Re: [PATCH v2 1/2] driver: core: add dedicated workqueue for devlink removal

From: "Nuno Sá" <noname.nuno@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>, nuno.sa@analog.com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Daniel Scally <djrscally@gmail.com>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	 Len Brown <lenb@kernel.org>,
	linux-acpi@vger.kernel.org, devicetree@vger.kernel.org,
	 linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] driver: core: add dedicated workqueue for devlink removal
Date: Mon, 05 Feb 2024 15:32:04 +0100	[thread overview]
Message-ID: <31f7c989e9ee1eae49976466543f7192865775ff.camel@gmail.com> (raw)
In-Reply-To: <ZcDV9epWJf_oTCMK@smile.fi.intel.com>

On Mon, 2024-02-05 at 14:35 +0200, Andy Shevchenko wrote:
> On Mon, Feb 05, 2024 at 01:09:32PM +0100, Nuno Sa via B4 Relay wrote:
> > From: Nuno Sa <nuno.sa@analog.com>
> > 
> > Let's use a dedicated queue for devlinks since releasing a link happens
> > asynchronously but some code paths, like DT overlays, have some
> > expectations regarding the of_node when being removed (the refcount must
> > be 1). Given how devlinks are released that cannot be assured. Hence, add a
> > dedicated queue so that it's easy to sync against devlinks removal.
> > 
> > While at it, make sure to explicitly include <linux/workqueue.h>.
> 
> ...
> 
> > +++ b/include/linux/fwnode.h
> > @@ -213,5 +213,6 @@ extern bool fw_devlink_is_strict(void);
> >  int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup);
> >  void fwnode_links_purge(struct fwnode_handle *fwnode);
> >  void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode);
> > +void fwnode_links_flush_queue(void);
> 
> I am not sure if you have seen my comment against v1.
> 

I did received it like 30min ago...

> I find the namespace a bit messy for devlinks. And to me seems the best place
> for this line is to be before fwnode_links_purge().
> 

TBH, I'm not really keen on sending a v3 just for that (unless I'm asked otherwise).
But If I have (still missing DT guys feedback), I'll do as you suggested.

- Nuno Sá