On 10/30/18 11:46 AM, Thomas Gleixner wrote: > On Tue, 30 Oct 2018, Jens Axboe wrote: >> On 10/30/18 11:25 AM, Thomas Gleixner wrote: >>> Jens, >>> >>> On Tue, 30 Oct 2018, Jens Axboe wrote: >>>> On 10/30/18 10:02 AM, Keith Busch wrote: >>>>> pci_alloc_irq_vectors_affinity() starts at the provided max_vecs. If >>>>> that doesn't work, it will iterate down to min_vecs without returning to >>>>> the caller. The caller doesn't have a chance to adjust its sets between >>>>> iterations when you provide a range. >>>>> >>>>> The 'masks' overrun problem happens if the caller provides min_vecs >>>>> as a smaller value than the sum of the set (plus any reserved). >>>>> >>>>> If it's up to the caller to ensure that doesn't happen, then min and >>>>> max must both be the same value, and that value must also be the same as >>>>> the set sum + reserved vectors. The range just becomes redundant since >>>>> it is already bounded by the set. >>>>> >>>>> Using the nvme example, it would need something like this to prevent the >>>>> 'masks' overrun: >>>> >>>> OK, now I hear what you are saying. And you are right, the callers needs >>>> to provide minvec == maxvec for sets, and then have a loop around that >>>> to adjust as needed. >>> >>> But then we should enforce it in the core code, right? >> >> Yes, I was going to ask you if you want a followup patch for that, or >> an updated version of the original? > > Updated combo patch would be nice :) I'll re-post the series with the updated combo some time later today. > lazytglx I understand :-) -- Jens Axboe
