Hi Bjorn,
On Thu, 30 Mar 2017, 4:21pm, Bjorn Helgaas wrote:
> On Thu, Mar 23, 2017 at 12:29:28PM -0500, Bjorn Helgaas wrote:
> > On Wed, Mar 01, 2017 at 03:31:58PM -0800, Himanshu Madhani wrote:
> > > From: Michael Hernandez <michael.hernandez@xxxxxxxxxx>
> > >
> > > min_vecs is the minimum amount of vectors needed to operate in MSI-X mode
> > > which may just include the vectors that don't need affinity.
> > >
> > > Disabling affinity settings causes the qla2xxx driver scsi_add_host
> > > to fail when blk_mq is enabled as the blk_mq_pci_map_queues expects
> > > affinity masks on each vector.
> > >
> > > v2 --> v3
> > > o fixed code as per review comments.
> > >
> > > v1 --> v2
> > >
> > > o Moved the check from pci_alloc_irq_vectors_affinity() to
> > > __pci_enable_{msi|msix}_range()
> > >
> > > Fixes: dfef358 ("PCI/MSI: Don't apply affinity if there aren't enough vectors left")
> > > Signed-off-by: Michael Hernandez <michael.hernandez@xxxxxxxxxx>
> > > Signed-off-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
> > > Cc: Christoph Hellwig <hch@xxxxxx>
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > ---
> > > drivers/pci/msi.c | 25 ++++++++++++++++++-------
> > > 1 files changed, 18 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> > > index 7f73bac..46c0cdd 100644
> > > --- a/drivers/pci/msi.c
> > > +++ b/drivers/pci/msi.c
> > > @@ -1091,6 +1091,15 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
> > >
> > > for (;;) {
> > > if (affd) {
> > > + /*
> > > + * If there aren't any vectors left after applying the
> > > + * pre/post vectors don't bother with assigning
> > > + * affinity.
> > > + */
> > > + if (affd->pre_vectors + affd->post_vectors == nvec)
> > > + affd = NULL;
> > > + }
> >
> > I don't really like this because affd->pre_vectors and
> > affd->post_vectors are not PCI MSI concepts. I think they really
> > belong in irq/affinity.c, e.g., maybe this could be checked in
> > irq_create_affinity_masks().
> >
> > If that could be done, we wouldn't have to duplicate the checks here
> > for both MSI and MSI-X.
> >
> > I raised a similar question earlier:
> > http://lkml.kernel.org/r/20170202173659.GD21267@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> I want to make progress on this, but that means a little conversation
> here. Maybe we want to merge this patch as-is, but I'd like to hear
> the reasons why it wouldn't really work to move the checks to
> irq/affinity.c.
>
> For now I'll mark it as "changes requested" in patchwork, which means
> it will fall off my to-do list until it's reposted.
>
Sorry for going silent on this patch. We've been working internally to
update patch as per your suggestion. I am planning to repost new patch
once we have completed our testing. I should be able to post updated
patch sometimes next week for your review.
> > > + if (affd) {
> > > nvec = irq_calc_affinity_vectors(nvec, affd);
> > > if (nvec < minvec)
> > > return -ENOSPC;
> > > @@ -1138,6 +1147,15 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
> > >
> > > for (;;) {
> > > if (affd) {
> > > + /*
> > > + * If there aren't any vectors left after applying the
> > > + * pre/post vectors don't bother with assigning
> > > + * affinity.
> > > + */
> > > + if (affd->pre_vectors + affd->post_vectors == nvec)
> > > + affd = NULL;
> > > + }
> > > + if (affd) {
> > > nvec = irq_calc_affinity_vectors(nvec, affd);
> > > if (nvec < minvec)
> > > return -ENOSPC;
> > > @@ -1209,13 +1227,6 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
> > >
> > > if (affd->pre_vectors + affd->post_vectors > min_vecs)
> > > return -EINVAL;
> > > -
> > > - /*
> > > - * If there aren't any vectors left after applying the pre/post
> > > - * vectors don't bother with assigning affinity.
> > > - */
> > > - if (affd->pre_vectors + affd->post_vectors == min_vecs)
> > > - affd = NULL;
> > > } else {
> > > if (WARN_ON(affd))
> > > affd = NULL;
> > > --
> > > 1.7.1
> > >
>
Thanks,
- Himanshu
