net: snmp: fix 64bit stats on 32bit arches

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/snmp.h b/include/net/snmp.h
index 6bdd255b22506b755410b625d5c76ae70dde0eb6..c9228ad7ee91865cbeff19328e219171dd62b456 100644 (file)
--- 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)