On Thu, Mar 30, 2017 at 04:25:54PM -0700, Himanshu Madhani wrote:
>
> 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.
Great, thanks! I just wanted to make sure we weren't each waiting for
the other. I appreciate your willingness to investigate other
options.
Bjorn
