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genirq/msi: Switch to new irq spreading infrastructure
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Switch MSI over to the new spreading code. If a pci device contains a valid
pointer to a cpumask, then this mask is used for spreading otherwise the
online cpu mask is used. This allows a driver to restrict the spread to a
subset of CPUs, e.g. cpus on a particular node.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: axboe@fb.com
Cc: keith.busch@intel.com
Cc: agordeev@redhat.com
Cc: linux-block@vger.kernel.org
Link: http://lkml.kernel.org/r/1473862739-15032-4-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Thomas Gleixner committed Sep 14, 2016
1 parent 34c3d98 commit e75eafb
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Showing 2 changed files with 87 additions and 72 deletions.
128 changes: 72 additions & 56 deletions drivers/pci/msi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -549,15 +549,23 @@ static int populate_msi_sysfs(struct pci_dev *pdev)
return ret;
}

static struct msi_desc *msi_setup_entry(struct pci_dev *dev, int nvec)
static struct msi_desc *
msi_setup_entry(struct pci_dev *dev, int nvec, bool affinity)
{
u16 control;
struct cpumask *masks = NULL;
struct msi_desc *entry;
u16 control;

if (affinity) {
masks = irq_create_affinity_masks(dev->irq_affinity, nvec);
if (!masks)
pr_err("Unable to allocate affinity masks, ignoring\n");
}

/* MSI Entry Initialization */
entry = alloc_msi_entry(&dev->dev, nvec, NULL);
entry = alloc_msi_entry(&dev->dev, nvec, masks);
if (!entry)
return NULL;
goto out;

pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);

Expand All @@ -568,7 +576,6 @@ static struct msi_desc *msi_setup_entry(struct pci_dev *dev, int nvec)
entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */
entry->msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
entry->msi_attrib.multiple = ilog2(__roundup_pow_of_two(nvec));
entry->affinity = dev->irq_affinity;

if (control & PCI_MSI_FLAGS_64BIT)
entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
Expand All @@ -579,6 +586,8 @@ static struct msi_desc *msi_setup_entry(struct pci_dev *dev, int nvec)
if (entry->msi_attrib.maskbit)
pci_read_config_dword(dev, entry->mask_pos, &entry->masked);

out:
kfree(masks);
return entry;
}

Expand Down Expand Up @@ -607,15 +616,15 @@ static int msi_verify_entries(struct pci_dev *dev)
* an error, and a positive return value indicates the number of interrupts
* which could have been allocated.
*/
static int msi_capability_init(struct pci_dev *dev, int nvec)
static int msi_capability_init(struct pci_dev *dev, int nvec, bool affinity)
{
struct msi_desc *entry;
int ret;
unsigned mask;

pci_msi_set_enable(dev, 0); /* Disable MSI during set up */

entry = msi_setup_entry(dev, nvec);
entry = msi_setup_entry(dev, nvec, affinity);
if (!entry)
return -ENOMEM;

Expand Down Expand Up @@ -678,28 +687,29 @@ static void __iomem *msix_map_region(struct pci_dev *dev, unsigned nr_entries)
}

static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
struct msix_entry *entries, int nvec)
struct msix_entry *entries, int nvec,
bool affinity)
{
const struct cpumask *mask = NULL;
struct cpumask *curmsk, *masks = NULL;
struct msi_desc *entry;
int cpu = -1, i;

for (i = 0; i < nvec; i++) {
if (dev->irq_affinity) {
cpu = cpumask_next(cpu, dev->irq_affinity);
if (cpu >= nr_cpu_ids)
cpu = cpumask_first(dev->irq_affinity);
mask = cpumask_of(cpu);
}
int ret, i;

entry = alloc_msi_entry(&dev->dev, 1, NULL);
if (affinity) {
masks = irq_create_affinity_masks(dev->irq_affinity, nvec);
if (!masks)
pr_err("Unable to allocate affinity masks, ignoring\n");
}

for (i = 0, curmsk = masks; i < nvec; i++) {
entry = alloc_msi_entry(&dev->dev, 1, curmsk);
if (!entry) {
if (!i)
iounmap(base);
else
free_msi_irqs(dev);
/* No enough memory. Don't try again */
return -ENOMEM;
ret = -ENOMEM;
goto out;
}

entry->msi_attrib.is_msix = 1;
Expand All @@ -710,11 +720,14 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
entry->msi_attrib.entry_nr = i;
entry->msi_attrib.default_irq = dev->irq;
entry->mask_base = base;
entry->affinity = mask;

list_add_tail(&entry->list, dev_to_msi_list(&dev->dev));
if (masks)
curmsk++;
}

ret = 0;
out:
kfree(masks);
return 0;
}

Expand Down Expand Up @@ -743,8 +756,8 @@ static void msix_program_entries(struct pci_dev *dev,
* single MSI-X irq. A return of zero indicates the successful setup of
* requested MSI-X entries with allocated irqs or non-zero for otherwise.
**/
static int msix_capability_init(struct pci_dev *dev,
struct msix_entry *entries, int nvec)
static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
int nvec, bool affinity)
{
int ret;
u16 control;
Expand All @@ -759,7 +772,7 @@ static int msix_capability_init(struct pci_dev *dev,
if (!base)
return -ENOMEM;

ret = msix_setup_entries(dev, base, entries, nvec);
ret = msix_setup_entries(dev, base, entries, nvec, affinity);
if (ret)
return ret;

Expand Down Expand Up @@ -939,22 +952,8 @@ int pci_msix_vec_count(struct pci_dev *dev)
}
EXPORT_SYMBOL(pci_msix_vec_count);

/**
* pci_enable_msix - configure device's MSI-X capability structure
* @dev: pointer to the pci_dev data structure of MSI-X device function
* @entries: pointer to an array of MSI-X entries (optional)
* @nvec: number of MSI-X irqs requested for allocation by device driver
*
* Setup the MSI-X capability structure of device function with the number
* of requested irqs upon its software driver call to request for
* MSI-X mode enabled on its hardware device function. A return of zero
* indicates the successful configuration of MSI-X capability structure
* with new allocated MSI-X irqs. A return of < 0 indicates a failure.
* Or a return of > 0 indicates that driver request is exceeding the number
* of irqs or MSI-X vectors available. Driver should use the returned value to
* re-send its request.
**/
int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
int nvec, bool affinity)
{
int nr_entries;
int i, j;
Expand Down Expand Up @@ -986,7 +985,27 @@ int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
dev_info(&dev->dev, "can't enable MSI-X (MSI IRQ already assigned)\n");
return -EINVAL;
}
return msix_capability_init(dev, entries, nvec);
return msix_capability_init(dev, entries, nvec, affinity);
}

/**
* pci_enable_msix - configure device's MSI-X capability structure
* @dev: pointer to the pci_dev data structure of MSI-X device function
* @entries: pointer to an array of MSI-X entries (optional)
* @nvec: number of MSI-X irqs requested for allocation by device driver
*
* Setup the MSI-X capability structure of device function with the number
* of requested irqs upon its software driver call to request for
* MSI-X mode enabled on its hardware device function. A return of zero
* indicates the successful configuration of MSI-X capability structure
* with new allocated MSI-X irqs. A return of < 0 indicates a failure.
* Or a return of > 0 indicates that driver request is exceeding the number
* of irqs or MSI-X vectors available. Driver should use the returned value to
* re-send its request.
**/
int pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, int nvec)
{
return __pci_enable_msix(dev, entries, nvec, false);
}
EXPORT_SYMBOL(pci_enable_msix);

Expand Down Expand Up @@ -1039,6 +1058,7 @@ EXPORT_SYMBOL(pci_msi_enabled);
static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
unsigned int flags)
{
bool affinity = flags & PCI_IRQ_AFFINITY;
int nvec;
int rc;

Expand Down Expand Up @@ -1067,19 +1087,17 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
nvec = maxvec;

for (;;) {
if (flags & PCI_IRQ_AFFINITY) {
dev->irq_affinity = irq_create_affinity_mask(&nvec);
if (affinity) {
nvec = irq_calc_affinity_vectors(dev->irq_affinity,
nvec);
if (nvec < minvec)
return -ENOSPC;
}

rc = msi_capability_init(dev, nvec);
rc = msi_capability_init(dev, nvec, affinity);
if (rc == 0)
return nvec;

kfree(dev->irq_affinity);
dev->irq_affinity = NULL;

if (rc < 0)
return rc;
if (rc < minvec)
Expand Down Expand Up @@ -1111,26 +1129,24 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
struct msix_entry *entries, int minvec, int maxvec,
unsigned int flags)
{
int nvec = maxvec;
int rc;
bool affinity = flags & PCI_IRQ_AFFINITY;
int rc, nvec = maxvec;

if (maxvec < minvec)
return -ERANGE;

for (;;) {
if (flags & PCI_IRQ_AFFINITY) {
dev->irq_affinity = irq_create_affinity_mask(&nvec);
if (affinity) {
nvec = irq_calc_affinity_vectors(dev->irq_affinity,
nvec);
if (nvec < minvec)
return -ENOSPC;
}

rc = pci_enable_msix(dev, entries, nvec);
rc = __pci_enable_msix(dev, entries, nvec, affinity);
if (rc == 0)
return nvec;

kfree(dev->irq_affinity);
dev->irq_affinity = NULL;

if (rc < 0)
return rc;
if (rc < minvec)
Expand Down
31 changes: 15 additions & 16 deletions kernel/irq/irqdesc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -236,25 +236,24 @@ static int alloc_descs(unsigned int start, unsigned int cnt, int node,
const struct cpumask *mask = NULL;
struct irq_desc *desc;
unsigned int flags;
int i, cpu = -1;
int i;

if (affinity && cpumask_empty(affinity))
return -EINVAL;
/* Validate affinity mask(s) */
if (affinity) {
for (i = 0, mask = affinity; i < cnt; i++, mask++) {
if (cpumask_empty(mask))
return -EINVAL;
}
}

flags = affinity ? IRQD_AFFINITY_MANAGED : 0;
mask = NULL;

for (i = 0; i < cnt; i++) {
if (affinity) {
cpu = cpumask_next(cpu, affinity);
if (cpu >= nr_cpu_ids)
cpu = cpumask_first(affinity);
node = cpu_to_node(cpu);

/*
* For single allocations we use the caller provided
* mask otherwise we use the mask of the target cpu
*/
mask = cnt == 1 ? affinity : cpumask_of(cpu);
node = cpu_to_node(cpumask_first(affinity));
mask = affinity;
affinity++;
}
desc = alloc_desc(start + i, node, flags, mask, owner);
if (!desc)
Expand Down Expand Up @@ -481,9 +480,9 @@ EXPORT_SYMBOL_GPL(irq_free_descs);
* @cnt: Number of consecutive irqs to allocate.
* @node: Preferred node on which the irq descriptor should be allocated
* @owner: Owning module (can be NULL)
* @affinity: Optional pointer to an affinity mask which hints where the
* irq descriptors should be allocated and which default
* affinities to use
* @affinity: Optional pointer to an affinity mask array of size @cnt which
* hints where the irq descriptors should be allocated and which
* default affinities to use
*
* Returns the first irq number or error code
*/
Expand Down

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