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Date:   Wed, 14 Jun 2023 21:28:31 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Finn Thain <fthain@linux-m68k.org>
Cc:     Michael Schmitz <schmitzmic@gmail.com>,
        Martin Steigerwald <martin@lichtvoll.de>,
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        Christoph Hellwig <hch@infradead.org>,
        Joanne Dow <jdow@earthlink.net>
Subject: Re: [PATCH v7 2/2] block: add overflow checks for Amiga partition
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On Thu, Jun 15, 2023 at 10:13:14AM +1000, Finn Thain wrote:
> > affs_hardblocks.h is a UAPI header - what are the rules and 
> > ramifications around changes to those? Might not be worth the hassle in 
> > the end.
> > 
> 
> I think it's safe to fix the UAPI header if we are talking about 
> endianness annotations that affect static checking and not code 
> generation. The existing annotations in that struct would appear to 
> support that notion, if indeed they were put there for the benefit of the 
> kernel.

More importantly there has never been any API gurantee in the UAPI
headers.  Compiling user space code absolutely may break due to changes
to them (although we avoid that if we can), we just must not change the
kernel ABI.  But as as said the __be annotations are no-ops for
compilers, and do the right thing even in userspace for projects using
sparse.