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From: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel@savoirfairelinux.com,
	"David S. Miller" <davem@davemloft.net>,
	Florian Fainelli <f.fainelli@gmail.com>
Subject: Re: [PATCH net-next 4/8] net: dsa: mv88e6xxx: do not increment bus refcount
Date: Fri, 10 Jun 2016 15:59:22 -0400	[thread overview]
Message-ID: <87k2hwq0h1.fsf@ketchup.mtl.sfl> (raw)
In-Reply-To: <20160609023641.GJ2227@lunn.ch>

Hi,

Andrew Lunn <andrew@lunn.ch> writes:

> On Wed, Jun 08, 2016 at 08:44:52PM -0400, Vivien Didelot wrote:
>> The MDIO device probe and remove functions are respectively incrementing
>> and decrementing the bus refcount themselves. Since these bus level
>> actions are out of the device scope, remove them.
>
> I agree with the patch. But have you checked the mdio layer is doing
> the right thing? If not, we should fix that first.

So I added some printing after incrementing/decrementing the refcount in
get_device/put_device to track &ps->bus->dev, which name is "0.1".

Regardless having this patch or not, the refcount of the 0.1 mii_bus
device is 5 before loading the mv88e6xxx module on vf610-zii-dev-rev-b.

Below is a portion of dmesg:

    [    8.921647] get_device: 400d1000.etherne refcount: 4
    [    8.926225] get_device: 0.1 refcount: 2
    [    8.929561] get_device: mdio-mux refcount: 5
    [    8.934076] get_device: 0.1 refcount: 3
    [    8.937446] get_device: 0.1 refcount: 4
    [    8.940792] put_device: 0.1 refcount: 3
    [    8.944181] libphy: mdio_mux: probed
    [    8.947885] mdio_bus 0.1:00: mdio_device_register
    [    8.952649] get_device: 0.1:00 refcount: 2
    [    8.956283] get_device: 0.1 refcount: 4
    [    8.959838] get_device: 0.1:00 refcount: 3
    [    8.963991] get_device: 0.1:00 refcount: 4
    [    8.967598] put_device: 0.1:00 refcount: 3
    [    8.971298] get_device: 0.2 refcount: 2
    [    8.974687] get_device: mdio-mux refcount: 7

So it seems like of_ is managing the bus refcount on events such as a
new child node (0.1:00).

Thanks,

        Vivien

  reply	other threads:[~2016-06-10 19:59 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-09  0:44 [PATCH net-next 0/8] net: dsa: mv88e6xxx: misc probe improvements Vivien Didelot
2016-06-09  0:44 ` [PATCH net-next 1/8] net: dsa: mv88e6xxx: fix style issues Vivien Didelot
2016-06-09  2:22   ` Andrew Lunn
2016-06-09  0:44 ` [PATCH net-next 2/8] net: dsa: mv88e6xxx: remove redundant assignments Vivien Didelot
2016-06-09  2:30   ` Andrew Lunn
2016-06-09  0:44 ` [PATCH net-next 3/8] net: dsa: mv88e6xxx: use already declared variables Vivien Didelot
2016-06-09  2:31   ` Andrew Lunn
2016-06-09  0:44 ` [PATCH net-next 4/8] net: dsa: mv88e6xxx: do not increment bus refcount Vivien Didelot
2016-06-09  2:36   ` Andrew Lunn
2016-06-10 19:59     ` Vivien Didelot [this message]
2016-06-10 20:06       ` Andrew Lunn
2016-06-09  0:44 ` [PATCH net-next 5/8] net: dsa: mv88e6xxx: add switch register helpers Vivien Didelot
2016-06-09  2:39   ` Andrew Lunn
2016-06-09 12:53     ` Vivien Didelot
2016-06-09  0:44 ` [PATCH net-next 6/8] net: dsa: mv88e6xxx: add chip detection helper Vivien Didelot
2016-06-09  0:44 ` [PATCH net-next 7/8] net: dsa: mv88e6xxx: explicit compatible devices Vivien Didelot
2016-06-09  2:14   ` Andrew Lunn
2016-06-10 20:26     ` Vivien Didelot
2016-06-09  0:44 ` [PATCH net-next 8/8] net: dsa: mv88e6xxx: fail on mismatching probe Vivien Didelot
2016-06-09  2:21   ` Andrew Lunn
2016-06-10 20:32     ` Vivien Didelot

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