linux-kernel - Re: [PATCH v8] firmware: google: Implement cbmem in sysfs driver

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Message-ID: <YvqyM3n48Q/0i9XZ@chromium.org>
Date:   Mon, 15 Aug 2022 14:53:07 -0600
From:   Jack Rosenthal <jrosenth@...omium.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Tzung-Bi Shih <tzungbi@...nel.org>,
        Guenter Roeck <groeck@...omium.org>,
        Julius Werner <jwerner@...omium.org>
Subject: Re: [PATCH v8] firmware: google: Implement cbmem in sysfs driver

Thanks for the detailed review!

On 2022-08-09 at 20:49 -0500, Stephen Boyd wrote:
> /sys/firmware/coreboot/cbmem?

Fixed in v9.

> > +#include <linux/ctype.h>
> 
> What is used from this header?

Not used, fixed in v9.

> Are all entries supposed to be writeable? Are there entries that are
> read-only?

The idea here was that we could use crossystem to update the cbmem entry
when it makes changes, however, I do see this as an odd usage of the
ABI, and in v9, I removed writing entirely and all entries are now
read-only.

If tools like crossystem need to maintain changes to this buffer, they
should either maintain that copy themselves in /run or something, or
daemonize and keep it in their process' memory.

> > +       return cbmem_entry_setup(entry);
> 
> Is there a reason this isn't inlined here?

cbmem_entry_setup was already a little long, so I just did this for
reading clarity.  If you think it would be clearer just inlined here, I
can change it (let me know).

> Need to set .owner = THIS_MODULE unless you use
> module_coreboot_driver().

Done.

> > +       if (!coreboot_kobj)
> 
> cbmem_kobj?

Done.