On Mon, Oct 21, 2019 at 05:47:39AM -0600, Jon Derrick wrote:
> With CONFIG_MAXSMP and other debugging options enabled, the size of an
> srcu_struct can grow quite large. These are embedded in the vmd_irq_list
> struct, and a N=64 allocation can exceed MAX_ORDER, violating reclaim
> rules.
>
> This patch changes the irq list array into an array of pointers to irq
> lists to avoid allocation failures with greater msix counts.
>
> Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
> ---
> drivers/pci/controller/vmd.c | 33 ++++++++++++++++++++-------------
> 1 file changed, 20 insertions(+), 13 deletions(-)
Hi Jon,
I think that for bisectability reasons these two patches should
be squashed together. Also if you can provide more fine grain details
of what we are fixing in the commit log I think that would be
beneficial.
Thanks,
Lorenzo
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index c4de95a..096006e 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -92,7 +92,7 @@ struct vmd_dev {
> char __iomem *cfgbar;
>
> int msix_count;
> - struct vmd_irq_list *irqs;
> + struct vmd_irq_list **irqs;
>
> struct pci_sysdata sysdata;
> struct resource resources[3];
> @@ -194,7 +194,7 @@ static struct vmd_irq_list *vmd_next_irq(struct vmd_dev *vmd, struct msi_desc *d
> unsigned long flags;
>
> if (vmd->msix_count == 1)
> - return &vmd->irqs[0];
> + return vmd->irqs[0];
>
> /*
> * White list for fast-interrupt handlers. All others will share the
> @@ -204,17 +204,17 @@ static struct vmd_irq_list *vmd_next_irq(struct vmd_dev *vmd, struct msi_desc *d
> case PCI_CLASS_STORAGE_EXPRESS:
> break;
> default:
> - return &vmd->irqs[0];
> + return vmd->irqs[0];
> }
>
> raw_spin_lock_irqsave(&list_lock, flags);
> for (i = 1; i < vmd->msix_count; i++)
> - if (vmd->irqs[i].count < vmd->irqs[best].count)
> + if (vmd->irqs[i]->count < vmd->irqs[best]->count)
> best = i;
> - vmd->irqs[best].count++;
> + vmd->irqs[best]->count++;
> raw_spin_unlock_irqrestore(&list_lock, flags);
>
> - return &vmd->irqs[best];
> + return vmd->irqs[best];
> }
>
> static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
> @@ -764,15 +764,22 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
> return -ENOMEM;
>
> for (i = 0; i < vmd->msix_count; i++) {
> - err = init_srcu_struct(&vmd->irqs[i].srcu);
> + vmd->irqs[i] = devm_kcalloc(&dev->dev, 1, sizeof(**vmd->irqs),
> + GFP_KERNEL);
> + if (!vmd->irqs[i])
> + return -ENOMEM;
> + }
> +
> + for (i = 0; i < vmd->msix_count; i++) {
> + err = init_srcu_struct(&vmd->irqs[i]->srcu);
> if (err)
> return err;
>
> - INIT_LIST_HEAD(&vmd->irqs[i].irq_list);
> - vmd->irqs[i].index = i;
> + INIT_LIST_HEAD(&vmd->irqs[i]->irq_list);
> + vmd->irqs[i]->index = i;
> err = devm_request_irq(&dev->dev, pci_irq_vector(dev, i),
> vmd_irq, IRQF_NO_THREAD,
> - "vmd", &vmd->irqs[i]);
> + "vmd", vmd->irqs[i]);
> if (err)
> return err;
> }
> @@ -793,7 +800,7 @@ static void vmd_cleanup_srcu(struct vmd_dev *vmd)
> int i;
>
> for (i = 0; i < vmd->msix_count; i++)
> - cleanup_srcu_struct(&vmd->irqs[i].srcu);
> + cleanup_srcu_struct(&vmd->irqs[i]->srcu);
> }
>
> static void vmd_remove(struct pci_dev *dev)
> @@ -817,7 +824,7 @@ static int vmd_suspend(struct device *dev)
> int i;
>
> for (i = 0; i < vmd->msix_count; i++)
> - devm_free_irq(dev, pci_irq_vector(pdev, i), &vmd->irqs[i]);
> + devm_free_irq(dev, pci_irq_vector(pdev, i), vmd->irqs[i]);
>
> pci_save_state(pdev);
> return 0;
> @@ -832,7 +839,7 @@ static int vmd_resume(struct device *dev)
> for (i = 0; i < vmd->msix_count; i++) {
> err = devm_request_irq(dev, pci_irq_vector(pdev, i),
> vmd_irq, IRQF_NO_THREAD,
> - "vmd", &vmd->irqs[i]);
> + "vmd", vmd->irqs[i]);
> if (err)
> return err;
> }
> --
> 1.8.3.1
>
