Name
__change_bit — 
     Toggle a bit in memory
 
Synopsis
void __change_bit ( | long nr,  | 
|   | volatile unsigned long * addr); | 
 
Arguments
nr
     the bit to change
    
addr
     the address to start counting from
    
Description
   Unlike change_bit, this function is non-atomic and may be reordered.
   If it's called on the same region of memory simultaneously, the effect
   may be that only one operation succeeds.