linux-kernel - Re: [PATCH 1/11] Add generic helpers for arch IPI function calls

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Message-ID: <20080422145105.GJ12774@kernel.dk>
Date:	Tue, 22 Apr 2008 16:51:06 +0200
From:	Jens Axboe <jens.axboe@...cle.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
	npiggin@...e.de
Subject: Re: [PATCH 1/11] Add generic helpers for arch IPI function calls

On Tue, Apr 22 2008, Linus Torvalds wrote:
> 
> 
> On Tue, 22 Apr 2008, Jens Axboe wrote:
> > +
> > +static inline void csd_flag_wait(struct call_single_data *data)
> > +{
> > +	/* Wait for response */
> > +	do {
> > +		/*
> > +		 * We need to see the flags store in the IPI handler
> > +		 */
> > +		smp_mb();
> > +		if (!(data->flags & CSD_FLAG_WAIT))
> > +			break;
> > +		cpu_relax();
> > +	} while (1);
> > +}
> 
> You forgot to free the "data" here? The waiter must also free the object, 
> since now the callee does not.

The ipi interrupt handler does that, see kfree() in
generic_smp_call_function_single_interrupt() or call_func_data_free() in
generic_smp_call_function_interrupt().

-- 
Jens Axboe

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