c - how to reuse the variable in linux kernel? -

extern unsigned long current_rx_time; export_symbol(current_rx_time); int netif_rx(struct sk_buff *skb)  {  current_rx_time = jiffies;  } 

i modified kernel source code in dev.c shown above. later creating loadable kernel module in procfs , using currentrx_time send user space shown below :

static int my_proc_show(struct seq_file *m, void *v) {     //i printing value below      seq_printf(m, "%lu\n", current_rx_time *1000/hz);      return 0; } 

but getting error when compile module above current_rx_time undeclared. tell me how solve problem?

first need declare variable , can export it.

so declare in dev.c

unsigned long current_rx_time; 

then export in dev.c

export_symbol(current_rx_time); 

and in other loadable module want use (let's in temp2.c)...

extern unsigned long current_rx_time; 

now make sure when going compile temp2.c @ time dev.c getting compile.