filter: constify sk_run_filter()

sk_run_filter() doesnt write on skb, change its prototype to reflect
this.

Fix two af_packet comments.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 21 insertions, 19 deletions

diff --git a/net/core/filter.c b/net/core/filter.c
index ac4920a87be5..25500f16a18a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -88,7 +88,7 @@ enum {
 };
 
 /* No hurry in this branch */
-static void *__load_pointer(struct sk_buff *skb, int k)
+static void *__load_pointer(const struct sk_buff *skb, int k)
 {
         u8 *ptr = NULL;
 
@@ -102,7 +102,7 @@ static void *__load_pointer(struct sk_buff *skb, int k)
         return NULL;
 }
 
-static inline void *load_pointer(struct sk_buff *skb, int k,
+static inline void *load_pointer(const struct sk_buff *skb, int k,
                                  unsigned int size, void *buffer)
 {
         if (k >= 0)
@@ -160,7 +160,8 @@ EXPORT_SYMBOL(sk_filter);
  * and last instruction guaranteed to be a RET, we dont need to check
  * flen. (We used to pass to this function the length of filter)
  */
-unsigned int sk_run_filter(struct sk_buff *skb, const struct sock_filter *fentry)
+unsigned int sk_run_filter(const struct sk_buff *skb,
+                           const struct sock_filter *fentry)
 {
         void *ptr;
         u32 A = 0;                      /* Accumulator */
diff --git a/net/core/timestamping.c b/net/core/timestamping.c
index dac7ed687f60..b124d28ff1c8 100644
--- a/net/core/timestamping.c
+++ b/net/core/timestamping.c
@@ -26,7 +26,7 @@ static struct sock_filter ptp_filter[] = {
         PTP_FILTER
 };
 
-static unsigned int classify(struct sk_buff *skb)
+static unsigned int classify(const struct sk_buff *skb)
 {
         if (likely(skb->dev &&
                    skb->dev->phydev &&
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index a11c731d2ee4..17eafe5b48c6 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -517,7 +517,8 @@ out_free:
         return err;
 }
 
-static inline unsigned int run_filter(struct sk_buff *skb, struct sock *sk,
+static inline unsigned int run_filter(const struct sk_buff *skb,
+                                      const struct sock *sk,
                                       unsigned int res)
 {
         struct sk_filter *filter;
@@ -532,15 +533,15 @@ static inline unsigned int run_filter(struct sk_buff *skb, struct sock *sk,
 }
 
 /*
-   This function makes lazy skb cloning in hope that most of packets
-   are discarded by BPF.
-
-   Note tricky part: we DO mangle shared skb! skb->data, skb->len
-   and skb->cb are mangled. It works because (and until) packets
-   falling here are owned by current CPU. Output packets are cloned
-   by dev_queue_xmit_nit(), input packets are processed by net_bh
-   sequencially, so that if we return skb to original state on exit,
-   we will not harm anyone.
+ * This function makes lazy skb cloning in hope that most of packets
+ * are discarded by BPF.
+ *
+ * Note tricky part: we DO mangle shared skb! skb->data, skb->len
+ * and skb->cb are mangled. It works because (and until) packets
+ * falling here are owned by current CPU. Output packets are cloned
+ * by dev_queue_xmit_nit(), input packets are processed by net_bh
+ * sequencially, so that if we return skb to original state on exit,
+ * we will not harm anyone.
  */
 
 static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
@@ -566,11 +567,11 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
 
         if (dev->header_ops) {
                 /* The device has an explicit notion of ll header,
-                   exported to higher levels.
-
-                   Otherwise, the device hides datails of it frame
-                   structure, so that corresponding packet head
-                   never delivered to user.
+                 * exported to higher levels.
+                 *
+                 * Otherwise, the device hides details of its frame
+                 * structure, so that corresponding packet head is
+                 * never delivered to user.
                  */
                 if (sk->sk_type != SOCK_DGRAM)
                         skb_push(skb, skb->data - skb_mac_header(skb));