net: clean up snmp stats code

commit 8f0ea0fe3a036a47767f9c80e (snmp: reduce percpu needs by 50%)
reduced snmp array size to 1, so technically it doesn't have to be
an array any more. What's more, after the following commit:

	commit 933393f58fef9963eac61db8093689544e29a600
	Date:   Thu Dec 22 11:58:51 2011 -0600

	    percpu: Remove irqsafe_cpu_xxx variants

	    We simply say that regular this_cpu use must be safe regardless of
	    preemption and interrupt state.  That has no material change for x86
	    and s390 implementations of this_cpu operations.  However, arches that
	    do not provide their own implementation for this_cpu operations will
	    now get code generated that disables interrupts instead of preemption.

probably no arch wants to have SNMP_ARRAY_SZ == 2. At least after
almost 3 years, no one complains.

So, just convert the array to a single pointer and remove snmp_mib_init()
and snmp_mib_free() as well.

Cc: Christoph Lameter <cl@linux.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 18 insertions, 32 deletions

diff --git a/include/net/ip.h b/include/net/ip.h
index 1988cefdbb70..16146b667ddb 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -196,27 +196,15 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 
-unsigned long snmp_fold_field(void __percpu *mib[], int offt);
+unsigned long snmp_fold_field(void __percpu *mib, int offt);
 #if BITS_PER_LONG==32
-u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
+u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
 #else
-static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
+static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
 {
 	return snmp_fold_field(mib, offt);
 }
 #endif
-int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
-
-static inline void snmp_mib_free(void __percpu *ptr[SNMP_ARRAY_SZ])
-{
-	int i;
-
-	BUG_ON(ptr == NULL);
-	for (i = 0; i < SNMP_ARRAY_SZ; i++) {
-		free_percpu(ptr[i]);
-		ptr[i] = NULL;
-	}
-}
 
 void inet_get_local_port_range(struct net *net, int *low, int *high);
 
diff --git a/include/net/snmp.h b/include/net/snmp.h
index 71596261fa99..f1f27fdbb0d5 100644
--- a/include/net/snmp.h
+++ b/include/net/snmp.h
@@ -116,51 +116,49 @@ struct linux_xfrm_mib {
 	unsigned long	mibs[LINUX_MIB_XFRMMAX];
 };
 
-#define SNMP_ARRAY_SZ 1
-
 #define DEFINE_SNMP_STAT(type, name)	\
-	__typeof__(type) __percpu *name[SNMP_ARRAY_SZ]
+	__typeof__(type) __percpu *name
 #define DEFINE_SNMP_STAT_ATOMIC(type, name)	\
 	__typeof__(type) *name
 #define DECLARE_SNMP_STAT(type, name)	\
-	extern __typeof__(type) __percpu *name[SNMP_ARRAY_SZ]
+	extern __typeof__(type) __percpu *name
 
 #define SNMP_INC_STATS_BH(mib, field)	\
-			__this_cpu_inc(mib[0]->mibs[field])
+			__this_cpu_inc(mib->mibs[field])
 
 #define SNMP_INC_STATS_USER(mib, field)	\
-			this_cpu_inc(mib[0]->mibs[field])
+			this_cpu_inc(mib->mibs[field])
 
 #define SNMP_INC_STATS_ATOMIC_LONG(mib, field)	\
 			atomic_long_inc(&mib->mibs[field])
 
 #define SNMP_INC_STATS(mib, field)	\
-			this_cpu_inc(mib[0]->mibs[field])
+			this_cpu_inc(mib->mibs[field])
 
 #define SNMP_DEC_STATS(mib, field)	\
-			this_cpu_dec(mib[0]->mibs[field])
+			this_cpu_dec(mib->mibs[field])
 
 #define SNMP_ADD_STATS_BH(mib, field, addend)	\
-			__this_cpu_add(mib[0]->mibs[field], addend)
+			__this_cpu_add(mib->mibs[field], addend)
 
 #define SNMP_ADD_STATS_USER(mib, field, addend)	\
-			this_cpu_add(mib[0]->mibs[field], addend)
+			this_cpu_add(mib->mibs[field], addend)
 
 #define SNMP_ADD_STATS(mib, field, addend)	\
-			this_cpu_add(mib[0]->mibs[field], addend)
+			this_cpu_add(mib->mibs[field], addend)
 /*
- * Use "__typeof__(*mib[0]) *ptr" instead of "__typeof__(mib[0]) ptr"
+ * Use "__typeof__(*mib) *ptr" instead of "__typeof__(mib) ptr"
  * to make @ptr a non-percpu pointer.
  */
 #define SNMP_UPD_PO_STATS(mib, basefield, addend)	\
 	do { \
-		__typeof__(*mib[0]->mibs) *ptr = mib[0]->mibs;	\
+		__typeof__(*mib->mibs) *ptr = mib->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 { \
-		__typeof__(*mib[0]->mibs) *ptr = mib[0]->mibs;	\
+		__typeof__(*mib->mibs) *ptr = mib->mibs;	\
 		__this_cpu_inc(ptr[basefield##PKTS]);		\
 		__this_cpu_add(ptr[basefield##OCTETS], addend);	\
 	} while (0)
@@ -170,7 +168,7 @@ struct linux_xfrm_mib {
 
 #define SNMP_ADD_STATS64_BH(mib, field, addend) 			\
 	do {								\
-		__typeof__(*mib[0]) *ptr = __this_cpu_ptr((mib)[0]);	\
+		__typeof__(*mib) *ptr = __this_cpu_ptr(mib);		\
 		u64_stats_update_begin(&ptr->syncp);			\
 		ptr->mibs[field] += addend;				\
 		u64_stats_update_end(&ptr->syncp);			\
@@ -191,8 +189,8 @@ struct linux_xfrm_mib {
 #define SNMP_INC_STATS64(mib, field) SNMP_ADD_STATS64(mib, field, 1)
 #define SNMP_UPD_PO_STATS64_BH(mib, basefield, addend)			\
 	do {								\
-		__typeof__(*mib[0]) *ptr;				\
-		ptr = __this_cpu_ptr((mib)[0]);				\
+		__typeof__(*mib) *ptr;					\
+		ptr = __this_cpu_ptr(mib);				\
 		u64_stats_update_begin(&ptr->syncp);			\
 		ptr->mibs[basefield##PKTS]++;				\
 		ptr->mibs[basefield##OCTETS] += addend;			\