In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to passing in the timer pointer explicitly.
Calculate the drive from the offset of the timer in the timer list.
Cc: Jiri Kosina <jikos@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Geliang Tang <geliangtang@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>