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Date: Fri, 5 Jul 2024 16:07:59 +0200
From: Lukas Wunner <lukas@wunner.de>
To: Christoph Hellwig <hch@infradead.org>
Cc: Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>,
	linux-pci@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Ilpo Jarvinen <ilpo.jarvinen@linux.intel.com>,
	Keith Busch <kbusch@kernel.org>, Marek Behun <marek.behun@nic.cz>,
	Pavel Machek <pavel@ucw.cz>, Randy Dunlap <rdunlap@infradead.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Stuart Hayes <stuart.w.hayes@gmail.com>
Subject: Re: [PATCH v3 3/3] PCI/NPEM: Add _DSM PCIe SSD status LED management
Message-ID: <Zof-P7jNmoLvJTF-@wunner.de>
References: <20240705125436.26057-1-mariusz.tkaczyk@linux.intel.com>
 <20240705125436.26057-4-mariusz.tkaczyk@linux.intel.com>
 <ZofvZyzIe_7tH6zZ@infradead.org>
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In-Reply-To: <ZofvZyzIe_7tH6zZ@infradead.org>

On Fri, Jul 05, 2024 at 06:04:39AM -0700, Christoph Hellwig wrote:
> > +struct dsm_output {
> > +	u16 status;
> > +	u8 function_specific_err;
> > +	u8 vendor_specific_err;
> > +	u32 state;
> > +} __packed;
> 
> This structure is naturally aligned, so no need for the __packed.

Isn't the compiler free to insert padding wherever it sees fit?

structs passed to ACPI firmware would no longer comply with the
spec-prescribed layout then and declaring them __packed seems to be
the only way to ensure that doesn't happen.

Thanks,

Lukas