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>

8 files changed, 17 insertions, 13 deletions

diff --git a/include/net/ip.h b/include/net/ip.h
index 7bc47873e3fc..503994a38ed1 100644
--- a/include/net/ip.h
+++ b/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;
diff --git a/include/net/ipcomp.h b/include/net/ipcomp.h
index 2a1092abaa07..cc4f30cd7315 100644
--- a/include/net/ipcomp.h
+++ b/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;
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 7834f470d14a..da1d58be31b7 100644
--- a/include/net/neighbour.h
+++ b/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;
diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h
index 63d449807d9b..d4958d4c6574 100644
--- a/include/net/netns/conntrack.h
+++ b/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;
diff --git a/include/net/netns/core.h b/include/net/netns/core.h
index 24d4be76bbd1..78eb1ff75475 100644
--- a/include/net/netns/core.h
+++ b/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
diff --git a/include/net/route.h b/include/net/route.h
index bce6dd68d27b..2c9fba7f7731 100644
--- a/include/net/route.h
+++ b/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);
diff --git a/include/net/snmp.h b/include/net/snmp.h
index da02ee027d69..692ee0061dc4 100644
--- a/include/net/snmp.h
+++ b/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;\
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 87d164b9bd8f..75a00c80bdda 100644
--- a/include/net/tcp.h
+++ b/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);