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>

4 files changed, 27 insertions, 40 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1ac13c0300b7..5667b3003af9 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -275,19 +275,14 @@ static int snmp6_alloc_dev(struct inet6_dev *idev)
 {
 	int i;
 
-	if (snmp_mib_init((void __percpu **)idev->stats.ipv6,
-			  sizeof(struct ipstats_mib),
-			  __alignof__(struct ipstats_mib)) < 0)
+	idev->stats.ipv6 = alloc_percpu(struct ipstats_mib);
+	if (!idev->stats.ipv6)
 		goto err_ip;
 
 	for_each_possible_cpu(i) {
 		struct ipstats_mib *addrconf_stats;
-		addrconf_stats = per_cpu_ptr(idev->stats.ipv6[0], i);
+		addrconf_stats = per_cpu_ptr(idev->stats.ipv6, i);
 		u64_stats_init(&addrconf_stats->syncp);
-#if SNMP_ARRAY_SZ == 2
-		addrconf_stats = per_cpu_ptr(idev->stats.ipv6[1], i);
-		u64_stats_init(&addrconf_stats->syncp);
-#endif
 	}
 
 
@@ -305,7 +300,7 @@ static int snmp6_alloc_dev(struct inet6_dev *idev)
 err_icmpmsg:
 	kfree(idev->stats.icmpv6dev);
 err_icmp:
-	snmp_mib_free((void __percpu **)idev->stats.ipv6);
+	free_percpu(idev->stats.ipv6);
 err_ip:
 	return -ENOMEM;
 }
@@ -4363,7 +4358,7 @@ static inline void __snmp6_fill_statsdev(u64 *stats, atomic_long_t *mib,
 	memset(&stats[items], 0, pad);
 }
 
-static inline void __snmp6_fill_stats64(u64 *stats, void __percpu **mib,
+static inline void __snmp6_fill_stats64(u64 *stats, void __percpu *mib,
 				      int items, int bytes, size_t syncpoff)
 {
 	int i;
@@ -4383,7 +4378,7 @@ static void snmp6_fill_stats(u64 *stats, struct inet6_dev *idev, int attrtype,
 {
 	switch (attrtype) {
 	case IFLA_INET6_STATS:
-		__snmp6_fill_stats64(stats, (void __percpu **)idev->stats.ipv6,
+		__snmp6_fill_stats64(stats, idev->stats.ipv6,
 				     IPSTATS_MIB_MAX, bytes, offsetof(struct ipstats_mib, syncp));
 		break;
 	case IFLA_INET6_ICMP6STATS:
diff --git a/net/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c
index 4c11cbcf8308..e6960457f625 100644
--- a/net/ipv6/addrconf_core.c
+++ b/net/ipv6/addrconf_core.c
@@ -123,7 +123,7 @@ static void snmp6_free_dev(struct inet6_dev *idev)
 {
 	kfree(idev->stats.icmpv6msgdev);
 	kfree(idev->stats.icmpv6dev);
-	snmp_mib_free((void __percpu **)idev->stats.ipv6);
+	free_percpu(idev->stats.ipv6);
 }
 
 /* Nobody refers to this device, we may destroy it. */
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index d935889f1008..dc47cc757b80 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -715,33 +715,25 @@ static int __net_init ipv6_init_mibs(struct net *net)
 {
 	int i;
 
-	if (snmp_mib_init((void __percpu **)net->mib.udp_stats_in6,
-			  sizeof(struct udp_mib),
-			  __alignof__(struct udp_mib)) < 0)
+	net->mib.udp_stats_in6 = alloc_percpu(struct udp_mib);
+	if (!net->mib.udp_stats_in6)
 		return -ENOMEM;
-	if (snmp_mib_init((void __percpu **)net->mib.udplite_stats_in6,
-			  sizeof(struct udp_mib),
-			  __alignof__(struct udp_mib)) < 0)
+	net->mib.udplite_stats_in6 = alloc_percpu(struct udp_mib);
+	if (!net->mib.udplite_stats_in6)
 		goto err_udplite_mib;
-	if (snmp_mib_init((void __percpu **)net->mib.ipv6_statistics,
-			  sizeof(struct ipstats_mib),
-			  __alignof__(struct ipstats_mib)) < 0)
+	net->mib.ipv6_statistics = alloc_percpu(struct ipstats_mib);
+	if (!net->mib.ipv6_statistics)
 		goto err_ip_mib;
 
 	for_each_possible_cpu(i) {
 		struct ipstats_mib *af_inet6_stats;
-		af_inet6_stats = per_cpu_ptr(net->mib.ipv6_statistics[0], i);
+		af_inet6_stats = per_cpu_ptr(net->mib.ipv6_statistics, i);
 		u64_stats_init(&af_inet6_stats->syncp);
-#if SNMP_ARRAY_SZ == 2
-		af_inet6_stats = per_cpu_ptr(net->mib.ipv6_statistics[1], i);
-		u64_stats_init(&af_inet6_stats->syncp);
-#endif
 	}
 
 
-	if (snmp_mib_init((void __percpu **)net->mib.icmpv6_statistics,
-			  sizeof(struct icmpv6_mib),
-			  __alignof__(struct icmpv6_mib)) < 0)
+	net->mib.icmpv6_statistics = alloc_percpu(struct icmpv6_mib);
+	if (!net->mib.icmpv6_statistics)
 		goto err_icmp_mib;
 	net->mib.icmpv6msg_statistics = kzalloc(sizeof(struct icmpv6msg_mib),
 						GFP_KERNEL);
@@ -750,22 +742,22 @@ static int __net_init ipv6_init_mibs(struct net *net)
 	return 0;
 
 err_icmpmsg_mib:
-	snmp_mib_free((void __percpu **)net->mib.icmpv6_statistics);
+	free_percpu(net->mib.icmpv6_statistics);
 err_icmp_mib:
-	snmp_mib_free((void __percpu **)net->mib.ipv6_statistics);
+	free_percpu(net->mib.ipv6_statistics);
 err_ip_mib:
-	snmp_mib_free((void __percpu **)net->mib.udplite_stats_in6);
+	free_percpu(net->mib.udplite_stats_in6);
 err_udplite_mib:
-	snmp_mib_free((void __percpu **)net->mib.udp_stats_in6);
+	free_percpu(net->mib.udp_stats_in6);
 	return -ENOMEM;
 }
 
 static void ipv6_cleanup_mibs(struct net *net)
 {
-	snmp_mib_free((void __percpu **)net->mib.udp_stats_in6);
-	snmp_mib_free((void __percpu **)net->mib.udplite_stats_in6);
-	snmp_mib_free((void __percpu **)net->mib.ipv6_statistics);
-	snmp_mib_free((void __percpu **)net->mib.icmpv6_statistics);
+	free_percpu(net->mib.udp_stats_in6);
+	free_percpu(net->mib.udplite_stats_in6);
+	free_percpu(net->mib.ipv6_statistics);
+	free_percpu(net->mib.icmpv6_statistics);
 	kfree(net->mib.icmpv6msg_statistics);
 }
 
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index 091d066a57b3..69cb47625df7 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -201,7 +201,7 @@ static void snmp6_seq_show_item(struct seq_file *seq, void __percpu **pcpumib,
 	}
 }
 
-static void snmp6_seq_show_item64(struct seq_file *seq, void __percpu **mib,
+static void snmp6_seq_show_item64(struct seq_file *seq, void __percpu *mib,
 				  const struct snmp_mib *itemlist, size_t syncpoff)
 {
 	int i;
@@ -215,7 +215,7 @@ static int snmp6_seq_show(struct seq_file *seq, void *v)
 {
 	struct net *net = (struct net *)seq->private;
 
-	snmp6_seq_show_item64(seq, (void __percpu **)net->mib.ipv6_statistics,
+	snmp6_seq_show_item64(seq, net->mib.ipv6_statistics,
 			    snmp6_ipstats_list, offsetof(struct ipstats_mib, syncp));
 	snmp6_seq_show_item(seq, (void __percpu **)net->mib.icmpv6_statistics,
 			    NULL, snmp6_icmp6_list);
@@ -245,7 +245,7 @@ static int snmp6_dev_seq_show(struct seq_file *seq, void *v)
 	struct inet6_dev *idev = (struct inet6_dev *)seq->private;
 
 	seq_printf(seq, "%-32s\t%u\n", "ifIndex", idev->dev->ifindex);
-	snmp6_seq_show_item64(seq, (void __percpu **)idev->stats.ipv6,
+	snmp6_seq_show_item64(seq, idev->stats.ipv6,
 			    snmp6_ipstats_list, offsetof(struct ipstats_mib, syncp));
 	snmp6_seq_show_item(seq, NULL, idev->stats.icmpv6dev->mibs,
 			    snmp6_icmp6_list);