Messages in this thread | | | Date | Sun, 4 Jan 2009 12:41:49 -0800 (PST) | From | Trent Piepho <> | Subject | Re: [PATCH] printk: Let %pR handle NULL pointers |
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On Sun, 4 Jan 2009, Benjamin Herrenschmidt wrote: > > I thought of doing that too, but then all the various %pX formats would all > > have to print the same for NULL pointers. For instance a resource prints > > out like "[0x1000-0x100f]", so I chose "[NULL]" for printing a null > > resource pointer. Maybe "[]" or "[-]" would be better? A null MAC address > > could be ":::::" or "x:x:x:x:x:x". "N.U.L.L" or "x.x.x.x" for a null IP4 > > address. And so on. So the printout looks nicer when a NULL pointer isn't > > a bug. > > And how often is that ?
For resource pointers it's not uncommon. There are many cases when it's perfectly ok for a resource pointer to be null, e.g. res->parent is often null, pci devices and busses don't usually have all possible ranges, etc. It nice to get decent info printouts without having the check for NULL pointers.
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