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From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <david@fromorbit.com>
Cc: Wilfred Mallawa <wilfred.opensource@gmail.com>,
	Carlos Maiolino <cem@kernel.org>,
	"Darrick J . Wong" <djwong@kernel.org>,
	linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
	Christoph Hellwig <hch@lst.de>,
	Wilfred Mallawa <wilfred.mallawa@wdc.com>
Subject: Re: [PATCH] xfs: add static size checks for structures in xfs_fs.h
Date: Mon, 9 Feb 2026 15:41:46 +0100	[thread overview]
Message-ID: <20260209144146.GA16995@lst.de> (raw)
In-Reply-To: <aYZquyDjPqZIcKe4@dread.disaster.area>

On Sat, Feb 07, 2026 at 09:27:07AM +1100, Dave Chinner wrote:
> Different architectures will have different padding, alignment and
> holes for the same structure (e.g. 32 bit vs 64 bit) resulting in
> different sizes for the same structure across different platforms.
> 
> This is not actually a bug in the UAPI - as long as the
> architecture's userspace and the kernel are using the same structure
> layout, variations in structure size and layout between architectures
> don't matter.

Except for the pointers it generally is a bug in the structure
defintion, and even for pointers the current consensus is moving
towards encoding them as a u64.  So yeah, this will have to skip
some of the older structures, but for anything newer it the right
thing to do, and will catch issues.


      parent reply	other threads:[~2026-02-09 14:41 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-06  3:05 [PATCH] xfs: add static size checks for structures in xfs_fs.h Wilfred Mallawa
2026-02-06  6:08 ` Christoph Hellwig
2026-02-09  7:04   ` Wilfred Mallawa
2026-02-09 14:47     ` hch
2026-02-10  5:59       ` Wilfred Mallawa
2026-02-06  9:39 ` kernel test robot
2026-02-06 11:02 ` kernel test robot
2026-02-06 18:03 ` kernel test robot
2026-02-06 22:27 ` Dave Chinner
2026-02-09  6:57   ` Wilfred Mallawa
2026-02-09 14:41   ` Christoph Hellwig [this message]

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