Name
change_bit — 
     Toggle a bit in memory
 
Synopsis
| void change_bit ( | long nr, | 
|  | volatile unsigned long * addr ); | 
 
Arguments
- nr
- 
     Bit to change
     
- addr
- 
     Address to start counting from
     
Description
   change_bit is atomic and may not be reordered.
   Note that nr may be almost arbitrarily large; this function is not
   restricted to acting on a single-word quantity.