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? Thanks, tglx
