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, 13 insertions, 12 deletions

diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
index 42cd18391f46..0fc5ff66d1fa 100644
--- a/net/xfrm/xfrm_ipcomp.c
+++ b/net/xfrm/xfrm_ipcomp.c
@@ -30,12 +30,12 @@
 
 struct ipcomp_tfms {
         struct list_head list;
-        struct crypto_comp **tfms;
+        struct crypto_comp * __percpu *tfms;
         int users;
 };
 
 static DEFINE_MUTEX(ipcomp_resource_mutex);
-static void **ipcomp_scratches;
+static void * __percpu *ipcomp_scratches;
 static int ipcomp_scratch_users;
 static LIST_HEAD(ipcomp_tfms_list);
 
@@ -200,7 +200,7 @@ EXPORT_SYMBOL_GPL(ipcomp_output);
 static void ipcomp_free_scratches(void)
 {
         int i;
-        void **scratches;
+        void * __percpu *scratches;
 
         if (--ipcomp_scratch_users)
                 return;
@@ -215,10 +215,10 @@ static void ipcomp_free_scratches(void)
         free_percpu(scratches);
 }
 
-static void **ipcomp_alloc_scratches(void)
+static void * __percpu *ipcomp_alloc_scratches(void)
 {
         int i;
-        void **scratches;
+        void * __percpu *scratches;
 
         if (ipcomp_scratch_users++)
                 return ipcomp_scratches;
@@ -239,7 +239,7 @@ static void **ipcomp_alloc_scratches(void)
         return scratches;
 }
 
-static void ipcomp_free_tfms(struct crypto_comp **tfms)
+static void ipcomp_free_tfms(struct crypto_comp * __percpu *tfms)
 {
         struct ipcomp_tfms *pos;
         int cpu;
@@ -267,10 +267,10 @@ static void ipcomp_free_tfms(struct crypto_comp **tfms)
         free_percpu(tfms);
 }
 
-static struct crypto_comp **ipcomp_alloc_tfms(const char *alg_name)
+static struct crypto_comp * __percpu *ipcomp_alloc_tfms(const char *alg_name)
 {
         struct ipcomp_tfms *pos;
-        struct crypto_comp **tfms;
+        struct crypto_comp * __percpu *tfms;
         int cpu;
 
         /* This can be any valid CPU ID so we don't need locking. */
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index eb870fcc29cc..cfceb6616ec1 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2428,19 +2428,19 @@ static int __net_init xfrm_statistics_init(struct net *net)
 {
         int rv;
 
-        if (snmp_mib_init((void **)net->mib.xfrm_statistics,
+        if (snmp_mib_init((void __percpu **)net->mib.xfrm_statistics,
                           sizeof(struct linux_xfrm_mib)) < 0)
                 return -ENOMEM;
         rv = xfrm_proc_init(net);
         if (rv < 0)
-                snmp_mib_free((void **)net->mib.xfrm_statistics);
+                snmp_mib_free((void __percpu **)net->mib.xfrm_statistics);
         return rv;
 }
 
 static void xfrm_statistics_fini(struct net *net)
 {
         xfrm_proc_fini(net);
-        snmp_mib_free((void **)net->mib.xfrm_statistics);
+        snmp_mib_free((void __percpu **)net->mib.xfrm_statistics);
 }
 #else
 static int __net_init xfrm_statistics_init(struct net *net)
diff --git a/net/xfrm/xfrm_proc.c b/net/xfrm/xfrm_proc.c
index c083a4e4e796..003f2c437ac3 100644
--- a/net/xfrm/xfrm_proc.c
+++ b/net/xfrm/xfrm_proc.c
@@ -50,7 +50,8 @@ static int xfrm_statistics_seq_show(struct seq_file *seq, void *v)
         int i;
         for (i=0; xfrm_mib_list[i].name; i++)
                 seq_printf(seq, "%-24s\t%lu\n", xfrm_mib_list[i].name,
-                           snmp_fold_field((void **)net->mib.xfrm_statistics,
+                           snmp_fold_field((void __percpu **)
+                                           net->mib.xfrm_statistics,
                                            xfrm_mib_list[i].entry));
         return 0;
 }