vfree — 
     release memory allocated by vmalloc
 
| void vfree ( | const void * addr ); | 
   Free the virtually continuous memory area starting at addr, as
   obtained from vmalloc, vmalloc_32 or __vmalloc. If addr is
   NULL, no operation is performed.
   
   Must not be called in NMI context (strictly speaking, only if we don't
   have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling
   conventions for vfree arch-depenedent would be a really bad idea)