On Wed, 17 May 2017, 3:28pm, Bjorn Helgaas wrote:
> Your summary is "Only disable affinity settings if pre and post vector
> count is equal to max_vecs and not min_vecs", but the patch doesn't
> mention max_vecs anywhere. There must be a clearer way to word this.
>
Agree. will update the patch summary
> On Mon, Apr 17, 2017 at 06:19:25PM -0700, Himanshu Madhani wrote:
> > 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.
> >
> > Fixes: dfef358bd1be ("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: <stable@xxxxxxxxxxxxxxx> # 4.10
> > ---
> > v4 --> v5
> > o Fixed Zero day kernel build failure.
> >
> > v3 --> v4
> > o Moved pre/post reserved vector range checks to affinity.c as per
> > comments from Bjorn Helgaas.
> >
> > 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()
> >
> >
> > drivers/pci/msi.c | 14 ++------------
> > include/linux/interrupt.h | 4 ++--
> > kernel/irq/affinity.c | 12 +++++++++++-
> > 3 files changed, 15 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> > index d571bc330686..8adf22f41cf9 100644
> > --- a/drivers/pci/msi.c
> > +++ b/drivers/pci/msi.c
> > @@ -1072,7 +1072,7 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
> >
> > for (;;) {
> > if (affd) {
> > - nvec = irq_calc_affinity_vectors(nvec, affd);
> > + nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
> > if (nvec < minvec)
> > return -ENOSPC;
> > }
> > @@ -1111,7 +1111,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
> >
> > for (;;) {
> > if (affd) {
> > - nvec = irq_calc_affinity_vectors(nvec, affd);
> > + nvec = irq_calc_affinity_vectors(minvec, nvec, affd);
> > if (nvec < minvec)
> > return -ENOSPC;
> > }
> > @@ -1179,16 +1179,6 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
> > if (flags & PCI_IRQ_AFFINITY) {
> > if (!affd)
> > affd = &msi_default_affd;
> > -
> > - 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;
> > diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
> > index 53144e78a369..63b246dd8258 100644
> > --- a/include/linux/interrupt.h
> > +++ b/include/linux/interrupt.h
> > @@ -291,7 +291,7 @@ extern int
> > irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
> >
> > struct cpumask *irq_create_affinity_masks(int nvec, const struct irq_affinity *affd);
> > -int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd);
> > +int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd);
> >
> > #else /* CONFIG_SMP */
> >
> > @@ -331,7 +331,7 @@ irq_create_affinity_masks(int nvec, const struct irq_affinity *affd)
> > }
> >
> > static inline int
> > -irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd)
> > +irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd)
> > {
> > return maxvec;
> > }
> > diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
> > index d052947fe785..59645fa66385 100644
> > --- a/kernel/irq/affinity.c
> > +++ b/kernel/irq/affinity.c
> > @@ -69,6 +69,13 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
> > if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
> > return NULL;
> >
> > + /*
> > + * If there aren't any vectors left after applying the pre/post
> > + * vectors don't bother with assigning affinity.
> > + */
> > + if (!affv)
> > + return NULL;
>
> This looks like it might require cleanup, e.g., branching to "out".
>
> But the test of "affv" doesn't depend on the zalloc_cpu_mask_var(), so
> you could just move this test above the call to zalloc_cpu_mask_var(),
> and then you wouldn't need any cleanup.
>
Make sense. Will update patch.
> > +
> > masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
> > if (!masks)
> > goto out;
> > @@ -143,12 +150,15 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
> > * @maxvec: The maximum number of vectors available
> > * @affd: Description of the affinity requirements
> > */
> > -int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd)
> > +int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd)
>
> This function has a kernel-doc comment above it, and you're adding a
> parameter, so please update the kernel-doc to match.
>
Sure. will add kernel-doc
> > {
> > int resv = affd->pre_vectors + affd->post_vectors;
> > int vecs = maxvec - resv;
> > int cpus;
> >
> > + if (resv > minvec)
> > + return 0;
> > +
> > /* Stabilize the cpumasks */
> > get_online_cpus();
> > cpus = cpumask_weight(cpu_online_mask);
> > --
> > 2.12.0
> >
>
Will send revised patch after suggested updates.
Thanks,
Himanshu
