Messages in this thread | | | Date | Tue, 31 Jan 2012 06:53:32 -0800 | From | Greg KH <> | Subject | Re: [PATCH] usb: dwc3: debugfs: fix error check |
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On Tue, Jan 31, 2012 at 02:03:51PM +0200, Felipe Balbi wrote: > debugfs APIs will return two different error > values depending on the situation: > > -> if debugfs isn't enabled in the kernel: > it will return -ENODEV > > -> if debugfs is enabled in the kernel: > it will return NULL > > This means that blindly using IS_ERR() isn't > enough and, in fact, will not work on a real > error condition. > > While we could be checking for a NULL pointer > only because we only compile and link debugfs.o > when CONFIG_DEBUG_FS is enabled, we decided > to play it safe should any of the debugfs rules > change over time.
The rules should not change over time, and if they do, any in-kernel users will be fixed up.
This shouldn't be that hard, just check for NULL and move on if an error happens, don't mess with the IS_ERR() stuff at all.
Look at how the USB core handles this, and use that logic.
thanks,
greg k-h
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