Re: [PATCH 1/1] x86/cpu: kill eager_fpu_init_bp()

Borislav Petkov
2015-03-16T12:45:42Z

On Sat, Mar 14, 2015 at 04:13:34PM +0100, Oleg Nesterov wrote:
> Now that eager_fpu_init_bp() does setup_init_fpu_buf() and nothing else
> we can remove it and move this code into its "caller", eager_fpu_init().
>
> This avoids the confusing games with "static __refdata void (*boot_func)".
> init_xstate_buf can be NULL only on boot, so it is safe to the "__init"
> setup_init_fpu_buf() function, just we need to add the "__init_refok"
> marker.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Applied, thanks.

I added a note above eager_fpu_init() why it is marked as __init_refok:

---
From: Oleg Nesterov <oleg@redhat.com>
Date: Sat, 14 Mar 2015 16:13:34 +0100
Subject: [PATCH] x86/fpu: Kill eager_fpu_init_bp()

Now that eager_fpu_init_bp() does setup_init_fpu_buf() only and
nothing else, we can remove it and move this code into its "caller",
eager_fpu_init().

This avoids the confusing games with "static __refdata void (*boot_func)":

init_xstate_buf can be NULL only during boot, so it is safe to call the
__init-annotated setup_init_fpu_buf() function in eager_fpu_init(), we
just need to mark it as __init_refok.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Link: http://lkml.kernel.org/r/20150314151334.GC13029@redhat.com
Signed-off-by:
---
arch/x86/kernel/xsave.c | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index ada8df7b89c0..87a815b85f3e 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -678,16 +678,12 @@ void xsave_init(void)
this_func();
}

-static inline void __init eager_fpu_init_bp(void)
-{
- if (!init_xstate_buf)
- setup_init_fpu_buf();
-}
-
-void eager_fpu_init(void)
+/*
+ * setup_init_fpu_buf() is __init and it is OK to call it here because
+ * init_xstate_buf will be unset only once during boot.
+ */
+void __init_refok eager_fpu_init(void)
{
- static __refdata void (*boot_func)(void) = eager_fpu_init_bp;
-
WARN_ON(used_math());
current_thread_info()->status = 0;

@@ -699,10 +695,8 @@ void eager_fpu_init(void)
return;
}

- if (boot_func) {
- boot_func();
- boot_func = NULL;
- }
+ if (!init_xstate_buf)
+ setup_init_fpu_buf();
}

/*
--
2.3.3

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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