From: Tang Bin <tangbin@cmss.chinamobile.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: stern@rowland.harvard.edu, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org,
Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Subject: Re: [PATCH] USB: host: ehci: Add error handlinginehci_mxc_drv_probe()
Date: Fri, 8 May 2020 23:03:27 +0800 [thread overview]
Message-ID: <107353c0-09f2-858d-2a87-498e2d8584c6@cmss.chinamobile.com> (raw)
In-Reply-To: <20200508143110.GA447591@kroah.com>
On 2020/5/8 22:31, Greg KH wrote:
> On Fri, May 08, 2020 at 09:55:53PM +0800, Tang Bin wrote:
>> Hi, Greg:
>>
>> On 2020/5/8 19:48, Greg KH wrote:
>>> On Fri, May 08, 2020 at 07:44:53PM +0800, Tang Bin wrote:
>>>> The function ehci_mxc_drv_probe() does not perform sufficient error
>>>> checking after executing platform_get_irq(), thus fix it.
>>>>
>>>> Fixes: 7e8d5cd93fa ("USB: Add EHCI support for MX27 and MX31 based boards")
>>>> Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
>>>> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
>>>> ---
>>>> drivers/usb/host/ehci-mxc.c | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/drivers/usb/host/ehci-mxc.c b/drivers/usb/host/ehci-mxc.c
>>>> index a1eb5ee77..a0b42ba59 100644
>>>> --- a/drivers/usb/host/ehci-mxc.c
>>>> +++ b/drivers/usb/host/ehci-mxc.c
>>>> @@ -50,6 +50,8 @@ static int ehci_mxc_drv_probe(struct platform_device *pdev)
>>>> }
>>>> irq = platform_get_irq(pdev, 0);
>>>> + if (irq < 0)
>>>> + return irq;
>>> <= ?
>> In the file 'drivers/base/platform.c', the function platform_get_irq() is
>> explained and used as follows:
>>
>> * Gets an IRQ for a platform device and prints an error message if
>> finding the
>> * IRQ fails. Device drivers should check the return value for errors so
>> as to
>> * not pass a negative integer value to the request_irq() APIs.
>> *
>> * Example:
>> * int irq = platform_get_irq(pdev, 0);
>> * if (irq < 0)
>> * return irq;
>> *
>> * Return: IRQ number on success, negative error number on failure.
>>
>> And in my hardware experiment, even if I set the irq failed deliberately in
>> the DTS, the returned value is negative instead of zero.
> Please read the thread at
> https://lore.kernel.org/r/20200501224042.141366-1-helgaas%40kernel.org
> for more details about this.
>
Great, It looks beautiful, finally someone took a knife to the file
'platform.c'.
I have been studied this place for a long time, and don't know what
platform can return 0, which made me curious.
So the example should be:
* int irq = platform_get_irq(pdev, 0);
* if (irq <= 0)
* return irq;
Thanks,
Tang Bin
next prev parent reply other threads:[~2020-05-08 15:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-08 11:44 [PATCH] USB: host: ehci: Add error handling in ehci_mxc_drv_probe() Tang Bin
2020-05-08 11:48 ` Greg KH
2020-05-08 13:55 ` [PATCH] USB: host: ehci: Add error handling inehci_mxc_drv_probe() Tang Bin
2020-05-08 14:31 ` Greg KH
2020-05-08 15:03 ` Tang Bin [this message]
2020-05-08 20:27 ` [PATCH] USB: host: ehci: Add error handlinginehci_mxc_drv_probe() Sergei Shtylyov
2020-05-09 1:13 ` Tang Bin
2020-05-08 20:30 ` [PATCH] USB: host: ehci: Add error handling in ehci_mxc_drv_probe() Sergei Shtylyov
2020-05-08 13:51 ` Alan Stern
2020-05-13 12:55 ` Tang Bin
2020-05-13 13:01 ` Greg KH
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