Re: [RFC][PATCH 1/2] x86, fpu: wrap get_xsave_addr() to make it safer
From: Oleg Nesterov
Date: Fri Jan 30 2015 - 13:29:28 EST
On 01/30, Dave Hansen wrote:
>
> +void *tsk_get_xsave_field(struct task_struct *tsk, int xsave_field)
> +{
> + union thread_xstate *xstate;
> +
> + unlazy_fpu(tsk);
ack, but to remind this depends on 2/3 I sent.
> + xstate = tsk->thread.fpu.state;
> + /*
> + * This might be unallocated if the FPU
> + * was never in use.
> + */
> + if (!xstate)
> + return NULL;
This is cosmetic, unlazy_fpu() is safe if !xstate, __thread_has_fpu()
is not possible in this case.
But perhaps
if (!used_math())
return NULL;
will look better.
Oleg.
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