Re: [PATCH v3 2/2] PCI: hv: Refactor hv_irq_unmask() to use cpumask_to_vpset()
From: Lorenzo Pieralisi
Date: Wed Feb 27 2019 - 09:28:31 EST
On Wed, Feb 27, 2019 at 01:34:44PM +0100, Vitaly Kuznetsov wrote:
> Maya Nakamura <m.maya.nakamura@xxxxxxxxx> writes:
>
> > Remove the duplicate implementation of cpumask_to_vpset() and use the
> > shared implementation. Export hv_max_vp_index, which is required by
> > cpumask_to_vpset().
> >
> > Apply changes to hv_irq_unmask() based on feedback.
> >
>
> I just noticed an issue with this patch, sorry I've missed it before. I
> don't see the commit in Linus' tree, not sure if we should amend this
> one or a follow-up patch is needed.
I will drop this patch from the PCI queue, it does not make sense
to merge a patch adding a bug and fix it up later with a subsequent
one given that it is not upstream yet.
Lorenzo
> > Signed-off-by: Maya Nakamura <m.maya.nakamura@xxxxxxxxx>
> > ---
> > Changes in v3:
> > - Modify to catch all failures from cpumask_to_vpset().
> > - Correct the v2 change log about the commit message.
> >
> > Changes in v2:
> > - Remove unnecessary nr_bank initialization.
> > - Delete two unnecessary dev_err()'s.
> > - Unlock before returning.
> > - Update the commit message.
> >
> > arch/x86/hyperv/hv_init.c | 1 +
> > drivers/pci/controller/pci-hyperv.c | 38 +++++++++++++----------------
> > 2 files changed, 18 insertions(+), 21 deletions(-)
> >
> > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> > index 7abb09e2eeb8..7f2eed1fc81b 100644
> > --- a/arch/x86/hyperv/hv_init.c
> > +++ b/arch/x86/hyperv/hv_init.c
> > @@ -96,6 +96,7 @@ void __percpu **hyperv_pcpu_input_arg;
> > EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
> >
> > u32 hv_max_vp_index;
> > +EXPORT_SYMBOL_GPL(hv_max_vp_index);
> >
> > static int hv_cpu_init(unsigned int cpu)
> > {
> > diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> > index da8b58d8630d..a78def332bbc 100644
> > --- a/drivers/pci/controller/pci-hyperv.c
> > +++ b/drivers/pci/controller/pci-hyperv.c
> > @@ -391,8 +391,6 @@ struct hv_interrupt_entry {
> > u32 data;
> > };
> >
> > -#define HV_VP_SET_BANK_COUNT_MAX 5 /* current implementation limit */
> > -
> > /*
> > * flags for hv_device_interrupt_target.flags
> > */
> > @@ -908,12 +906,12 @@ static void hv_irq_unmask(struct irq_data *data)
> > struct retarget_msi_interrupt *params;
> > struct hv_pcibus_device *hbus;
> > struct cpumask *dest;
> > + cpumask_var_t tmp;
> > struct pci_bus *pbus;
> > struct pci_dev *pdev;
> > unsigned long flags;
> > u32 var_size = 0;
> > - int cpu_vmbus;
> > - int cpu;
> > + int cpu, nr_bank;
> > u64 res;
> >
> > dest = irq_data_get_effective_affinity_mask(data);
> > @@ -953,29 +951,27 @@ static void hv_irq_unmask(struct irq_data *data)
> > */
> > params->int_target.flags |=
> > HV_DEVICE_INTERRUPT_TARGET_PROCESSOR_SET;
> > - params->int_target.vp_set.valid_bank_mask =
> > - (1ull << HV_VP_SET_BANK_COUNT_MAX) - 1;
> > +
> > + if (!alloc_cpumask_var(&tmp, GFP_KERNEL)) {
>
> We can't use GFP_KERNEL here: this is happening under
> hbus->retarget_msi_interrupt_lock spinlock, we should use GFP_ATOMIC
> instead. It may, however, make sense to add the cpumask to a
> pre-allocated structure (e.g. struct hv_pcibus_device) to make sure the
> allocation never fails.
>
> > + res = 1;
> > + goto exit_unlock;
> > + }
> > +
> > + cpumask_and(tmp, dest, cpu_online_mask);
> > + nr_bank = cpumask_to_vpset(¶ms->int_target.vp_set, tmp);
> > + free_cpumask_var(tmp);
> > +
> > + if (nr_bank <= 0) {
> > + res = 1;
> > + goto exit_unlock;
> > + }
> >
> > /*
> > * var-sized hypercall, var-size starts after vp_mask (thus
> > * vp_set.format does not count, but vp_set.valid_bank_mask
> > * does).
> > */
> > - var_size = 1 + HV_VP_SET_BANK_COUNT_MAX;
> > -
> > - for_each_cpu_and(cpu, dest, cpu_online_mask) {
> > - cpu_vmbus = hv_cpu_number_to_vp_number(cpu);
> > -
> > - if (cpu_vmbus >= HV_VP_SET_BANK_COUNT_MAX * 64) {
> > - dev_err(&hbus->hdev->device,
> > - "too high CPU %d", cpu_vmbus);
> > - res = 1;
> > - goto exit_unlock;
> > - }
> > -
> > - params->int_target.vp_set.bank_contents[cpu_vmbus / 64] |=
> > - (1ULL << (cpu_vmbus & 63));
> > - }
> > + var_size = 1 + nr_bank;
> > } else {
> > for_each_cpu_and(cpu, dest, cpu_online_mask) {
> > params->int_target.vp_mask |=
>
> --
> Vitaly