From: Sean Anderson <sean.anderson@seco.com>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] usb: ulpi: Call of_node_put correctly
Date: Tue, 25 Jan 2022 12:01:00 -0500 [thread overview]
Message-ID: <284ed076-ac57-c90c-751d-0ced6d0c7c61@seco.com> (raw)
In-Reply-To: <dc30490b-15e8-1b10-beb2-eaaa10190649@seco.com>
On 1/25/22 11:53 AM, Sean Anderson wrote:
> Hi Heikki,
>
> On 1/25/22 4:18 AM, Heikki Krogerus wrote:
>> On Mon, Jan 24, 2022 at 12:33:44PM -0500, Sean Anderson wrote:
>>> of_node_put should always be called on device nodes gotten from
>>> of_get_*. Additionally, it should only be called after there are no
>>> remaining users. To address the first issue, call of_node_put if later
>>> steps in ulpi_register fail. To address the latter, call of_node_put
>>> only after calling device_unregister.
>>
>> This looks like a fix, but you don't have the fix tag.
>
> You're right this should have
>
> Fixes: ef6a7bcfb01c ("usb: ulpi: Support device discovery via DT")
>
>>> Signed-off-by: Sean Anderson <sean.anderson@seco.com>
>>> ---
>>>
>>> Changes in v2:
>>> - New
>>>
>>> drivers/usb/common/ulpi.c | 10 +++++++---
>>> 1 file changed, 7 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
>>> index 87deb514eb78..c6ba72544f2b 100644
>>> --- a/drivers/usb/common/ulpi.c
>>> +++ b/drivers/usb/common/ulpi.c
>>> @@ -301,11 +301,11 @@ static int ulpi_register(struct device *dev, struct ulpi *ulpi)
>>>
>>> ret = ulpi_read_id(ulpi);
>>> if (ret)
>>> - return ret;
>>> + goto err;
>>>
>>> ret = device_register(&ulpi->dev);
>>> if (ret)
>>> - return ret;
>>> + goto err;
>>
>> I think there is another bug in the code here. Missing put_device().
>
> So what is the correct way to create a device? Shouldn't device_register
> be paired with device_unregister? And from what I can tell,
> device_unregister does not put the of_node.
>
>> If you first fix that, you should then be able to call
>> fwnode_handle_put() (instead of of_node_put())
>
> Well, we currently only have a ulpi_of_register, so I don't think we
> will have a fwnode here. But I can use that if you wish.
Hm, looks like I missed the ACPI_COMPANION_SET
So this should probably be fwnode_handle_put.
But ACPI_COMPANION_SET doesn't seem to get the fwnode?
> --Sean
>
>> from
>> ulpi_dev_release(), and that should cover all cases.
>>
>>> root = debugfs_create_dir(dev_name(dev), ULPI_ROOT);
>>> debugfs_create_file("regs", 0444, root, ulpi, &ulpi_regs_ops);
>>> @@ -314,6 +314,10 @@ static int ulpi_register(struct device *dev, struct ulpi *ulpi)
>>> ulpi->id.vendor, ulpi->id.product);
>>>
>>> return 0;
>>> +
>>> +err:
>>> + of_node_put(ulpi->dev.of_node);
>>> + return ret;
>>
>> So no need for that.
>>
>>> }
>>>
>>> /**
>>> @@ -357,8 +361,8 @@ void ulpi_unregister_interface(struct ulpi *ulpi)
>>> {
>>> debugfs_remove_recursive(debugfs_lookup(dev_name(&ulpi->dev),
>>> ULPI_ROOT));
>>> - of_node_put(ulpi->dev.of_node);
>>> device_unregister(&ulpi->dev);
>>> + of_node_put(ulpi->dev.of_node);
>>> }
>>
>> And here you can just remove that of_node_put() call.
>>
>> thanks,
>>
>
next prev parent reply other threads:[~2022-01-25 17:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 17:33 [PATCH v2 1/2] usb: ulpi: Add debugfs support Sean Anderson
2022-01-24 17:33 ` [PATCH v2 2/2] usb: ulpi: Call of_node_put correctly Sean Anderson
2022-01-25 9:18 ` Heikki Krogerus
2022-01-25 16:53 ` Sean Anderson
2022-01-25 17:01 ` Sean Anderson [this message]
2022-01-26 13:04 ` Greg Kroah-Hartman
2022-01-27 16:25 ` Sean Anderson
2022-01-26 13:37 ` Heikki Krogerus
2022-01-26 13:05 ` [PATCH v2 1/2] usb: ulpi: Add debugfs support Greg Kroah-Hartman
2022-01-27 16:31 ` Sean Anderson
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