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>

2 files changed, 4 insertions, 3 deletions

diff --git a/net/sctp/proc.c b/net/sctp/proc.c
index a5ac6e0a8d9c..784bcc9a979d 100644
--- a/net/sctp/proc.c
+++ b/net/sctp/proc.c
@@ -83,7 +83,7 @@ static int sctp_snmp_seq_show(struct seq_file *seq, void *v)
 
         for (i = 0; sctp_snmp_list[i].name != NULL; i++)
                 seq_printf(seq, "%-32s\t%ld\n", sctp_snmp_list[i].name,
-                           snmp_fold_field((void **)sctp_statistics,
+                           snmp_fold_field((void __percpu **)sctp_statistics,
                                       sctp_snmp_list[i].entry));
 
         return 0;
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index a3c8988758b1..9687177b026b 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -996,12 +996,13 @@ int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
 
 static inline int init_sctp_mibs(void)
 {
-        return snmp_mib_init((void**)sctp_statistics, sizeof(struct sctp_mib));
+        return snmp_mib_init((void __percpu **)sctp_statistics,
+                             sizeof(struct sctp_mib));
 }
 
 static inline void cleanup_sctp_mibs(void)
 {
-        snmp_mib_free((void**)sctp_statistics);
+        snmp_mib_free((void __percpu **)sctp_statistics);
 }
 
 static void sctp_v4_pf_init(void)