[RFC v2][PATCH 03/11] net: switch sock_diag handlers to rare_write()

From: Kees Cook
Date: Wed Mar 29 2017 - 14:17:24 EST


This is a simple example a register/unregister case for __wr_rare markings,
which only needs a simple rare_write() call to make updates.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
net/core/sock_diag.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 6b10573cc9fa..67253026106f 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -14,7 +14,7 @@
#include <linux/inet_diag.h>
#include <linux/sock_diag.h>

-static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
+static const struct sock_diag_handler *sock_diag_handlers[AF_MAX] __wr_rare;
static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
static DEFINE_MUTEX(sock_diag_table_mutex);
static struct workqueue_struct *broadcast_wq;
@@ -194,7 +194,7 @@ int sock_diag_register(const struct sock_diag_handler *hndl)
if (sock_diag_handlers[hndl->family])
err = -EBUSY;
else
- sock_diag_handlers[hndl->family] = hndl;
+ rare_write(sock_diag_handlers[hndl->family], hndl);
mutex_unlock(&sock_diag_table_mutex);

return err;
@@ -210,7 +210,7 @@ void sock_diag_unregister(const struct sock_diag_handler *hnld)

mutex_lock(&sock_diag_table_mutex);
BUG_ON(sock_diag_handlers[family] != hnld);
- sock_diag_handlers[family] = NULL;
+ rare_write(sock_diag_handlers[family], NULL);
mutex_unlock(&sock_diag_table_mutex);
}
EXPORT_SYMBOL_GPL(sock_diag_unregister);
--
2.7.4