percpu: add __percpu sparse annotations to net

Add __percpu sparse annotations to net.

These annotations are to make sparse consider percpu variables to be
in a different address space and warn if accessed without going
through percpu accessors.  This patch doesn't affect normal builds.

The macro and type tricks around snmp stats make things a bit
interesting.  DEFINE/DECLARE_SNMP_STAT() macros mark the target field
as __percpu and SNMP_UPD_PO_STATS() macro is updated accordingly.  All
snmp_mib_*() users which used to cast the argument to (void **) are
updated to cast it to (void __percpu **).

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Vlad Yasevich <vladislav.yasevich@hp.com>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -174,9 +174,9 @@ extern struct ipv4_config ipv4_config;
 #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)
 
-extern unsigned long snmp_fold_field(void *mib[], int offt);
-extern int snmp_mib_init(void *ptr[2], size_t mibsize);
-extern void snmp_mib_free(void *ptr[2]);
+extern unsigned long snmp_fold_field(void __percpu *mib[], int offt);
+extern int snmp_mib_init(void __percpu *ptr[2], size_t mibsize);
+extern void snmp_mib_free(void __percpu *ptr[2]);
 
 extern struct local_ports {
 	seqlock_t	lock;

include/net/ipcomp.h

@@ -9,7 +9,7 @@ struct crypto_comp;
 
 struct ipcomp_data {
 	u16 threshold;
-	struct crypto_comp **tfms;
+	struct crypto_comp * __percpu *tfms;
 };
 
 struct ip_comp_hdr;

include/net/neighbour.h

@@ -164,7 +164,7 @@ struct neigh_table {
 	rwlock_t		lock;
 	unsigned long		last_rand;
 	struct kmem_cache		*kmem_cachep;
-	struct neigh_statistics	*stats;
+	struct neigh_statistics	__percpu *stats;
 	struct neighbour	**hash_buckets;
 	unsigned int		hash_mask;
 	__u32			hash_rnd;

include/net/netns/conntrack.h

@@ -17,7 +17,7 @@ struct netns_ct {
 	struct hlist_head	*expect_hash;
 	struct hlist_nulls_head	unconfirmed;
 	struct hlist_nulls_head	dying;
-	struct ip_conntrack_stat *stat;
+	struct ip_conntrack_stat __percpu *stat;
 	int			sysctl_events;
 	unsigned int		sysctl_events_retry_timeout;
 	int			sysctl_acct;

include/net/netns/core.h

@@ -10,7 +10,7 @@ struct netns_core {
 
 	int	sysctl_somaxconn;
 
-	struct prot_inuse	*inuse;
+	struct prot_inuse __percpu *inuse;
 };
 
 #endif

include/net/route.h

@@ -101,7 +101,7 @@ struct rt_cache_stat {
         unsigned int out_hlist_search;
 };
 
-extern struct ip_rt_acct *ip_rt_acct;
+extern struct ip_rt_acct __percpu *ip_rt_acct;
 
 struct in_device;
 extern int		ip_rt_init(void);

include/net/snmp.h

@@ -129,9 +129,9 @@ struct linux_xfrm_mib {
  * nonlocked_atomic_inc() primitives -AK
  */ 
 #define DEFINE_SNMP_STAT(type, name)	\
-	__typeof__(type) *name[2]
+	__typeof__(type) __percpu *name[2]
 #define DECLARE_SNMP_STAT(type, name)	\
-	extern __typeof__(type) *name[2]
+	extern __typeof__(type) __percpu *name[2]
 
 #define SNMP_STAT_BHPTR(name)	(name[0])
 #define SNMP_STAT_USRPTR(name)	(name[1])
@@ -148,9 +148,13 @@ struct linux_xfrm_mib {
 			__this_cpu_add(mib[0]->mibs[field], addend)
 #define SNMP_ADD_STATS_USER(mib, field, addend)	\
 			this_cpu_add(mib[1]->mibs[field], addend)
+/*
+ * Use "__typeof__(*mib[0]) *ptr" instead of "__typeof__(mib[0]) ptr"
+ * to make @ptr a non-percpu pointer.
+ */
 #define SNMP_UPD_PO_STATS(mib, basefield, addend)	\
 	do { \
-		__typeof__(mib[0]) ptr; \
+		__typeof__(*mib[0]) *ptr; \
 		preempt_disable(); \
 		ptr = this_cpu_ptr((mib)[!in_softirq()]); \
 		ptr->mibs[basefield##PKTS]++; \
@@ -159,7 +163,7 @@ struct linux_xfrm_mib {
 	} while (0)
 #define SNMP_UPD_PO_STATS_BH(mib, basefield, addend)	\
 	do { \
-		__typeof__(mib[0]) ptr = \
+		__typeof__(*mib[0]) *ptr = \
 			__this_cpu_ptr((mib)[!in_softirq()]); \
 		ptr->mibs[basefield##PKTS]++; \
 		ptr->mibs[basefield##OCTETS] += addend;\

include/net/tcp.h

@@ -1189,7 +1189,7 @@ extern int			tcp_v4_md5_do_del(struct sock *sk,
 #define tcp_twsk_md5_key(twsk)	NULL
 #endif
 
-extern struct tcp_md5sig_pool	**tcp_alloc_md5sig_pool(struct sock *);
+extern struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *);
 extern void			tcp_free_md5sig_pool(void);
 
 extern struct tcp_md5sig_pool	*__tcp_get_md5sig_pool(int cpu);

net/8021q/vlan.h

@@ -61,7 +61,7 @@ struct vlan_dev_info {
 	struct proc_dir_entry			*dent;
 	unsigned long				cnt_inc_headroom_on_tx;
 	unsigned long				cnt_encap_on_xmit;
-	struct vlan_rx_stats			*vlan_rx_stats;
+	struct vlan_rx_stats __percpu		*vlan_rx_stats;
 };
 
 static inline struct vlan_dev_info *vlan_dev_info(const struct net_device *dev)

net/dccp/proto.c

@@ -1005,12 +1005,13 @@ EXPORT_SYMBOL_GPL(dccp_shutdown);
 
 static inline int dccp_mib_init(void)
 {
-	return snmp_mib_init((void**)dccp_statistics, sizeof(struct dccp_mib));
+	return snmp_mib_init((void __percpu **)dccp_statistics,
+			     sizeof(struct dccp_mib));
 }
 
 static inline void dccp_mib_exit(void)
 {
-	snmp_mib_free((void**)dccp_statistics);
+	snmp_mib_free((void __percpu **)dccp_statistics);
 }
 
 static int thash_entries;

net/ipv4/af_inet.c

@@ -1385,7 +1385,7 @@ int inet_ctl_sock_create(struct sock **sk, unsigned short family,
 }
 EXPORT_SYMBOL_GPL(inet_ctl_sock_create);
 
-unsigned long snmp_fold_field(void *mib[], int offt)
+unsigned long snmp_fold_field(void __percpu *mib[], int offt)
 {
 	unsigned long res = 0;
 	int i;
@@ -1398,7 +1398,7 @@ unsigned long snmp_fold_field(void *mib[], int offt)
 }
 EXPORT_SYMBOL_GPL(snmp_fold_field);
 
-int snmp_mib_init(void *ptr[2], size_t mibsize)
+int snmp_mib_init(void __percpu *ptr[2], size_t mibsize)
 {
 	BUG_ON(ptr == NULL);
 	ptr[0] = __alloc_percpu(mibsize, __alignof__(unsigned long long));
@@ -1416,7 +1416,7 @@ int snmp_mib_init(void *ptr[2], size_t mibsize)
 }
 EXPORT_SYMBOL_GPL(snmp_mib_init);
 
-void snmp_mib_free(void *ptr[2])
+void snmp_mib_free(void __percpu *ptr[2])
 {
 	BUG_ON(ptr == NULL);
 	free_percpu(ptr[0]);
@@ -1460,56 +1460,56 @@ static const struct net_protocol icmp_protocol = {
 
 static __net_init int ipv4_mib_init_net(struct net *net)
 {
-	if (snmp_mib_init((void **)net->mib.tcp_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.tcp_statistics,
 			  sizeof(struct tcp_mib)) < 0)
 		goto err_tcp_mib;
-	if (snmp_mib_init((void **)net->mib.ip_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.ip_statistics,
 			  sizeof(struct ipstats_mib)) < 0)
 		goto err_ip_mib;
-	if (snmp_mib_init((void **)net->mib.net_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.net_statistics,
 			  sizeof(struct linux_mib)) < 0)
 		goto err_net_mib;
-	if (snmp_mib_init((void **)net->mib.udp_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.udp_statistics,
 			  sizeof(struct udp_mib)) < 0)
 		goto err_udp_mib;
-	if (snmp_mib_init((void **)net->mib.udplite_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.udplite_statistics,
 			  sizeof(struct udp_mib)) < 0)
 		goto err_udplite_mib;
-	if (snmp_mib_init((void **)net->mib.icmp_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.icmp_statistics,
 			  sizeof(struct icmp_mib)) < 0)
 		goto err_icmp_mib;
-	if (snmp_mib_init((void **)net->mib.icmpmsg_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.icmpmsg_statistics,
 			  sizeof(struct icmpmsg_mib)) < 0)
 		goto err_icmpmsg_mib;
 
 	tcp_mib_init(net);
 	return 0;
 
 err_icmpmsg_mib:
-	snmp_mib_free((void **)net->mib.icmp_statistics);
+	snmp_mib_free((void __percpu **)net->mib.icmp_statistics);
 err_icmp_mib:
-	snmp_mib_free((void **)net->mib.udplite_statistics);
+	snmp_mib_free((void __percpu **)net->mib.udplite_statistics);
 err_udplite_mib:
-	snmp_mib_free((void **)net->mib.udp_statistics);
+	snmp_mib_free((void __percpu **)net->mib.udp_statistics);
 err_udp_mib:
-	snmp_mib_free((void **)net->mib.net_statistics);
+	snmp_mib_free((void __percpu **)net->mib.net_statistics);
 err_net_mib:
-	snmp_mib_free((void **)net->mib.ip_statistics);
+	snmp_mib_free((void __percpu **)net->mib.ip_statistics);
 err_ip_mib:
-	snmp_mib_free((void **)net->mib.tcp_statistics);
+	snmp_mib_free((void __percpu **)net->mib.tcp_statistics);
 err_tcp_mib:
 	return -ENOMEM;
 }
 
 static __net_exit void ipv4_mib_exit_net(struct net *net)
 {
-	snmp_mib_free((void **)net->mib.icmpmsg_statistics);
-	snmp_mib_free((void **)net->mib.icmp_statistics);
-	snmp_mib_free((void **)net->mib.udplite_statistics);
-	snmp_mib_free((void **)net->mib.udp_statistics);
-	snmp_mib_free((void **)net->mib.net_statistics);
-	snmp_mib_free((void **)net->mib.ip_statistics);
-	snmp_mib_free((void **)net->mib.tcp_statistics);
+	snmp_mib_free((void __percpu **)net->mib.icmpmsg_statistics);
+	snmp_mib_free((void __percpu **)net->mib.icmp_statistics);
+	snmp_mib_free((void __percpu **)net->mib.udplite_statistics);
+	snmp_mib_free((void __percpu **)net->mib.udp_statistics);
+	snmp_mib_free((void __percpu **)net->mib.net_statistics);
+	snmp_mib_free((void __percpu **)net->mib.ip_statistics);
+	snmp_mib_free((void __percpu **)net->mib.tcp_statistics);
 }
 
 static __net_initdata struct pernet_operations ipv4_mib_ops = {

net/ipv4/proc.c

@@ -280,7 +280,7 @@ static void icmpmsg_put(struct seq_file *seq)
 
 	count = 0;
 	for (i = 0; i < ICMPMSG_MIB_MAX; i++) {
-		val = snmp_fold_field((void **) net->mib.icmpmsg_statistics, i);
+		val = snmp_fold_field((void __percpu **) net->mib.icmpmsg_statistics, i);
 		if (val) {
 			type[count] = i;
 			vals[count++] = val;
@@ -307,18 +307,18 @@ static void icmp_put(struct seq_file *seq)
 	for (i=0; icmpmibmap[i].name != NULL; i++)
 		seq_printf(seq, " Out%s", icmpmibmap[i].name);
 	seq_printf(seq, "\nIcmp: %lu %lu",
-		snmp_fold_field((void **) net->mib.icmp_statistics, ICMP_MIB_INMSGS),
-		snmp_fold_field((void **) net->mib.icmp_statistics, ICMP_MIB_INERRORS));
+		snmp_fold_field((void __percpu **) net->mib.icmp_statistics, ICMP_MIB_INMSGS),
+		snmp_fold_field((void __percpu **) net->mib.icmp_statistics, ICMP_MIB_INERRORS));
 	for (i=0; icmpmibmap[i].name != NULL; i++)
 		seq_printf(seq, " %lu",
-			snmp_fold_field((void **) net->mib.icmpmsg_statistics,
+			snmp_fold_field((void __percpu **) net->mib.icmpmsg_statistics,
 				icmpmibmap[i].index));
 	seq_printf(seq, " %lu %lu",
-		snmp_fold_field((void **) net->mib.icmp_statistics, ICMP_MIB_OUTMSGS),
-		snmp_fold_field((void **) net->mib.icmp_statistics, ICMP_MIB_OUTERRORS));
+		snmp_fold_field((void __percpu **) net->mib.icmp_statistics, ICMP_MIB_OUTMSGS),
+		snmp_fold_field((void __percpu **) net->mib.icmp_statistics, ICMP_MIB_OUTERRORS));
 	for (i=0; icmpmibmap[i].name != NULL; i++)
 		seq_printf(seq, " %lu",
-			snmp_fold_field((void **) net->mib.icmpmsg_statistics,
+			snmp_fold_field((void __percpu **) net->mib.icmpmsg_statistics,
 				icmpmibmap[i].index | 0x100));
 }
 
@@ -341,7 +341,7 @@ static int snmp_seq_show(struct seq_file *seq, void *v)
 
 	for (i = 0; snmp4_ipstats_list[i].name != NULL; i++)
 		seq_printf(seq, " %lu",
-			   snmp_fold_field((void **)net->mib.ip_statistics,
+			   snmp_fold_field((void __percpu **)net->mib.ip_statistics,
 					   snmp4_ipstats_list[i].entry));
 
 	icmp_put(seq);	/* RFC 2011 compatibility */
@@ -356,11 +356,11 @@ static int snmp_seq_show(struct seq_file *seq, void *v)
 		/* MaxConn field is signed, RFC 2012 */
 		if (snmp4_tcp_list[i].entry == TCP_MIB_MAXCONN)
 			seq_printf(seq, " %ld",
-				   snmp_fold_field((void **)net->mib.tcp_statistics,
+				   snmp_fold_field((void __percpu **)net->mib.tcp_statistics,
 						   snmp4_tcp_list[i].entry));
 		else
 			seq_printf(seq, " %lu",
-				   snmp_fold_field((void **)net->mib.tcp_statistics,
+				   snmp_fold_field((void __percpu **)net->mib.tcp_statistics,
 						   snmp4_tcp_list[i].entry));
 	}
 
@@ -371,7 +371,7 @@ static int snmp_seq_show(struct seq_file *seq, void *v)
 	seq_puts(seq, "\nUdp:");
 	for (i = 0; snmp4_udp_list[i].name != NULL; i++)
 		seq_printf(seq, " %lu",
-			   snmp_fold_field((void **)net->mib.udp_statistics,
+			   snmp_fold_field((void __percpu **)net->mib.udp_statistics,
 					   snmp4_udp_list[i].entry));
 
 	/* the UDP and UDP-Lite MIBs are the same */
@@ -382,7 +382,7 @@ static int snmp_seq_show(struct seq_file *seq, void *v)
 	seq_puts(seq, "\nUdpLite:");
 	for (i = 0; snmp4_udp_list[i].name != NULL; i++)
 		seq_printf(seq, " %lu",
-			   snmp_fold_field((void **)net->mib.udplite_statistics,
+			   snmp_fold_field((void __percpu **)net->mib.udplite_statistics,
 					   snmp4_udp_list[i].entry));
 
 	seq_putc(seq, '\n');
@@ -419,7 +419,7 @@ static int netstat_seq_show(struct seq_file *seq, void *v)
 	seq_puts(seq, "\nTcpExt:");
 	for (i = 0; snmp4_net_list[i].name != NULL; i++)
 		seq_printf(seq, " %lu",
-			   snmp_fold_field((void **)net->mib.net_statistics,
+			   snmp_fold_field((void __percpu **)net->mib.net_statistics,
 					   snmp4_net_list[i].entry));
 
 	seq_puts(seq, "\nIpExt:");
@@ -429,7 +429,7 @@ static int netstat_seq_show(struct seq_file *seq, void *v)
 	seq_puts(seq, "\nIpExt:");
 	for (i = 0; snmp4_ipextstats_list[i].name != NULL; i++)
 		seq_printf(seq, " %lu",
-			   snmp_fold_field((void **)net->mib.ip_statistics,
+			   snmp_fold_field((void __percpu **)net->mib.ip_statistics,
 					   snmp4_ipextstats_list[i].entry));
 
 	seq_putc(seq, '\n');

net/ipv4/route.c

@@ -3334,7 +3334,7 @@ static __net_initdata struct pernet_operations rt_secret_timer_ops = {
 
 
 #ifdef CONFIG_NET_CLS_ROUTE
-struct ip_rt_acct *ip_rt_acct __read_mostly;
+struct ip_rt_acct __percpu *ip_rt_acct __read_mostly;
 #endif /* CONFIG_NET_CLS_ROUTE */
 
 static __initdata unsigned long rhash_entries;