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 42cd183..0fc5ff6 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 eb870fc..cfceb66 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 c083a4e..003f2c4 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;
 }