Messages in this thread |  | | | Subject | Re: [RFC PATCH] convert uhci-hcd to use debugfs | | From | Josh Boyer <> | | Date | Fri, 10 Dec 2004 10:21:50 -0600 |
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On Fri, 2004-12-10 at 09:27, Greg KH wrote: > > > > -#ifdef CONFIG_PROC_FS > > > - ent = create_proc_entry(hcd->self.bus_name, S_IFREG|S_IRUGO|S_IWUSR, uhci_proc_root); > > > - if (!ent) { > > > - dev_err(uhci_dev(uhci), "couldn't create uhci proc entry\n"); > > > + dentry = debugfs_create_file(hcd->self.bus_name, S_IFREG|S_IRUGO|S_IWUSR, uhci_debugfs_root, uhci, &uhci_proc_operations); > > > + if (!dentry) { > > > > That won't work if debugfs is not configured. You'll get back (void *) > > -ENODEV, which is not NULL. > > That's exactly correct. We do _not_ want NULL to be returned if debugfs > is not configured in. We want to be able to detect if an error > happened, not if the feature was just not configured. Otherwise, if we > did return NULL if debugfs was not enabled, this code would just fail > and the uhci startup would never happen. > > This is why people have to wrap proc functions in #ifdef, and why no one > ever checks the return values from devfs calls. It's a real problem and > I don't want to duplicate that again.
Ah, ok I see now. Good point. I should have looked at the code instead of just trying to infer everything from the patch ;).
josh
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