On Fri, 2007-06-01 at 11:58 -0700, Jeremy Fitzhardinge wrote: > Christoph Lameter wrote: > > Hmmm... We got there because SLUB initially return NULL for kmalloc(0). > > Rationale: The user did not request any memory so we wont give him > > any. > > > > That (to my surprise) caused some strange behavior of code and so we then > > decided to keep SLAB behavior and return the smallest available object > > size and put a warning in there. At some later point we plan to switch > > to returning NULL for kmalloc(0). > > > > Unfortunately, returning NULL is indistinguishable from ENOMEM, so the > caller would have to check to see how much it asked for before deciding > to really fail, which doesn't help things much. > > Or does it (should it) return ERRPTR(-ENOMEM)? Bit of a major API > change if not.
I'm on Christoph's side here. I don't think it makes sense for any code to ask to allocate zero bytes of memory and expect valid memory to be returned. Would a compromise be to return a pointer to some known invalid region? This way the kmalloc(0) call would appear successful to the caller, but any access to the memory would result in an exception. Just my 2 cents, Shaggy -- David Kleikamp IBM Linux Technology Center - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
