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Date: Sun, 24 Mar 2024 10:19:06 +0900
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Subject: Re: [PATCH] powerpc: ps3: mark ps3_notification_device static for
 stack usage
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To: Arnd Bergmann <arnd@arndb.de>, Geert Uytterhoeven <geert@linux-m68k.org>,
 Arnd Bergmann <arnd@kernel.org>
Cc: llvm@lists.linux.dev, Kevin Hao <haokexin@gmail.com>,
 "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
 Nick Desaulniers <ndesaulniers@google.com>, linux-kernel@vger.kernel.org,
 Nathan Chancellor <nathan@kernel.org>, Nicholas Piggin <npiggin@gmail.com>,
 Justin Stitt <justinstitt@google.com>,
 "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>, linuxppc-dev@lists.ozlabs.org,
 Bill Wendling <morbo@google.com>
References: <20240320180333.151043-1-arnd@kernel.org>
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From: Geoff Levand <geoff@infradead.org>
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On 3/23/24 05:24, Arnd Bergmann wrote:
> On Fri, Mar 22, 2024, at 09:34, Geoff Levand wrote:
>> On 3/21/24 17:32, Geert Uytterhoeven wrote:
>>> --- a/arch/powerpc/platforms/ps3/device-init.c
>>>> +++ b/arch/powerpc/platforms/ps3/device-init.c
>>>> @@ -770,7 +770,7 @@ static struct task_struct *probe_task;
>>>>
>>>>  static int ps3_probe_thread(void *data)
>>>>  {
>>>> -       struct ps3_notification_device dev;
>>>> +       static struct ps3_notification_device dev;
>>>>         int res;
>>>>         unsigned int irq;
>>>>         u64 lpar;
>>>
>>> Making it static increases kernel size for everyone.  So I'd rather
>>> allocate it dynamically. The thread already allocates a buffer, which
>>> can be replaced at no cost by allocating a structure containing both
>>> the ps3_notification_device and the buffer.
> 
> I didn't think it mattered much, given that you would rarely
> have a kernel with PS3 support along with other platforms.
> 
> I suppose it does increase the size for a PS3-only kernel
> as well, while your version makes it smaller.
> 
>> Here's what I came up with.  It builds for me without warnings.
>> I haven't tested it yet.  A review would be appreciated.
> 
> It seems a little complicated but looks all correct to
> me and reduces both stack and .data size, so
> 
> Acked-by: Arnd Bergmann <arnd@arndb.de>

Thanks Arnd.  I also thought it was a bit too much.  I made a simpler
version that I'll post as a separate message.

-Geoff