Hello Thomas and Guys, On Mon, Aug 5, 2019 at 9:19 AM Ming Lei <[email protected]> wrote: > > Since commit c66d4bd110a1f8 ("genirq/affinity: Add new callback for > (re)calculating interrupt sets"), irq_create_affinity_masks() returns > NULL in case of single vector. This change has caused regression on some > drivers, such as lpfc. > > The problem is that single vector may be triggered in some generic cases: > 1) kdump kernel 2) irq vectors resource is close to exhaustion. > > If we don't create affinity mask for single vector, almost every caller > has to handle the special case. > > So still create affinity mask for single vector, since > irq_create_affinity_masks() > is capable of handling that. > > Cc: Marc Zyngier <[email protected]> > Cc: Christoph Hellwig <[email protected]> > Cc: Bjorn Helgaas <[email protected]> > Cc: Jens Axboe <[email protected]> > Cc: [email protected] > Cc: Sagi Grimberg <[email protected]> > Cc: [email protected] > Cc: [email protected] > Cc: Keith Busch <[email protected]> > Cc: Sumit Saxena <[email protected]> > Cc: Kashyap Desai <[email protected]> > Cc: Shivasharan Srikanteshwara <[email protected]> > Fixes: c66d4bd110a1f8 ("genirq/affinity: Add new callback for (re)calculating > interrupt sets") > Signed-off-by: Ming Lei <[email protected]> > --- > kernel/irq/affinity.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c > index 4352b08ae48d..6fef48033f96 100644 > --- a/kernel/irq/affinity.c > +++ b/kernel/irq/affinity.c > @@ -251,11 +251,9 @@ irq_create_affinity_masks(unsigned int nvecs, struct > irq_affinity *affd) > * Determine the number of vectors which need interrupt affinities > * assigned. If the pre/post request exhausts the available vectors > * then nothing to do here except for invoking the calc_sets() > - * callback so the device driver can adjust to the situation. If there > - * is only a single vector, then managing the queue is pointless as > - * well. > + * callback so the device driver can adjust to the situation. > */ > - if (nvecs > 1 && nvecs > affd->pre_vectors + affd->post_vectors) > + if (nvecs > affd->pre_vectors + affd->post_vectors) > affvecs = nvecs - affd->pre_vectors - affd->post_vectors; > else > affvecs = 0;
Without this patch, kdump kernel may not work, so could you take a look at this patch? Thanks, Ming Lei
