 	do {								\
-		preempt_disable();					\
+		local_bh_disable();					\
 		__SNMP_UPD_PO_STATS64(mib, basefield, addend);		\
-		preempt_enable();					\
+		local_bh_enable();				\
 	} while (0)
 #else
 #define __SNMP_INC_STATS64(mib, field)		__SNMP_INC_STATS(mib, field)