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From: Andrew Morton <akpm@linux-foundation.org>
To: Sasha Levin <levinsasha928@gmail.com>
Cc: torvalds@linux-foundation.org, peterz@infradead.org,
	mingo@elte.hu, hpa@zytor.com, tglx@linutronix.de,
	srivatsa.bhat@linux.vnet.ibm.com, linux-kernel@vger.kernel.org
Subject: Re: [RFC 2/3] sched: add type checks to for_each_cpu_mask()
Date: Fri, 20 Apr 2012 15:33:51 -0700	[thread overview]
Message-ID: <20120420153351.53085ed9.akpm@linux-foundation.org> (raw)
In-Reply-To: <1334441685-4438-3-git-send-email-levinsasha928@gmail.com>

On Sat, 14 Apr 2012 18:14:44 -0400
Sasha Levin <levinsasha928@gmail.com> wrote:

> Add type checks to assert that 'mask' is 'struct cpumask *'. This check
> would have detected the bug fixed in e3831ed ("sched: Fix incorrect usage
> of for_each_cpu_mask() in select_fallback_rq()"):
> 
> kernel/sched/core.c: In function 'select_fallback_rq':
> kernel/sched/core.c:1273:2: warning: comparison of distinct pointer types lacks a cast
> kernel/sched/core.c:1284:3: warning: comparison of distinct pointer types lacks a cast
> 
> ...
>
> @@ -809,6 +810,7 @@ int __next_cpu(int n, const cpumask_t *srcp);
>  #define next_cpu(n, src)	__next_cpu((n), &(src))
>  #define any_online_cpu(mask) cpumask_any_and(&mask, cpu_online_mask)
>  #define for_each_cpu_mask(cpu, mask)			\
> +	typecheck(struct cpumask *, (mask));		\
>  	for ((cpu) = -1;				\
>  		(cpu) = next_cpu((cpu), (mask)),	\
>  		(cpu) < NR_CPUS; )

and int __next_cpu(int n, const cpumask_t *srcp);

I'm mystified.  Why didn't the next_cpu() call generate a warning when
passed the wrong type?

  parent reply	other threads:[~2012-04-20 22:33 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-14 22:14 [RFC 0/3] Extend type checking macros Sasha Levin
2012-04-14 21:02 ` Peter Zijlstra
2012-04-14 21:18 ` Srivatsa S. Bhat
2012-04-14 22:31   ` Srivatsa S. Bhat
2012-04-14 22:14 ` [RFC 1/3] typecheck: extend typecheck.h with more useful typechecking macros Sasha Levin
2012-04-14 21:12   ` Linus Torvalds
2012-04-14 22:14 ` [RFC 2/3] sched: add type checks to for_each_cpu_mask() Sasha Levin
2012-04-14 21:15   ` Linus Torvalds
2012-04-20 22:33   ` Andrew Morton [this message]
2012-04-14 22:14 ` [RFC 3/3] kernel.h: use new typechecking macros in min()/max() and friends Sasha Levin
2012-04-14 21:01   ` Peter Zijlstra
2012-04-14 21:17   ` Linus Torvalds

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