snmp: 64bit ipstats_mib for all arches

/proc/net/snmp and /proc/net/netstat expose SNMP counters.

Width of these counters is either 32 or 64 bits, depending on the size
of "unsigned long" in kernel.

This means user program parsing these files must already be prepared to
deal with 64bit values, regardless of user program being 32 or 64 bit.

This patch introduces 64bit snmp values for IPSTAT mib, where some
counters can wrap pretty fast if they are 32bit wide.

# netstat -s|egrep "InOctets|OutOctets"
    InOctets: 244068329096
    OutOctets: 244069348848

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 71 insertions, 4 deletions

diff --git a/include/net/snmp.h b/include/net/snmp.h
index 899003d18db9..a0e61806d480 100644
--- a/include/net/snmp.h
+++ b/include/net/snmp.h
@@ -47,15 +47,16 @@ struct snmp_mib {
 }
 
 /*
- * We use all unsigned longs. Linux will soon be so reliable that even 
- * these will rapidly get too small 8-). Seriously consider the IpInReceives 
- * count on the 20Gb/s + networks people expect in a few years time!
+ * We use unsigned longs for most mibs but u64 for ipstats.
  */
+#include <linux/u64_stats_sync.h>
 
 /* IPstats */
 #define IPSTATS_MIB_MAX __IPSTATS_MIB_MAX
 struct ipstats_mib {
-        unsigned long   mibs[IPSTATS_MIB_MAX];
+        /* mibs[] must be first field of struct ipstats_mib */
+        u64             mibs[IPSTATS_MIB_MAX];
+        struct u64_stats_sync syncp;
 };
 
 /* ICMP */
@@ -155,4 +156,70 @@ struct linux_xfrm_mib {
                 ptr->mibs[basefield##PKTS]++; \
                 ptr->mibs[basefield##OCTETS] += addend;\
         } while (0)
+
+
+#if BITS_PER_LONG==32
+
+#define SNMP_ADD_STATS64_BH(mib, field, addend)                         \
+        do {                                                            \
+                __typeof__(*mib[0]) *ptr = __this_cpu_ptr((mib)[0]);    \
+                u64_stats_update_begin(&ptr->syncp);                    \
+                ptr->mibs[field] += addend;                             \
+                u64_stats_update_end(&ptr->syncp);                      \
+        } while (0)
+#define SNMP_ADD_STATS64_USER(mib, field, addend)                       \
+        do {                                                            \
+                __typeof__(*mib[0]) *ptr;                               \
+                preempt_disable();                                      \
+                ptr = __this_cpu_ptr((mib)[1]);                         \
+                u64_stats_update_begin(&ptr->syncp);                    \
+                ptr->mibs[field] += addend;                             \
+                u64_stats_update_end(&ptr->syncp);                      \
+                preempt_enable();                                       \
+        } while (0)
+#define SNMP_ADD_STATS64(mib, field, addend)                            \
+        do {                                                            \
+                __typeof__(*mib[0]) *ptr;                               \
+                preempt_disable();                                      \
+                ptr = __this_cpu_ptr((mib)[!in_softirq()]);             \
+                u64_stats_update_begin(&ptr->syncp);                    \
+                ptr->mibs[field] += addend;                             \
+                u64_stats_update_end(&ptr->syncp);                      \
+                preempt_enable();                                       \
+        } while (0)
+#define SNMP_INC_STATS64_BH(mib, field) SNMP_ADD_STATS64_BH(mib, field, 1)
+#define SNMP_INC_STATS64_USER(mib, field) SNMP_ADD_STATS64_USER(mib, field, 1)
+#define SNMP_INC_STATS64(mib, field) SNMP_ADD_STATS64(mib, field, 1)
+#define SNMP_UPD_PO_STATS64(mib, basefield, addend)                     \
+        do {                                                            \
+                __typeof__(*mib[0]) *ptr;                               \
+                preempt_disable();                                      \
+                ptr = __this_cpu_ptr((mib)[!in_softirq()]);             \
+                u64_stats_update_begin(&ptr->syncp);                    \
+                ptr->mibs[basefield##PKTS]++;                           \
+                ptr->mibs[basefield##OCTETS] += addend;                 \
+                u64_stats_update_end(&ptr->syncp);                      \
+                preempt_enable();                                       \
+        } while (0)
+#define SNMP_UPD_PO_STATS64_BH(mib, basefield, addend)                  \
+        do {                                                            \
+                __typeof__(*mib[0]) *ptr;                               \
+                ptr = __this_cpu_ptr((mib)[!in_softirq()]);             \
+                u64_stats_update_begin(&ptr->syncp);                    \
+                ptr->mibs[basefield##PKTS]++;                           \
+                ptr->mibs[basefield##OCTETS] += addend;                 \
+                u64_stats_update_end(&ptr->syncp);                      \
+        } while (0)
+#else
+#define SNMP_INC_STATS64_BH(mib, field)         SNMP_INC_STATS_BH(mib, field)
+#define SNMP_INC_STATS64_USER(mib, field)       SNMP_INC_STATS_USER(mib, field)
+#define SNMP_INC_STATS64(mib, field)            SNMP_INC_STATS(mib, field)
+#define SNMP_DEC_STATS64(mib, field)            SNMP_DEC_STATS(mib, field)
+#define SNMP_ADD_STATS64_BH(mib, field, addend) SNMP_ADD_STATS_BH(mib, field, addend)
+#define SNMP_ADD_STATS64_USER(mib, field, addend) SNMP_ADD_STATS_USER(mib, field, addend)
+#define SNMP_ADD_STATS64(mib, field, addend)    SNMP_ADD_STATS(mib, field, addend)
+#define SNMP_UPD_PO_STATS64(mib, basefield, addend) SNMP_UPD_PO_STATS(mib, basefield, addend)
+#define SNMP_UPD_PO_STATS64_BH(mib, basefield, addend) SNMP_UPD_PO_STATS_BH(mib, basefield, addend)
+#endif
+
 #endif