__bitmap_parse — convert an ASCII hex string into a bitmap.
| int __bitmap_parse ( | const char * buf, | 
| unsigned int buflen, | |
| int is_user, | |
| unsigned long * maskp, | |
| int nmaskbits ); | 
bufpointer to buffer containing string.
buflenbuffer size in bytes. If string is smaller than this then it must be terminated with a \0.
is_userlocation of buffer, 0 indicates kernel space
maskppointer to bitmap array that will contain result.
nmaskbitssize of bitmap, in bits.
   Commas group hex digits into chunks.  Each chunk defines exactly 32
   bits of the resultant bitmask.  No chunk may specify a value larger
   than 32 bits (-EOVERFLOW), and if a chunk specifies a smaller value
   then leading 0-bits are prepended.  -EINVAL is returned for illegal
   characters and for grouping errors such as “1,,5”, “,44”, “,” and "".
   Leading and trailing whitespace accepted, but not embedded whitespace.