Re: [PATCH net-next] net: hide the definition of dev_get_by_napi_id()

[Jacob Keller <jacob.e.keller@intel.com>]

On 1/9/2025 4:49 PM, Jakub Kicinski wrote:
> There are no module callers of dev_get_by_napi_id(),
> and commit d1cacd747768 ("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().
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>

> ---
> CC: jdamato@fastly.com
> ---
>  include/linux/netdevice.h | 1 -
>  net/core/dev.c            | 2 --
>  net/core/dev.h            | 1 +
>  net/socket.c              | 2 ++
>  4 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 1812564b5204..aeb4a6cff171 100644
> --- a/include/linux/netdevice.h
> +++ b/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,
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 4452ca2c91ea..1a90ed8cc6cc 100644
> --- a/net/core/dev.c
> +++ b/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);
>  
> diff --git a/net/core/dev.h b/net/core/dev.h
> index 08812a025a9b..d8966847794c 100644
> --- a/net/core/dev.h
> +++ b/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);
> diff --git a/net/socket.c b/net/socket.c
> index 16402b8be5a7..4afe31656a2b 100644
> --- a/net/socket.c
> +++ b/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;