Re: [RFC PATCH 02/15] cxl/core/hdm: Bail on endpoint init fail

From: Dan Williams <dan.j.williams@intel.com>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Ben Widawsky <ben.widawsky@intel.com>,
	 Klaus Jensen <its@irrelevant.dk>, Josef Bacik <jbacik@fb.com>,
	 Adam Manzanares <a.manzanares@samsung.com>,
	 "linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
	Linux NVDIMM <nvdimm@lists.linux.dev>,
	 "patches@lists.linux.dev" <patches@lists.linux.dev>,
	Alison Schofield <alison.schofield@intel.com>,
	 Ira Weiny <ira.weiny@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>
Subject: Re: [RFC PATCH 02/15] cxl/core/hdm: Bail on endpoint init fail
Date: Wed, 18 May 2022 22:09:13 -0700	[thread overview]
Message-ID: <CAPcyv4hFHxc9wV1R_v70WdtZAyxD7oAV2HxxySF0nZx+vunM0Q@mail.gmail.com> (raw)
In-Reply-To: <Yn6yGKmMZES0IQbw@bombadil.infradead.org>

On Fri, May 13, 2022 at 12:32 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> On Fri, May 13, 2022 at 12:14:51PM -0700, Dan Williams wrote:
> > On Fri, May 13, 2022 at 8:12 AM Luis Chamberlain <mcgrof@kernel.org> wrote:
> > > But with CONFIG_FAIL_FUNCTION this means you don't have to open code
> > > should_fail() calls, but instead for each routine you want to add a failure
> > > injection support you'd just use ALLOW_ERROR_INJECTION() per call.
> >
> > So cxl_test takes the opposite approach and tries not to pollute the
> > production code with test instrumentation. All of the infrastructure
> > to replace calls and inject mocked values is self contained in
> > tools/testing/cxl/ where it builds replacement modules with test
> > instrumentation. Otherwise its a maintenance burden, in my view, to
> > read the error injection macros in the nominal code paths.
>
> Is relying on just ALLOW_ERROR_INJECTION() per routine you'd want
> to enable error injection for really too much to swallow?

Inline? To me, yes. However, it seems the perfect thing to hide
out-of-line in a mocked call injected from tools/testing/.