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From: Lukas Wunner <lukas@wunner.de>
To: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Eric Dumazet <edumazet@google.com>
Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org,
	Steve Glendinning <steve.glendinning@shawell.net>,
	UNGLinuxDriver@microchip.com, Oliver Neukum <oneukum@suse.com>,
	Andre Edich <andre.edich@microchip.com>,
	Oleksij Rempel <o.rempel@pengutronix.de>,
	Oleksij Rempel <linux@rempel-privat.de>,
	Martyn Welch <martyn.welch@collabora.com>,
	Gabriel Hojda <ghojda@yo2urs.ro>,
	Christoph Fritz <chf.fritz@googlemail.com>,
	Lino Sanfilippo <LinoSanfilippo@gmx.de>,
	Philipp Rosenberger <p.rosenberger@kunbus.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Ferry Toth <fntoth@gmail.com>, Andrew Lunn <andrew@lunn.ch>,
	Alan Stern <stern@rowland.harvard.edu>
Subject: [PATCH net-next v2 0/3] Deadlock no more in LAN95xx
Date: Fri, 1 Jul 2022 22:47:50 +0200	[thread overview]
Message-ID: <cover.1656707954.git.lukas@wunner.de> (raw)

Second attempt at fixing a runtime resume deadlock in the LAN95xx USB driver:

In short, the driver isn't using the "nopm" register accessors in portions
of its runtime resume path, causing a deadlock.  I'm fixing that by
auto-detecting whether nopm accessors shall be used, instead of
having to explicitly call them wherever it's necessary.
As a byproduct, code size shrinks significantly (see diffstat below).

Back in April I submitted a first attempt which was rejected by Alan Stern:
https://lore.kernel.org/all/6710d8c18ff54139cdc538763ba544187c5a0cee.1651041411.git.lukas@wunner.de/

That approach only detected whether a PM callback is running concurrently,
not whether the access is performed by the PM callback.  I've come up with
a different approach which should resolve the objection (see patch [1/3]).

Thanks!

Lukas Wunner (3):
  usbnet: smsc95xx: Fix deadlock on runtime resume
  usbnet: smsc95xx: Clean up nopm handling
  usbnet: smsc95xx: Clean up unnecessary BUG_ON() upon register access

 drivers/net/usb/smsc95xx.c | 202 ++++++++++++++++---------------------
 1 file changed, 86 insertions(+), 116 deletions(-)

-- 
2.36.1


             reply	other threads:[~2022-07-01 20:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-01 20:47 Lukas Wunner [this message]
2022-07-01 20:47 ` [PATCH net-next v2 1/3] usbnet: smsc95xx: Fix deadlock on runtime resume Lukas Wunner
2022-07-01 20:47 ` [PATCH net-next v2 2/3] usbnet: smsc95xx: Clean up nopm handling Lukas Wunner
2022-07-01 20:47 ` [PATCH net-next v2 3/3] usbnet: smsc95xx: Clean up unnecessary BUG_ON() upon register access Lukas Wunner
2022-07-04  9:50 ` [PATCH net-next v2 0/3] Deadlock no more in LAN95xx patchwork-bot+netdevbpf

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