[PATCH] Use 'do {} while (0)' for empty flush_tlb_fix_spurious_fault() macro

[PATCH] Use 'do {} while (0)' for empty flush_tlb_fix_spurious_fault() macro

[Jesper Juhl]

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If one builds the kernel with -Wempty-body one gets this warning:

  mm/memory.c:3432:46: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]

due to the fact that 'flush_tlb_fix_spurious_fault' is a macro that
can sometimes be defined to nothing.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
 arch/x86/include/asm/pgtable.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 18601c8..ebe7e76 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -703,7 +703,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm,
 	pte_update(mm, addr, ptep);
 }
 
-#define flush_tlb_fix_spurious_fault(vma, address)
+#define flush_tlb_fix_spurious_fault(vma, address) do {} while (0)
 
 #define mk_pmd(page, pgprot)   pfn_pmd(page_to_pfn(page), (pgprot))
 
-- 
1.7.8


-- 
Jesper Juhl <jj@chaosbits.net>       http://www.chaosbits.net/
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Re: [PATCH] Use 'do {} while (0)' for empty flush_tlb_fix_spurious_fault() macro

[Michel Lespinasse]

On Sat, Dec 17, 2011 at 4:32 PM, Jesper Juhl <jj@chaosbits.net> wrote:
> If one builds the kernel with -Wempty-body one gets this warning:
>
>  mm/memory.c:3432:46: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
>
> due to the fact that 'flush_tlb_fix_spurious_fault' is a macro that
> can sometimes be defined to nothing.
>
> Signed-off-by: Jesper Juhl <jj@chaosbits.net>

Looks good to me. I'd be happy with either that or Al's alternative suggestion.

Reviewed-by: Michel Lespinasse <walken@google.com>

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.

Re: [PATCH] Use 'do {} while (0)' for empty flush_tlb_fix_spurious_fault() macro

[Jesper Juhl]

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On Sat, 17 Dec 2011, Michel Lespinasse wrote:

> On Sat, Dec 17, 2011 at 4:32 PM, Jesper Juhl <jj@chaosbits.net> wrote:
> > If one builds the kernel with -Wempty-body one gets this warning:
> >
> >  mm/memory.c:3432:46: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
> >
> > due to the fact that 'flush_tlb_fix_spurious_fault' is a macro that
> > can sometimes be defined to nothing.
> >
> > Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> 
> Looks good to me. I'd be happy with either that or Al's alternative suggestion.
> 
> Reviewed-by: Michel Lespinasse <walken@google.com>
> 
Thanks for the review.

I did see Al's suggestion and he does have a point. But since it doesn't 
actually matter much in this specific case I'd say "let's just go with 
this one - it matches what's done nearly everywhere else".
But, If someone disagrees strongly I'll cook up a different patch. :-)

-- 
Jesper Juhl <jj@chaosbits.net>       http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
Plain text mails only, please.

[tip:x86/cleanups] x86: Use "do { } while(0)" for empty flush_tlb_fix_spurious_fault() macro

[tip-bot for Jesper Juhl]

Commit-ID:  2ac13462b6d242684996e88a07fbed6dec6af622
Gitweb:     http://git.kernel.org/tip/2ac13462b6d242684996e88a07fbed6dec6af622
Author:     Jesper Juhl <jj@chaosbits.net>
AuthorDate: Sun, 18 Dec 2011 01:32:09 +0100
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 18 Dec 2011 09:14:18 +0100

x86: Use "do { } while(0)" for empty flush_tlb_fix_spurious_fault() macro

If one builds the kernel with -Wempty-body one gets this
warning:

  mm/memory.c:3432:46: warning: suggest braces around empty body in an ¡if¢ statement [-Wempty-body]

due to the fact that 'flush_tlb_fix_spurious_fault' is a macro
that can sometimes be defined to nothing.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: linux-mm@kvack.org
Cc: Michel Lespinasse <walken@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1112180128070.21784@swampdragon.chaosbits.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/include/asm/pgtable.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 18601c8..49afb3f 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -703,7 +703,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm,
 	pte_update(mm, addr, ptep);
 }
 
-#define flush_tlb_fix_spurious_fault(vma, address)
+#define flush_tlb_fix_spurious_fault(vma, address) do { } while (0)
 
 #define mk_pmd(page, pgprot)   pfn_pmd(page_to_pfn(page), (pgprot))