Matthew Wilcox [off-list ref] wrote:

You've misunderstood the purpose of memfill.  memfill allows the caller
to specify a pattern which is not a single byte in size, eg memfill(addr,
0x12345678, 64) would result in 0x12345678 being reproduced 16 times.
memset(addr, 0x12345678, 64) would result in 0x78 being reproduced
64 times.

Ah.  Should it take a unsigned int rather than an unsigned long?

David