From: Cesar Eduardo Barros <cesarb@cesarb.net>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Russell King <linux@arm.linux.org.uk>,
Ralf Baechle <ralf@linux-mips.org>,
David Howells <dhowells@redhat.com>,
Koichi Yasutake <yasutake.koichi@jp.panasonic.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
"David S. Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH] Make kunmap_atomic() harder to misuse
Date: Mon, 31 May 2010 07:45:03 -0300 [thread overview]
Message-ID: <4C03932F.8000303@cesarb.net> (raw)
In-Reply-To: <201005311945.19784.rusty@rustcorp.com.au>
Em 31-05-2010 07:15, Rusty Russell escreveu:
> On Sun, 30 May 2010 01:12:56 pm Andrew Morton wrote:
>> On Fri, 28 May 2010 07:53:13 -0300 Cesar Eduardo Barros<cesarb@cesarb.net> wrote:
>>> +/* Prevent people trying to call kunmap_atomic() as if it were kunmap() */
>>> +struct __kunmap_atomic_dummy {};
>>> +#define kunmap_atomic(addr, idx) do { \
>>> + BUILD_BUG_ON( \
>>> + __builtin_types_compatible_p(typeof(addr), struct page *)&& \
>>> + !__builtin_types_compatible_p(typeof(addr), struct __kunmap_atomic_dummy *)); \
>>> + kunmap_atomic_notypecheck((addr), (idx)); \
>>> + } while (0)
>>
>> We have a little __same_type() helper for this. __must_be_array()
>> should be using it, too.
>
> Yep... but I think BUILD_BUG_ON(__same_type((addr), struct page *)); is
> sufficient; void * is not compatible in my quick tests here.
That is what I get for only reading the manual instead of testing :(
(I only tested the completed patch, not each step along the way.)
I will try it later today and make a new patch if it works as expected.
--
Cesar Eduardo Barros
cesarb@cesarb.net
cesar.barros@gmail.com
WARNING: multiple messages have this Message-ID (diff)
From: Cesar Eduardo Barros <cesarb@cesarb.net>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Russell King <linux@arm.linux.org.uk>,
Ralf Baechle <ralf@linux-mips.org>,
David Howells <dhowells@redhat.com>,
Koichi Yasutake <yasutake.koichi@jp.panasonic.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
"David S. Miller" <davem@davemloft.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH] Make kunmap_atomic() harder to misuse
Date: Mon, 31 May 2010 07:45:03 -0300 [thread overview]
Message-ID: <4C03932F.8000303@cesarb.net> (raw)
In-Reply-To: <201005311945.19784.rusty@rustcorp.com.au>
Em 31-05-2010 07:15, Rusty Russell escreveu:
> On Sun, 30 May 2010 01:12:56 pm Andrew Morton wrote:
>> On Fri, 28 May 2010 07:53:13 -0300 Cesar Eduardo Barros<cesarb@cesarb.net> wrote:
>>> +/* Prevent people trying to call kunmap_atomic() as if it were kunmap() */
>>> +struct __kunmap_atomic_dummy {};
>>> +#define kunmap_atomic(addr, idx) do { \
>>> + BUILD_BUG_ON( \
>>> + __builtin_types_compatible_p(typeof(addr), struct page *)&& \
>>> + !__builtin_types_compatible_p(typeof(addr), struct __kunmap_atomic_dummy *)); \
>>> + kunmap_atomic_notypecheck((addr), (idx)); \
>>> + } while (0)
>>
>> We have a little __same_type() helper for this. __must_be_array()
>> should be using it, too.
>
> Yep... but I think BUILD_BUG_ON(__same_type((addr), struct page *)); is
> sufficient; void * is not compatible in my quick tests here.
That is what I get for only reading the manual instead of testing :(
(I only tested the completed patch, not each step along the way.)
I will try it later today and make a new patch if it works as expected.
--
Cesar Eduardo Barros
cesarb@cesarb.net
cesar.barros@gmail.com
--
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next prev parent reply other threads:[~2010-05-31 10:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-28 10:53 [PATCH] Make kunmap_atomic() harder to misuse Cesar Eduardo Barros
2010-05-28 10:53 ` Cesar Eduardo Barros
2010-05-30 3:42 ` Andrew Morton
2010-05-30 3:42 ` Andrew Morton
2010-05-30 17:42 ` Cesar Eduardo Barros
2010-05-30 17:42 ` Cesar Eduardo Barros
2010-05-31 10:15 ` Rusty Russell
2010-05-31 10:15 ` Rusty Russell
2010-05-31 10:45 ` Cesar Eduardo Barros [this message]
2010-05-31 10:45 ` Cesar Eduardo Barros
2010-05-31 23:45 ` [PATCH v2] " Cesar Eduardo Barros
2010-05-31 23:45 ` Cesar Eduardo Barros
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