[patch V2 06/31] genirq/msi: Provide domain flags to allocate/free MSI descriptors automatically

Thomas Gleixner
2021-12-06T22:52:14Z

Provide domain info flags which tell the core to allocate simple
descriptors or to free descriptors when the interrupts are freed and
implement the required functionality.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/msi.h | 17 +++++++++++++++++
kernel/irq/msi.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 65 insertions(+)

--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -106,6 +106,8 @@ struct pci_msi_desc {
};
};

+#define MSI_MAX_INDEX ((unsigned int)USHRT_MAX)
+
/**
* struct msi_desc - Descriptor structure for MSI based interrupts
* @list: List head for management
@@ -264,6 +266,17 @@ static inline void pci_write_msi_msg(uns
#endif /* CONFIG_PCI_MSI */

int msi_add_msi_desc(struct device *dev, struct msi_desc *init_desc);
+void msi_free_msi_descs_range(struct device *dev, enum msi_desc_filter filter,
+ unsigned int first_index, unsigned int last_index);
+
+/**
+ * msi_free_msi_descs - Free MSI descriptors of a device
+ * @dev: Device to free the descriptors
+ */
+static inline void msi_free_msi_descs(struct device *dev)
+{
+ msi_free_msi_descs_range(dev, MSI_DESC_ALL, 0, MSI_MAX_INDEX);
+}

struct msi_desc *alloc_msi_entry(struct device *dev, int nvec,
const struct irq_affinity_desc *affinity);
@@ -424,6 +437,10 @@ enum {
MSI_FLAG_DEV_SYSFS = (1 << 7),
/* MSI-X entries must be contiguous */
MSI_FLAG_MSIX_CONTIGUOUS = (1 << 8),
+ /* Allocate simple MSI descriptors */
+ MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS = (1 << 9),
+ /* Free MSI descriptors */
+ MSI_FLAG_FREE_MSI_DESCS = (1 << 10),
};

int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -120,6 +120,32 @@ static int msi_add_simple_msi_descs(stru
}

/**
+ * msi_free_msi_descs_range - Free MSI descriptors of a device
+ * @dev: Device to free the descriptors
+ * @filter: Descriptor state filter
+ * @first_index: Index to start freeing from
+ * @last_index: Last index to be freed
+ */
+void msi_free_msi_descs_range(struct device *dev, enum msi_desc_filter filter,
+ unsigned int first_index, unsigned int last_index)
+{
+ struct msi_desc *desc;
+
+ lockdep_assert_held(&dev->msi.data->mutex);
+
+ msi_for_each_desc(desc, dev, filter) {
+ /*
+ * Stupid for now to handle MSI device domain until the
+ * storage is switched over to an xarray.
+ */
+ if (desc->msi_index < first_index || desc->msi_index > last_index)
+ continue;
+ list_del(&desc->list);
+ free_msi_entry(desc);
+ }
+}
+
+/**
* msi_device_has_property - Check whether a device has a specific MSI property
* @dev: Pointer to the device which is queried
* @prop: Property to check for
@@ -896,6 +922,16 @@ int __msi_domain_alloc_irqs(struct irq_d
return 0;
}

+static int msi_domain_add_simple_msi_descs(struct msi_domain_info *info,
+ struct device *dev,
+ unsigned int num_descs)
+{
+ if (!(info->flags & MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS))
+ return 0;
+
+ return msi_add_simple_msi_descs(dev, 0, num_descs);
+}
+
/**
* msi_domain_alloc_irqs_descs_locked - Allocate interrupts from a MSI interrupt domain
* @domain: The domain to allocate from
@@ -918,6 +954,10 @@ int msi_domain_alloc_irqs_descs_locked(s

lockdep_assert_held(&dev->msi.data->mutex);

+ ret = msi_domain_add_simple_msi_descs(info, dev, nvec);
+ if (ret)
+ return ret;
+
ret = ops->domain_alloc_irqs(domain, dev, nvec);
if (ret)
goto cleanup;
@@ -979,6 +1019,13 @@ void __msi_domain_free_irqs(struct irq_d
}
}

+static void msi_domain_free_msi_descs(struct msi_domain_info *info,
+ struct device *dev)
+{
+ if (info->flags & MSI_FLAG_FREE_MSI_DESCS)
+ msi_free_msi_descs(dev);
+}
+
/**
* msi_domain_free_irqs_descs_locked - Free interrupts from a MSI interrupt @domain associated to @dev
* @domain: The domain to managing the interrupts
@@ -999,6 +1046,7 @@ void msi_domain_free_irqs_descs_locked(s
if (info->flags & MSI_FLAG_DEV_SYSFS)
msi_device_destroy_sysfs(dev);
ops->domain_free_irqs(domain, dev);
+ msi_domain_free_msi_descs(info, dev);
}

/**