Re: [PATCH 1/2]drivers/usb/core/sysfs.c Fix variable 'retval' setbut not used
From: Greg KH
Date: Tue Aug 03 2010 - 13:22:30 EST
On Tue, Aug 03, 2010 at 01:09:31PM -0400, Alan Stern wrote:
> On Tue, 3 Aug 2010, Greg KH wrote:
> > On Tue, Aug 03, 2010 at 11:34:26AM -0400, Alan Stern wrote:
> > > On Tue, 3 Aug 2010 Valdis.Kletnieks@xxxxxx wrote:
> > >
> > > > > Failure to create a file in sysfs is almost never fatal and usually not
> > > > > even dangerous. Ignoring the error is generally better than failing
> > > > > the entire operation.
> > > >
> > > > Then why the __must_check attribute if it's usually ignorable? I thought
> > > > that was reserved for functions that you damned sight better well check
> > > > for errors because bad things are afoot otherwise?
> > >
> > > That's a good question. Perhaps Greg KH knows the answer.
> > You should check the return value for that function. To not do that is
> > a bug. This one looks like it snuck through. Fixing it properly is the
> > correct thing to do.
> In other words, usb_set_configuration() should fail if
> usb_create_sysfs_intf_files() is unable to create the attribute file
> containing an interface's string descriptor?
> And likewise, ehci_run() should fail if the "companion" and debugging
> files can't be created?
Ah, yeah, now I recall why we didn't do anything with those values :)
It's best to continue on. Perhaps we should just emit a warning to the
system log if the file fails to be created and move on. That would
properly handle the return value and keep gcc, and everyone else, happy.
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