net: hide the definition of dev_get_by_napi_id()

There are no module callers of dev_get_by_napi_id(),
and commit d1cacd7 ("netdev: prevent accessing NAPI instances
from another namespace") proves that getting NAPI by id
needs to be done with care. So hide dev_get_by_napi_id().

Reviewed-by: Jacob Keller <[email protected]>
Reviewed-by: Kalesh AP <[email protected]>
Reviewed-by: Joe Damato <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

include/linux/netdevice.h

@@ -3252,7 +3252,6 @@ struct net_device *netdev_get_by_index(struct net *net, int ifindex,
 struct net_device *netdev_get_by_name(struct net *net, const char *name,
 				      netdevice_tracker *tracker, gfp_t gfp);
 struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex);
-struct net_device *dev_get_by_napi_id(unsigned int napi_id);
 void netdev_copy_name(struct net_device *dev, char *name);
 
 static inline int dev_hard_header(struct sk_buff *skb, struct net_device *dev,

net/core/dev.c

@@ -957,7 +957,6 @@ EXPORT_SYMBOL(netdev_get_by_index);
  *	its reference counter increased so the caller must be careful
  *	about locking. The caller must hold RCU lock.
  */
-
 struct net_device *dev_get_by_napi_id(unsigned int napi_id)
 {
 	struct napi_struct *napi;
@@ -971,7 +970,6 @@ struct net_device *dev_get_by_napi_id(unsigned int napi_id)
 
 	return napi ? napi->dev : NULL;
 }
-EXPORT_SYMBOL(dev_get_by_napi_id);
 
 static DEFINE_SEQLOCK(netdev_rename_lock);
 

net/core/dev.h

@@ -23,6 +23,7 @@ struct sd_flow_limit {
 extern int netdev_flow_limit_table_len;
 
 struct napi_struct *netdev_napi_by_id(struct net *net, unsigned int napi_id);
+struct net_device *dev_get_by_napi_id(unsigned int napi_id);
 
 #ifdef CONFIG_PROC_FS
 int __init dev_proc_init(void);

net/socket.c

@@ -110,6 +110,8 @@
 #include <linux/ptp_clock_kernel.h>
 #include <trace/events/sock.h>
 
+#include "core/dev.h"
+
 #ifdef CONFIG_NET_RX_BUSY_POLL
 unsigned int sysctl_net_busy_read __read_mostly;
 unsigned int sysctl_net_busy_poll __read_mostly;