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.