bpf, xdp: constify some bpf_prog * function arguments

In lots of places, bpf_prog pointer is used only for tracing or other
stuff that doesn't modify the structure itself. Same for net_device.
Address at least some of them and add `const` attributes there. The
object code didn't change, but that may prevent unwanted data
modifications and also allow more helpers to have const arguments.

Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 15 insertions, 14 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index eaee2a819f4c..ec3acb16359e 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2591,10 +2591,10 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_frame *xdpf,
 int dev_map_enqueue_multi(struct xdp_frame *xdpf, struct net_device *dev_rx,
 			  struct bpf_map *map, bool exclude_ingress);
 int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,
-			     struct bpf_prog *xdp_prog);
+			     const struct bpf_prog *xdp_prog);
 int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
-			   struct bpf_prog *xdp_prog, struct bpf_map *map,
-			   bool exclude_ingress);
+			   const struct bpf_prog *xdp_prog,
+			   struct bpf_map *map, bool exclude_ingress);
 
 void __cpu_map_flush(struct list_head *flush_list);
 int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf,
@@ -2864,15 +2864,15 @@ struct sk_buff;
 
 static inline int dev_map_generic_redirect(struct bpf_dtab_netdev *dst,
 					   struct sk_buff *skb,
-					   struct bpf_prog *xdp_prog)
+					   const struct bpf_prog *xdp_prog)
 {
 	return 0;
 }
 
 static inline
 int dev_map_redirect_multi(struct net_device *dev, struct sk_buff *skb,
-			   struct bpf_prog *xdp_prog, struct bpf_map *map,
-			   bool exclude_ingress)
+			   const struct bpf_prog *xdp_prog,
+			   struct bpf_map *map, bool exclude_ingress)
 {
 	return 0;
 }
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 3a21947f2fd4..9a5d23ae3855 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1179,17 +1179,18 @@ static inline int xdp_ok_fwd_dev(const struct net_device *fwd,
  * This does not appear to be a real limitation for existing software.
  */
 int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
-			    struct xdp_buff *xdp, struct bpf_prog *prog);
+			    struct xdp_buff *xdp, const struct bpf_prog *prog);
 int xdp_do_redirect(struct net_device *dev,
 		    struct xdp_buff *xdp,
-		    struct bpf_prog *prog);
+		    const struct bpf_prog *prog);
 int xdp_do_redirect_frame(struct net_device *dev,
 			  struct xdp_buff *xdp,
 			  struct xdp_frame *xdpf,
-			  struct bpf_prog *prog);
+			  const struct bpf_prog *prog);
 void xdp_do_flush(void);
 
-void bpf_warn_invalid_xdp_action(struct net_device *dev, struct bpf_prog *prog, u32 act);
+void bpf_warn_invalid_xdp_action(const struct net_device *dev,
+				 const struct bpf_prog *prog, u32 act);
 
 #ifdef CONFIG_INET
 struct sock *bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ecc686409161..ecca21387a68 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3958,9 +3958,9 @@ static inline void dev_consume_skb_any(struct sk_buff *skb)
 }
 
 u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp,
-			     struct bpf_prog *xdp_prog);
-void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog);
-int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb);
+			     const struct bpf_prog *xdp_prog);
+void generic_xdp_tx(struct sk_buff *skb, const struct bpf_prog *xdp_prog);
+int do_xdp_generic(const struct bpf_prog *xdp_prog, struct sk_buff **pskb);
 int netif_rx(struct sk_buff *skb);
 int __netif_rx(struct sk_buff *skb);
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 58009fa66102..95452d1a07fc 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3627,7 +3627,7 @@ static inline netmem_ref skb_frag_netmem(const skb_frag_t *frag)
 int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb,
 		    unsigned int headroom);
 int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
-			 struct bpf_prog *prog);
+			 const struct bpf_prog *prog);
 
 /**
  * skb_frag_address - gets the address of the data contained in a paged fragment