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Date:   Mon, 24 Oct 2022 16:22:53 -0700
From:   "Darrick J. Wong" <djwong@kernel.org>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     xfs <linux-xfs@vger.kernel.org>,
        Shiyang Ruan <ruansy.fnst@fujitsu.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [PATCH] xfs: fix incorrect return type for fsdax fault handlers
Message-ID: <Y1ceTY4clIYOsRqA@magnolia>
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On Mon, Oct 24, 2022 at 10:56:48PM +0100, Matthew Wilcox wrote:
> On Mon, Oct 24, 2022 at 02:32:18PM -0700, Darrick J. Wong wrote:
> > Fix the incorrect return type for these two functions, and make the
> > !fsdax version return SIGBUS since there is no vm_fault_t that maps to
> > zero.
> 
> Hmm?  You should be able to return 0 without sparse complaining.

What does (vm_fault_t)0 do?  And why wouldn't we want to induce a
segfault if someone calls the fsdax fault function when fsdax isn't
supported?

--D