linux-kernel - Re: [PATCH v1 1/1] irqdomain: Refactor error path in __irq_domain_alloc

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Date:   Fri, 4 Aug 2023 23:12:11 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Marc Zyngier <maz@...nel.org>
Cc:     Johan Hovold <johan+linaro@...nel.org>,
        linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v1 1/1] irqdomain: Refactor error path in
 __irq_domain_alloc_fwnode()

On Fri, Aug 04, 2023 at 06:33:07PM +0100, Marc Zyngier wrote:
> On 2023-08-04 17:49, Andy Shevchenko wrote:
> > First of all, there is no need to call kasprintf() if the previous
> > allocation failed. Second, there is no need to call for kfree()
> > when we know that its parameter is NULL. Refactor the code accordingly.

...

> >  		n = kasprintf(GFP_KERNEL, "irqchip@%pa", pa);
> >  		break;
> >  	}
> > -
> > -	if (!fwid || !n) {
> > +	if (!n) {
> >  		kfree(fwid);
> > -		kfree(n);
> >  		return NULL;
> >  	}
> 
> What are you trying to fix?

I'm not trying to fix anything (there is no such statement from me),
but I would think of some micro-optimization (speedup boot for
unnoticeable time? Dunno.).

> We have a common error handling path, which makes it easy to
> track the memory management. I don't think this sort of bike
> shedding adds much to the maintainability of this code.

Your call, of course, but I not often see in the kernel two or three attempts
to allocate some memory and have grouped check for the failure.

> Now if you have spotted an actual bug, I'm all ears.

-- 
With Best Regards,
Andy Shevchenko