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Date:   Wed, 18 May 2022 11:03:45 -0500
From:   "Gustavo A. R. Silva" <gustavoars@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Lin Yujun <linyujun809@huawei.com>, mingo@redhat.com,
        acme@kernel.org, mark.rutland@arm.com,
        alexander.shishkin@linux.intel.com, jolsa@kernel.org,
        namhyung@kernel.org, tglx@linutronix.de, bp@alien8.de,
        dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        johnny.chenyi@huawei.com, chenjiahao16@huawei.com,
        chenlifu@huawei.com, lizhengyu3@huawei.com, liaochang1@huawei.com,
        wangzhu9@huawei.com, xuyihang@huawei.com, chris.zjh@huawei.com,
        zouyipeng@huawei.com
Subject: Re: [PATCH -next] x86/events:Use struct_size() helper in kzalloc()
Message-ID: <20220518160345.GA43938@embeddedor>
References: <20220518131626.109123-1-linyujun809@huawei.com>
 <20220518134920.GA8361@embeddedor>
 <YoT6tHWbBOchi29i@hirez.programming.kicks-ass.net>
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On Wed, May 18, 2022 at 03:55:00PM +0200, Peter Zijlstra wrote:
> On Wed, May 18, 2022 at 08:49:20AM -0500, Gustavo A. R. Silva wrote:
> 
> > > Signed-off-by: Lin Yujun <linyujun809@huawei.com>
> > > ---
> > >  arch/x86/events/rapl.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
> > > index 77e3a47af5ad..c7e79f0ac04f 100644
> > > --- a/arch/x86/events/rapl.c
> > > +++ b/arch/x86/events/rapl.c
> > > @@ -685,7 +685,7 @@ static int __init init_rapl_pmus(void)
> > >  	int maxdie = topology_max_packages() * topology_max_die_per_package();
> > >  	size_t size;
> > >  
> > > -	size = sizeof(*rapl_pmus) + maxdie * sizeof(struct rapl_pmu *);
> > > +	size = struct_size(rapl_pmus, pmus, maxdie);
> > >  	rapl_pmus = kzalloc(size, GFP_KERNEL);
> > 
> > It seems that in this case, size could be entirely replaced by
> > struct_size().
> 
> Except every time I look at struct_size() I go: WTF does that do; while
> the code as-is is crystal clear, no de-obfucstaion required.

Naming it flex_struct_size() would be more informative?

--
Gustavo