linux-kernel - Re: [PATCH v2] ACPI: NFIT: Fix local use of devm

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Message-ID: <652978deafdf8_f8792944c@dwillia2-mobl3.amr.corp.intel.com.notmuch>
Date:   Fri, 13 Oct 2023 10:05:34 -0700
From:   Dan Williams <dan.j.williams@...el.com>
To:     "Wilczynski, Michal" <michal.wilczynski@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        <nvdimm@...ts.linux.dev>, <linux-acpi@...r.kernel.org>
CC:     <rafael@...nel.org>, <vishal.l.verma@...el.com>, <lenb@...nel.org>,
        <dave.jiang@...el.com>, <ira.weiny@...el.com>,
        <linux-kernel@...r.kernel.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>
Subject: Re: [PATCH v2] ACPI: NFIT: Fix local use of devm_*()

Wilczynski, Michal wrote:
> On 10/13/2023 6:38 PM, Dan Williams wrote:
> > Michal Wilczynski wrote:
> >> devm_*() family of functions purpose is managing memory attached to a
> >> device. So in general it should only be used for allocations that should
> >> last for the whole lifecycle of the device. 
> > No, this assertion is not accurate, if it were strictly true then
> > devm_kfree() should be deleted. This patch is only a cleanup to switch
> > the automatic cleanup pattern from devm to the new cleanup.h helpers.
> 
> The memory in question is only used locally in a function, so there is no reason
> to use devm_*() family of functions. I think devm_kfree() is more for special
> cases where the memory is meant to be used for the whole lifecycle of device,
> but some special case occurs and it's not and it needs to be freed.
> 
> This is an incorrect API usage. Would you propose to change all memory
> allocations currently being done to devm_*() family simply because devm_kfree()
> exists ?

Michal, please work with someone else to get these cleanups upstream, I
am done with this thread.