On Wed, May 28, 2025 at 07:52:35PM +0100, Simon Horman wrote:
> On Tue, May 27, 2025 at 08:59:03AM -0700, Shradha Gupta wrote:
> > Currently, the MANA driver allocates MSI-X vectors statically based on
> > MANA_MAX_NUM_QUEUES and num_online_cpus() values and in some cases ends
> > up allocating more vectors than it needs. This is because, by this time
> > we do not have a HW channel and do not know how many IRQs should be
> > allocated.
> >
> > To avoid this, we allocate 1 MSI-X vector during the creation of HWC and
> > after getting the value supported by hardware, dynamically add the
> > remaining MSI-X vectors.
> >
> > Signed-off-by: Shradha Gupta <shradhagu...@linux.microsoft.com>
> > Reviewed-by: Haiyang Zhang <haiya...@microsoft.com>
>
> ...
>
> > +static int mana_gd_setup_irqs(struct pci_dev *pdev, int nvec)
> > +{
> > + struct gdma_context *gc = pci_get_drvdata(pdev);
> > + struct gdma_irq_context *gic;
> > + int *irqs, *start_irqs, irq;
> > + unsigned int cpu;
> > + int err, i;
> > +
> > + cpus_read_lock();
> > +
> > + irqs = kmalloc_array(nvec, sizeof(int), GFP_KERNEL);
> > + if (!irqs) {
> > err = -ENOMEM;
> > - goto free_irq_array;
> > + goto free_irq_vector;
> > }
> >
> > for (i = 0; i < nvec; i++) {
> > - gic = &gc->irq_contexts[i];
> > + gic = kzalloc(sizeof(*gic), GFP_KERNEL);
> > + if (!gic) {
> > + err = -ENOMEM;
> > + goto free_irq;
> > + }
> > +
> > gic->handler = mana_gd_process_eq_events;
> > INIT_LIST_HEAD(&gic->eq_list);
> > spin_lock_init(&gic->lock);
> > @@ -1418,69 +1498,128 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev)
> > snprintf(gic->name, MANA_IRQ_NAME_SZ, "mana_q%d@pci:%s",
> > i - 1, pci_name(pdev));
> >
> > - irq = pci_irq_vector(pdev, i);
> > - if (irq < 0) {
> > - err = irq;
> > - goto free_irq;
> > + irqs[i] = pci_irq_vector(pdev, i);
> > + if (irqs[i] < 0) {
> > + err = irqs[i];
> > + goto free_current_gic;
> > }
> >
> > - if (!i) {
> > - err = request_irq(irq, mana_gd_intr, 0, gic->name, gic);
> > - if (err)
> > - goto free_irq;
> > -
> > - /* If number of IRQ is one extra than number of online
> > CPUs,
> > - * then we need to assign IRQ0 (hwc irq) and IRQ1 to
> > - * same CPU.
> > - * Else we will use different CPUs for IRQ0 and IRQ1.
> > - * Also we are using cpumask_local_spread instead of
> > - * cpumask_first for the node, because the node can be
> > - * mem only.
> > - */
> > - if (start_irq_index) {
> > - cpu = cpumask_local_spread(i, gc->numa_node);
> > - irq_set_affinity_and_hint(irq, cpumask_of(cpu));
> > - } else {
> > - irqs[start_irq_index] = irq;
> > - }
> > - } else {
> > - irqs[i - start_irq_index] = irq;
> > - err = request_irq(irqs[i - start_irq_index],
> > mana_gd_intr, 0,
> > - gic->name, gic);
> > - if (err)
> > - goto free_irq;
> > - }
> > + err = request_irq(irqs[i], mana_gd_intr, 0, gic->name, gic);
> > + if (err)
> > + goto free_current_gic;
>
> Jumping to free_current_gic will free start_irqs.
> However, start_irqs isn't initialised until a few lines below.
>
> Flagged by Smatch.
>
Thanks Simon, I'll get this in next version
> > +
> > + xa_store(&gc->irq_contexts, i, gic, GFP_KERNEL);
> > }
> >
> > - err = irq_setup(irqs, nvec - start_irq_index, gc->numa_node, false);
> > + /* If number of IRQ is one extra than number of online CPUs,
> > + * then we need to assign IRQ0 (hwc irq) and IRQ1 to
> > + * same CPU.
> > + * Else we will use different CPUs for IRQ0 and IRQ1.
> > + * Also we are using cpumask_local_spread instead of
> > + * cpumask_first for the node, because the node can be
> > + * mem only.
> > + */
> > + start_irqs = irqs;
> > + if (nvec > num_online_cpus()) {
> > + cpu = cpumask_local_spread(0, gc->numa_node);
> > + irq_set_affinity_and_hint(irqs[0], cpumask_of(cpu));
> > + irqs++;
> > + nvec -= 1;
> > + }
> > +
> > + err = irq_setup(irqs, nvec, gc->numa_node, false);
> > if (err)
> > goto free_irq;
> >
> > - gc->max_num_msix = nvec;
> > - gc->num_msix_usable = nvec;
> > cpus_read_unlock();
> > - kfree(irqs);
> > + kfree(start_irqs);
> > return 0;
> >
> > +free_current_gic:
> > + kfree(gic);
> > free_irq:
> > - for (j = i - 1; j >= 0; j--) {
> > - irq = pci_irq_vector(pdev, j);
> > - gic = &gc->irq_contexts[j];
> > + for (i -= 1; i >= 0; i--) {
> > + irq = pci_irq_vector(pdev, i);
> > + gic = xa_load(&gc->irq_contexts, i);
> > + if (WARN_ON(!gic))
> > + continue;
> >
> > irq_update_affinity_hint(irq, NULL);
> > free_irq(irq, gic);
> > + xa_erase(&gc->irq_contexts, i);
> > + kfree(gic);
> > }
> >
> > - kfree(gc->irq_contexts);
> > - gc->irq_contexts = NULL;
> > -free_irq_array:
> > - kfree(irqs);
> > + kfree(start_irqs);
> > free_irq_vector:
> > cpus_read_unlock();
> > - pci_free_irq_vectors(pdev);
> > return err;
> > }
>
> ...
