gcc allows this when arg is a function, but sparse complains:
drivers/char/ipmi/ipmi_watchdog.c:303:1: error: cannot dereference this type
drivers/char/ipmi/ipmi_watchdog.c:307:1: error: cannot dereference this type
drivers/char/ipmi/ipmi_watchdog.c:311:1: error: cannot dereference this type
Reported-by: Randy Dunlap <randy.dunlap@oracle.com> Tested-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>