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Date: Fri, 7 Nov 2025 13:04:36 +0100
From: Christoph Hellwig <hch@lst.de>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Vlastimil Babka <vbabka@suse.cz>,
	Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@gentwo.org>,
	David Rientjes <rientjes@google.com>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Harry Yoo <harry.yoo@oracle.com>, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH 2/9] mempool: add error injection support
Message-ID: <20251107120436.GB30551@lst.de>
References: <20251031093517.1603379-1-hch@lst.de> <20251031093517.1603379-3-hch@lst.de> <20251107032900.GB16450@sol>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Thu, Nov 06, 2025 at 07:29:00PM -0800, Eric Biggers wrote:
> > +static DECLARE_FAULT_ATTR(fail_mempool_alloc);
> > +
> > +static int __init mempool_faul_inject_init(void)
> > +{
> > +	return PTR_ERR_OR_ZERO(fault_create_debugfs_attr("fail_mempool_alloc",
> > +			NULL, &fail_mempool_alloc));
> > +}
> > +late_initcall(mempool_faul_inject_init);
> 
> Initcalls usually go at the bottom of the file.

For a generic init function yes.  But given that this is only for error
injection, I'd rather keep the error injection handling in one spot.

> 
> > +	if (should_fail_ex(&fail_mempool_alloc, 1, FAULT_NOWARN)) {
> 
> This doesn't build when CONFIG_FAULT_INJECTION=n.

Yeah, the buildbot already told me.  For some reason there is a
!CONFIG_FAULT_INJECTION stube for should_fail_ex, but the flags are
not defined in that case.  I'll add another patch to the series to
fix it.