On 01/29, Rik van Riel wrote:
>
> The functions save_init_fpu and unlazy_fpu do essentially the
> same thing:
Yes ;) Could you look at 1-3 I sent ?
> Callers of init_fpu do want __thread_fpu_end, so move the call to
> __thread_fpu_end into init_fpu.
I don't think so... Contrary, I think this __thread_fpu_end() is simply
wrong.
> static inline void save_init_fpu(struct task_struct *tsk)
> {
> - WARN_ON_ONCE(!__thread_has_fpu(tsk));
> -
> - if (use_eager_fpu()) {
> - __save_fpu(tsk);
> - return;
> - }
> -
> preempt_disable();
> - __save_init_fpu(tsk);
> - __thread_fpu_end(tsk);
> + if (__thread_has_fpu(tsk)) {
> + if (use_eager_fpu())
> + __save_fpu(tsk);
> + else
> + __save_init_fpu(tsk);
See the changelog in 2/3. I think we still need __thread_fpu_end() if
__save_init_fpu() returns 0. In this case (_I think_) the state of FPU
doesn't match the saved state. IOW, "save_init" == "save" + "init" (I guess),
and that "init" can (say) reset some control register to default value.
> + } else if (!use_eager_fpu())
> + tsk->thread.fpu_counter = 0;
See 1/3, I think this should be simply removed.
> @@ -245,8 +233,10 @@ int init_fpu(struct task_struct *tsk)
> int ret;
>
> if (tsk_used_math(tsk)) {
> - if (cpu_has_fpu && tsk == current)
> - unlazy_fpu(tsk);
> + if (cpu_has_fpu && tsk == current) {
> + save_init_fpu(tsk);
> + __thread_fpu_end(tsk);
See above.
Oleg.
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