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>

3 files changed, 39 insertions, 36 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index c79cbff..b0d4a4b 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -278,31 +278,31 @@ static void addrconf_mod_timer(struct inet6_ifaddr *ifp,
 
 static int snmp6_alloc_dev(struct inet6_dev *idev)
 {
-	if (snmp_mib_init((void **)idev->stats.ipv6,
+	if (snmp_mib_init((void __percpu **)idev->stats.ipv6,
 			  sizeof(struct ipstats_mib)) < 0)
 		goto err_ip;
-	if (snmp_mib_init((void **)idev->stats.icmpv6,
+	if (snmp_mib_init((void __percpu **)idev->stats.icmpv6,
 			  sizeof(struct icmpv6_mib)) < 0)
 		goto err_icmp;
-	if (snmp_mib_init((void **)idev->stats.icmpv6msg,
+	if (snmp_mib_init((void __percpu **)idev->stats.icmpv6msg,
 			  sizeof(struct icmpv6msg_mib)) < 0)
 		goto err_icmpmsg;
 
 	return 0;
 
 err_icmpmsg:
-	snmp_mib_free((void **)idev->stats.icmpv6);
+	snmp_mib_free((void __percpu **)idev->stats.icmpv6);
 err_icmp:
-	snmp_mib_free((void **)idev->stats.ipv6);
+	snmp_mib_free((void __percpu **)idev->stats.ipv6);
 err_ip:
 	return -ENOMEM;
 }
 
 static void snmp6_free_dev(struct inet6_dev *idev)
 {
-	snmp_mib_free((void **)idev->stats.icmpv6msg);
-	snmp_mib_free((void **)idev->stats.icmpv6);
-	snmp_mib_free((void **)idev->stats.ipv6);
+	snmp_mib_free((void __percpu **)idev->stats.icmpv6msg);
+	snmp_mib_free((void __percpu **)idev->stats.icmpv6);
+	snmp_mib_free((void __percpu **)idev->stats.ipv6);
 }
 
 /* Nobody refers to this device, we may destroy it. */
@@ -3766,8 +3766,8 @@ static inline size_t inet6_if_nlmsg_size(void)
 		 );
 }
 
-static inline void __snmp6_fill_stats(u64 *stats, void **mib, int items,
-				      int bytes)
+static inline void __snmp6_fill_stats(u64 *stats, void __percpu **mib,
+				      int items, int bytes)
 {
 	int i;
 	int pad = bytes - sizeof(u64) * items;
@@ -3786,10 +3786,10 @@ static void snmp6_fill_stats(u64 *stats, struct inet6_dev *idev, int attrtype,
 {
 	switch(attrtype) {
 	case IFLA_INET6_STATS:
-		__snmp6_fill_stats(stats, (void **)idev->stats.ipv6, IPSTATS_MIB_MAX, bytes);
+		__snmp6_fill_stats(stats, (void __percpu **)idev->stats.ipv6, IPSTATS_MIB_MAX, bytes);
 		break;
 	case IFLA_INET6_ICMP6STATS:
-		__snmp6_fill_stats(stats, (void **)idev->stats.icmpv6, ICMP6_MIB_MAX, bytes);
+		__snmp6_fill_stats(stats, (void __percpu **)idev->stats.icmpv6, ICMP6_MIB_MAX, bytes);
 		break;
 	}
 }
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index e29160f..37d14e7 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -971,41 +971,41 @@ static void ipv6_packet_cleanup(void)
 
 static int __net_init ipv6_init_mibs(struct net *net)
 {
-	if (snmp_mib_init((void **)net->mib.udp_stats_in6,
+	if (snmp_mib_init((void __percpu **)net->mib.udp_stats_in6,
 			  sizeof (struct udp_mib)) < 0)
 		return -ENOMEM;
-	if (snmp_mib_init((void **)net->mib.udplite_stats_in6,
+	if (snmp_mib_init((void __percpu **)net->mib.udplite_stats_in6,
 			  sizeof (struct udp_mib)) < 0)
 		goto err_udplite_mib;
-	if (snmp_mib_init((void **)net->mib.ipv6_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.ipv6_statistics,
 			  sizeof(struct ipstats_mib)) < 0)
 		goto err_ip_mib;
-	if (snmp_mib_init((void **)net->mib.icmpv6_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.icmpv6_statistics,
 			  sizeof(struct icmpv6_mib)) < 0)
 		goto err_icmp_mib;
-	if (snmp_mib_init((void **)net->mib.icmpv6msg_statistics,
+	if (snmp_mib_init((void __percpu **)net->mib.icmpv6msg_statistics,
 			  sizeof(struct icmpv6msg_mib)) < 0)
 		goto err_icmpmsg_mib;
 	return 0;
 
 err_icmpmsg_mib:
-	snmp_mib_free((void **)net->mib.icmpv6_statistics);
+	snmp_mib_free((void __percpu **)net->mib.icmpv6_statistics);
 err_icmp_mib:
-	snmp_mib_free((void **)net->mib.ipv6_statistics);
+	snmp_mib_free((void __percpu **)net->mib.ipv6_statistics);
 err_ip_mib:
-	snmp_mib_free((void **)net->mib.udplite_stats_in6);
+	snmp_mib_free((void __percpu **)net->mib.udplite_stats_in6);
 err_udplite_mib:
-	snmp_mib_free((void **)net->mib.udp_stats_in6);
+	snmp_mib_free((void __percpu **)net->mib.udp_stats_in6);
 	return -ENOMEM;
 }
 
 static void ipv6_cleanup_mibs(struct net *net)
 {
-	snmp_mib_free((void **)net->mib.udp_stats_in6);
-	snmp_mib_free((void **)net->mib.udplite_stats_in6);
-	snmp_mib_free((void **)net->mib.ipv6_statistics);
-	snmp_mib_free((void **)net->mib.icmpv6_statistics);
-	snmp_mib_free((void **)net->mib.icmpv6msg_statistics);
+	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);
+	snmp_mib_free((void __percpu **)net->mib.icmpv6msg_statistics);
 }
 
 static int __net_init inet6_net_init(struct net *net)
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index bfe2598..58344c0 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -136,7 +136,7 @@ static const struct snmp_mib snmp6_udplite6_list[] = {
 	SNMP_MIB_SENTINEL
 };
 
-static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, void **mib)
+static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, void __percpu **mib)
 {
 	char name[32];
 	int i;
@@ -170,7 +170,7 @@ static void snmp6_seq_show_icmpv6msg(struct seq_file *seq, void **mib)
 	return;
 }
 
-static void snmp6_seq_show_item(struct seq_file *seq, void **mib,
+static void snmp6_seq_show_item(struct seq_file *seq, void __percpu **mib,
 				const struct snmp_mib *itemlist)
 {
 	int i;
@@ -183,14 +183,15 @@ static int snmp6_seq_show(struct seq_file *seq, void *v)
 {
 	struct net *net = (struct net *)seq->private;
 
-	snmp6_seq_show_item(seq, (void **)net->mib.ipv6_statistics,
+	snmp6_seq_show_item(seq, (void __percpu **)net->mib.ipv6_statistics,
 			    snmp6_ipstats_list);
-	snmp6_seq_show_item(seq, (void **)net->mib.icmpv6_statistics,
+	snmp6_seq_show_item(seq, (void __percpu **)net->mib.icmpv6_statistics,
 			    snmp6_icmp6_list);
-	snmp6_seq_show_icmpv6msg(seq, (void **)net->mib.icmpv6msg_statistics);
-	snmp6_seq_show_item(seq, (void **)net->mib.udp_stats_in6,
+	snmp6_seq_show_icmpv6msg(seq,
+			    (void __percpu **)net->mib.icmpv6msg_statistics);
+	snmp6_seq_show_item(seq, (void __percpu **)net->mib.udp_stats_in6,
 			    snmp6_udp6_list);
-	snmp6_seq_show_item(seq, (void **)net->mib.udplite_stats_in6,
+	snmp6_seq_show_item(seq, (void __percpu **)net->mib.udplite_stats_in6,
 			    snmp6_udplite6_list);
 	return 0;
 }
@@ -213,9 +214,11 @@ 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_item(seq, (void **)idev->stats.ipv6, snmp6_ipstats_list);
-	snmp6_seq_show_item(seq, (void **)idev->stats.icmpv6, snmp6_icmp6_list);
-	snmp6_seq_show_icmpv6msg(seq, (void **)idev->stats.icmpv6msg);
+	snmp6_seq_show_item(seq, (void __percpu **)idev->stats.ipv6,
+			    snmp6_ipstats_list);
+	snmp6_seq_show_item(seq, (void __percpu **)idev->stats.icmpv6,
+			    snmp6_icmp6_list);
+	snmp6_seq_show_icmpv6msg(seq, (void __percpu **)idev->stats.icmpv6msg);
 	return 0;
 }