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Merge branch 'pci/host-vmd' into next
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* pci/host-vmd:
  PCI: vmd: Fix suspend handlers defined-but-not-used warning
  PCI: vmd: Use SRCU as a local RCU to prevent delaying global RCU
  PCI: vmd: Remove unnecessary pci_set_drvdata()
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Bjorn Helgaas committed Dec 12, 2016
2 parents d34efd2 + 42db500 commit b08d2e6
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Showing 2 changed files with 23 additions and 9 deletions.
2 changes: 1 addition & 1 deletion drivers/pci/host/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -288,7 +288,7 @@ config PCIE_ROCKCHIP
4 slots.

config VMD
depends on PCI_MSI && X86_64
depends on PCI_MSI && X86_64 && SRCU
tristate "Intel Volume Management Device Driver"
default N
---help---
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30 changes: 22 additions & 8 deletions drivers/pci/host/vmd.c
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/pci.h>
#include <linux/srcu.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>

Expand All @@ -39,7 +40,6 @@ static DEFINE_RAW_SPINLOCK(list_lock);
/**
* struct vmd_irq - private data to map driver IRQ to the VMD shared vector
* @node: list item for parent traversal.
* @rcu: RCU callback item for freeing.
* @irq: back pointer to parent.
* @enabled: true if driver enabled IRQ
* @virq: the virtual IRQ value provided to the requesting driver.
Expand All @@ -49,7 +49,6 @@ static DEFINE_RAW_SPINLOCK(list_lock);
*/
struct vmd_irq {
struct list_head node;
struct rcu_head rcu;
struct vmd_irq_list *irq;
bool enabled;
unsigned int virq;
Expand All @@ -58,11 +57,13 @@ struct vmd_irq {
/**
* struct vmd_irq_list - list of driver requested IRQs mapping to a VMD vector
* @irq_list: the list of irq's the VMD one demuxes to.
* @srcu: SRCU struct for local synchronization.
* @count: number of child IRQs assigned to this vector; used to track
* sharing.
*/
struct vmd_irq_list {
struct list_head irq_list;
struct srcu_struct srcu;
unsigned int count;
};

Expand Down Expand Up @@ -224,14 +225,14 @@ static void vmd_msi_free(struct irq_domain *domain,
struct vmd_irq *vmdirq = irq_get_chip_data(virq);
unsigned long flags;

synchronize_rcu();
synchronize_srcu(&vmdirq->irq->srcu);

/* XXX: Potential optimization to rebalance */
raw_spin_lock_irqsave(&list_lock, flags);
vmdirq->irq->count--;
raw_spin_unlock_irqrestore(&list_lock, flags);

kfree_rcu(vmdirq, rcu);
kfree(vmdirq);
}

static int vmd_msi_prepare(struct irq_domain *domain, struct device *dev,
Expand Down Expand Up @@ -646,11 +647,12 @@ static irqreturn_t vmd_irq(int irq, void *data)
{
struct vmd_irq_list *irqs = data;
struct vmd_irq *vmdirq;
int idx;

rcu_read_lock();
idx = srcu_read_lock(&irqs->srcu);
list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node)
generic_handle_irq(vmdirq->virq);
rcu_read_unlock();
srcu_read_unlock(&irqs->srcu, idx);

return IRQ_HANDLED;
}
Expand Down Expand Up @@ -696,6 +698,10 @@ 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);
if (err)
return err;

INIT_LIST_HEAD(&vmd->irqs[i].irq_list);
err = devm_request_irq(&dev->dev, pci_irq_vector(dev, i),
vmd_irq, 0, "vmd", &vmd->irqs[i]);
Expand All @@ -714,20 +720,28 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
return 0;
}

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);
}

static void vmd_remove(struct pci_dev *dev)
{
struct vmd_dev *vmd = pci_get_drvdata(dev);

vmd_detach_resources(vmd);
pci_set_drvdata(dev, NULL);
vmd_cleanup_srcu(vmd);
sysfs_remove_link(&vmd->dev->dev.kobj, "domain");
pci_stop_root_bus(vmd->bus);
pci_remove_root_bus(vmd->bus);
vmd_teardown_dma_ops(vmd);
irq_domain_remove(vmd->irq_domain);
}

#ifdef CONFIG_PM
#ifdef CONFIG_PM_SLEEP
static int vmd_suspend(struct device *dev)
{
struct pci_dev *pdev = to_pci_dev(dev);
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