Messages in this thread | | | Date | Mon, 4 Feb 2013 08:37:16 -0800 | From | Tejun Heo <> | Subject | Re: [PATCH 60/62] sctp: convert to idr_alloc() |
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On Mon, Feb 04, 2013 at 11:22:26AM -0500, Vlad Yasevich wrote: > >+ ret = idr_alloc(&sctp_assocs_id, asoc, idr_low, 0, GFP_NOWAIT); > >+ if (ret >= 0) { > > In SCTP, association id is not allowed to be 0, so we have to treat > 0 as an error.
That condition is specified via @idr_low and 0 won't be returned. If your point is that the condition better be "ret > 0" for clarity, I don't know. At that point, we already requested an ID in the acceptable range and testing whether the allocation succeeded or not where failure will always be indicated by -errno.
We can surely add "if (ret == 0) ret = -EINVAL" but that would be a completely dead path (should we add dead retry loop too?). If we don't add such code, the code would appear as silently ignoring error.
So, I think "ret >= 0" is better there. Maybe we can throw in a comment explaining idr_low never goes to zero.
BTW, this style of cyclic allocation is broken. It's prone to -ENOSPC failure after the first wrap around. I think we need to implement proper cyclic support in idr, but let's worry about that later.
Thanks.
-- tejun
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