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Subject: Re: [PATCH] Make math_state_restore() save and restore the interrupt flag
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Sat, 01 Feb 2014 17:43:57 -0800
To: Suresh Siddha <sbsiddha@gmail.com>
CC: Linus Torvalds <torvalds@linux-foundation.org>,
	Nate Eldredge <nate@thatsmathematics.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	stable <stable@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Maarten Baert <maarten-baert@hotmail.com>,
	Jan Kara <jack@suse.cz>, George Spelvin <linux@horizon.com>,
	Pekka Riikonen <priikone@iki.fi>
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What does the inner if clause do? It looks like it returns either way...

On February 1, 2014 5:35:13 PM PST, Suresh Siddha <sbsiddha@gmail.com> wrote:
>On Sat, Feb 1, 2014 at 5:26 PM, H. Peter Anvin <hpa@zytor.com> wrote:
>> Even "b" does that, no?
>
>oh right. It needs an else. only for non-eager fpu case we should do
>stts()
>
>  void __kernel_fpu_end(void)
>  {
>          if (use_eager_fpu()) {
>                  struct task_struct *me = current;
>
>                 if (tsk_used_math(me) && likely(!restore_fpu_checking(
>me)))
>                          return;
>          } else
>                  stts();
>  }
>
>thanks,
>suresh
>
>> "a" should be fine as long as we don't ever use
>> those features in the kernel, even under kernel_fpu_begin/end().

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