Messages in this thread | | | Subject | Re: [PATCH] USB: host: ehci: Add error handlinginehci_mxc_drv_probe() | From | Tang Bin <> | Date | Fri, 8 May 2020 23:03:27 +0800 |
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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
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