Alexander, what do you think about the version below? Survived
quick testing with nvme so far.
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index a510484..cee3962 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1121,98 +1121,131 @@ int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
}
EXPORT_SYMBOL(pci_enable_msix_range);
-static int __pci_enable_msix(struct pci_dev *dev, int nr_vecs)
+static int __pci_enable_msi(struct pci_dev *dev, unsigned int min_vecs,
+ unsigned int max_vecs)
{
- struct msix_entry *msix_entries;
- int ret, i;
+ int nr_vecs, i;
- msix_entries = kcalloc(nr_vecs, sizeof(struct msix_entry), GFP_KERNEL);
- if (!msix_entries)
- return -ENOMEM;
+ nr_vecs = pci_msi_vec_count(dev);
+ if (nr_vecs <= 0)
+ return -EINVAL;
+ max_vecs = min_t(unsigned int, max_vecs, nr_vecs);
- for (i = 0; i < nr_vecs; i++)
- msix_entries[i].entry = i;
+ nr_vecs = pci_enable_msi_range(dev, min_vecs, max_vecs);
+ if (nr_vecs > 1) {
+ dev->irqs = kcalloc(nr_vecs, sizeof(u32), GFP_KERNEL);
+ if (!dev->irqs) {
+ pci_disable_msi(dev);
+ return -ENOMEM;
+ }
- ret = msix_capability_init(dev, msix_entries, nr_vecs);
- if (ret == 0) {
for (i = 0; i < nr_vecs; i++)
- dev->irqs[i] = msix_entries[i].vector;
+ dev->irqs[i] = dev->irq + i;
+ } else if (nr_vecs == 1) {
+ dev->irqs = &dev->irq;
}
- kfree(msix_entries);
- return ret;
+ WARN_ON_ONCE(nr_vecs == 0);
+ return nr_vecs;
}
-static int __pci_enable_msi(struct pci_dev *dev, int nr_vecs)
+static int __pci_enable_msix(struct pci_dev *dev, unsigned int min_vecs,
+ unsigned int max_vecs)
{
- int ret, i;
+ struct msix_entry *msix_entries;
+ int nr_vecs, i;
- ret = msi_capability_init(dev, nr_vecs);
- if (ret == 0) {
- for (i = 0; i < nr_vecs; i++)
- dev->irqs[i] = dev->irq + i;
+ nr_vecs = pci_msix_vec_count(dev);
+ if (nr_vecs <= 0)
+ return -EINVAL;
+ max_vecs = min_t(unsigned int, max_vecs, nr_vecs);
+
+ msix_entries = kcalloc(max_vecs, sizeof(struct msix_entry), GFP_KERNEL);
+ if (!msix_entries)
+ return -ENOMEM;
+
+ for (i = 0; i < max_vecs; i++)
+ msix_entries[i].entry = i;
+
+ nr_vecs = pci_enable_msix_range(dev, msix_entries, min_vecs, max_vecs);
+ if (nr_vecs < 0)
+ goto out_free_entries;
+
+ dev->irqs = kcalloc(nr_vecs, sizeof(u32), GFP_KERNEL);
+ if (!dev->irqs) {
+ pci_disable_msix(dev);
+ nr_vecs = -ENOMEM;
+ goto out_free_entries;
}
- return ret;
+ for (i = 0; i < nr_vecs; i++)
+ dev->irqs[i] = msix_entries[i].vector;
+
+out_free_entries:
+ WARN_ON_ONCE(nr_vecs == 0);
+ kfree(msix_entries);
+ return nr_vecs;
}
/**
* pci_alloc_irq_vectors - allocate multiple IRQs for a device
* @dev: PCI device to operate on
- * @nr_vecs: number of vectors to operate on
+ * @min_vecs: minimum vectors required
+ * @max_vecs: maximum vectors requested
* @flags: flags or quirks for the allocation
*
- * Allocate @nr_vecs interrupt vectors for @dev, using MSI-X or MSI
- * vectors if available, and fall back to a single legacy vector
- * if neither is available. Return the number of vectors allocated
- * (which might be smaller than @nr_vecs) if successful, or a negative
- * error code on error. The Linux irq numbers for the allocated
- * vectors are stored in pdev->irqs.
+ * Allocate up to @max_vecs interrupt vectors for @dev, using MSI-X or MSI
+ * vectors if available, and fall back to a single legacy vector if neither
+ * is available. Return the number of vectors allocated (which might be
+ * smaller than @max_vecs) if successful, or a negative error code on error.
+ *
+ * The Linux irq numbers for the allocated vectors are stored in pdev->irqs.
+ *
+ * If @min_vecs is set to a number bigger than zero the function will fail
+ * with -%ENOSPC if les than @min_vecs vectors are available.
*/
-int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int nr_vecs,
- unsigned int flags)
+int pci_alloc_irq_vectors_range(struct pci_dev *dev, unsigned int min_vecs,
+ unsigned int max_vecs, unsigned int flags)
{
- unsigned int ret;
-
+ if (WARN_ON_ONCE(min_vecs == 0))
+ return -EINVAL;
+ if (WARN_ON_ONCE(max_vecs < min_vecs))
+ return -EINVAL;
if (WARN_ON_ONCE(dev->msi_enabled || dev->msix_enabled))
return -EINVAL;
- if (!pci_msi_supported(dev, 1))
- goto use_legacy_irq;
-
- if (dev->msix_cap && !(flags & PCI_IRQ_NOMSIX))
- nr_vecs = min_t(unsigned int, nr_vecs, pci_msix_vec_count(dev));
- else if (dev->msi_cap)
- nr_vecs = min_t(unsigned int, nr_vecs, pci_msi_vec_count(dev));
- else
- goto use_legacy_irq;
-
- dev->irqs = kcalloc(nr_vecs, sizeof(u32), GFP_KERNEL);
- if (!dev->irqs)
- return -ENOMEM;
-
- if (dev->msix_cap && !(flags & PCI_IRQ_NOMSIX))
- ret = __pci_enable_msix(dev, nr_vecs);
- else
- ret = __pci_enable_msi(dev, nr_vecs);
- if (ret)
- goto out_free_irqs;
-
- return 0;
+ if (pci_msi_supported(dev, 1)) {
+ if (dev->msix_cap && !(flags & PCI_IRQ_NOMSIX)) {
+ int ret = __pci_enable_msix(dev, min_vecs, max_vecs);
+ if (ret > 0)
+ return ret;
+ }
+ if (dev->msi_cap) {
+ int ret = __pci_enable_msi(dev, min_vecs, max_vecs);
+ if (ret > 0)
+ return ret;
+ }
+ }
-out_free_irqs:
- kfree(dev->irqs);
-use_legacy_irq:
+ /* no MSI or MSI-X vectors available, use the legacy IRQ: */
dev->irqs = &dev->irq;
return 1;
}
+EXPORT_SYMBOL(pci_alloc_irq_vectors_range);
+
+int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int nr_vecs,
+ unsigned int flags)
+{
+ return pci_alloc_irq_vectors_range(dev, 1, nr_vecs, flags);
+}
EXPORT_SYMBOL(pci_alloc_irq_vectors);
/**
* pci_free_irq_vectors - free previously allocated IRQs for a device
* @dev: PCI device to operate on
*
- * Undoes the allocations and enabling in pci_alloc_irq_vectors().
+ * Undoes the allocations and enabling in pci_alloc_irq_vectors() or
+ * pci_alloc_irq_vectors_range().
*/
void pci_free_irq_vectors(struct pci_dev *dev)
{
diff --git a/include/linux/pci.h b/include/linux/pci.h
index e201d0d..cd5800a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1289,6 +1289,8 @@ static inline int pci_enable_msix_exact(struct pci_dev *dev,
int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int nr_vecs,
unsigned int flags);
+int pci_alloc_irq_vectors_range(struct pci_dev *dev, unsigned int min_vecs,
+ unsigned int max_vecs, unsigned int flags);
void pci_free_irq_vectors(struct pci_dev *dev);
#else
static inline int pci_msi_vec_count(struct pci_dev *dev) { return -ENOSYS; }
--
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