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From: Andrew Morton <akpm@linux-foundation.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Jesper Juhl <jj@chaosbits.net>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Michel Lespinasse <walken@google.com>,
	Hugh Dickins <hughd@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH] Put braces around potentially empty 'if' body in handle_pte_fault()
Date: Mon, 19 Dec 2011 14:03:38 -0800	[thread overview]
Message-ID: <20111219140338.a05bd83d.akpm@linux-foundation.org> (raw)
In-Reply-To: <20111218011828.GA4445@p183.telecom.by>

On Sun, 18 Dec 2011 04:18:28 +0300
Alexey Dobriyan <adobriyan@gmail.com> wrote:

> On Sun, Dec 18, 2011 at 12:34:19AM +0000, Al Viro wrote:
> > On Sun, Dec 18, 2011 at 01:18:55AM +0100, Eric Dumazet wrote:
> > > Thats should be fixed in the reverse way :
> > > 
> > > #define flush_tlb_fix_spurious_fault(vma, address) do { } while (0)
> > 
> > There's a better way to do that -
> > #define f(a) do { } while(0)
> > does not work as a function returning void -
> > 	f(1), g();
> > won't work.  OTOH
> > #define f(a) ((void)0)
> > works just fine.
> 
> Two words: static inline.

Amen.  How often must we teach ourselves this lesson?


It gets a bit messy because of:

#ifndef flush_tlb_fix_spurious_fault
#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
#endif

But that can be handled with

static inline void flush_tlb_fix_spurious_fault(...)
{
	...
}
#define flush_tlb_fix_spurious_fault flush_tlb_fix_spurious_fault

and

#ifndef flush_tlb_fix_spurious_fault
static inline void flush_tlb_fix_spurious_fault(...)
{
}
#define flush_tlb_fix_spurious_fault flush_tlb_fix_spurious_fault
#endif

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WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Jesper Juhl <jj@chaosbits.net>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Michel Lespinasse <walken@google.com>,
	Hugh Dickins <hughd@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH] Put braces around potentially empty 'if' body in handle_pte_fault()
Date: Mon, 19 Dec 2011 14:03:38 -0800	[thread overview]
Message-ID: <20111219140338.a05bd83d.akpm@linux-foundation.org> (raw)
In-Reply-To: <20111218011828.GA4445@p183.telecom.by>

On Sun, 18 Dec 2011 04:18:28 +0300
Alexey Dobriyan <adobriyan@gmail.com> wrote:

> On Sun, Dec 18, 2011 at 12:34:19AM +0000, Al Viro wrote:
> > On Sun, Dec 18, 2011 at 01:18:55AM +0100, Eric Dumazet wrote:
> > > Thats should be fixed in the reverse way :
> > > 
> > > #define flush_tlb_fix_spurious_fault(vma, address) do { } while (0)
> > 
> > There's a better way to do that -
> > #define f(a) do { } while(0)
> > does not work as a function returning void -
> > 	f(1), g();
> > won't work.  OTOH
> > #define f(a) ((void)0)
> > works just fine.
> 
> Two words: static inline.

Amen.  How often must we teach ourselves this lesson?


It gets a bit messy because of:

#ifndef flush_tlb_fix_spurious_fault
#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
#endif

But that can be handled with

static inline void flush_tlb_fix_spurious_fault(...)
{
	...
}
#define flush_tlb_fix_spurious_fault flush_tlb_fix_spurious_fault

and

#ifndef flush_tlb_fix_spurious_fault
static inline void flush_tlb_fix_spurious_fault(...)
{
}
#define flush_tlb_fix_spurious_fault flush_tlb_fix_spurious_fault
#endif

  reply	other threads:[~2011-12-19 22:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-18  0:03 [PATCH] Put braces around potentially empty 'if' body in handle_pte_fault() Jesper Juhl
2011-12-18  0:03 ` Jesper Juhl
2011-12-18  0:18 ` Eric Dumazet
2011-12-18  0:18   ` Eric Dumazet
2011-12-18  0:26   ` Jesper Juhl
2011-12-18  0:26     ` Jesper Juhl
2011-12-18  0:34   ` Al Viro
2011-12-18  0:34     ` Al Viro
2011-12-18  1:18     ` Alexey Dobriyan
2011-12-18  1:18       ` Alexey Dobriyan
2011-12-19 22:03       ` Andrew Morton [this message]
2011-12-19 22:03         ` Andrew Morton

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