module: make module_refcount() a signed integer.

James Bottomley points out that it will be -1 during unload.  It's
only used for diagnostics, so let's not hide that as it could be a
clue as to what's gone wrong.

Cc: Jason Wessel <>
Acked-and-documention-added-by: James Bottomley <>
Reviewed-by: Masami Hiramatsu <>
Signed-off-by: Rusty Russell <>
3 files changed