int bitmap_parse (const char __user * ubuf, unsigned int ubuflen, unsigned long * maskp, int nmaskbits);
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.