genirq/msi: Provide msi_device_populate/destroy_sysfs()

Add new allocation functions which can be activated by domain info
flags. They store the groups pointer in struct msi_device_data.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221813.988659194@linutronix.de

include/linux/msi.h

@@ -56,6 +56,8 @@ struct irq_data;
 struct msi_desc;
 struct pci_dev;
 struct platform_msi_priv_data;
+struct attribute_group;
+
 void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
 #ifdef CONFIG_GENERIC_MSI_IRQ
 void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg);
@@ -174,9 +176,11 @@ struct msi_desc {
 /**
  * msi_device_data - MSI per device data
  * @properties:		MSI properties which are interesting to drivers
+ * @attrs:		Pointer to the sysfs attribute group
  */
 struct msi_device_data {
 	unsigned long			properties;
+	const struct attribute_group    **attrs;
 };
 
 int msi_setup_device_data(struct device *dev);

kernel/irq/msi.c

@@ -199,6 +199,20 @@ const struct attribute_group **msi_populate_sysfs(struct device *dev)
 	return ERR_PTR(ret);
 }
 
+/**
+ * msi_device_populate_sysfs - Populate msi_irqs sysfs entries for a device
+ * @dev:	The device (PCI, platform etc) which will get sysfs entries
+ */
+int msi_device_populate_sysfs(struct device *dev)
+{
+	const struct attribute_group **group = msi_populate_sysfs(dev);
+
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+	dev->msi.data->attrs = group;
+	return 0;
+}
+
 /**
  * msi_destroy_sysfs - Destroy msi_irqs sysfs entries for devices
  * @dev:		The device(PCI, platform etc) who will remove sysfs entries
@@ -225,6 +239,17 @@ void msi_destroy_sysfs(struct device *dev, const struct attribute_group **msi_ir
 		kfree(msi_irq_groups);
 	}
 }
+
+/**
+ * msi_device_destroy_sysfs - Destroy msi_irqs sysfs entries for a device
+ * @dev:		The device (PCI, platform etc) for which to remove
+ *			sysfs entries
+ */
+void msi_device_destroy_sysfs(struct device *dev)
+{
+	msi_destroy_sysfs(dev, dev->msi.data->attrs);
+	dev->msi.data->attrs = NULL;
+}
 #endif
 
 #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
@@ -672,8 +697,19 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 {
 	struct msi_domain_info *info = domain->host_data;
 	struct msi_domain_ops *ops = info->ops;
+	int ret;
+
+	ret = ops->domain_alloc_irqs(domain, dev, nvec);
+	if (ret)
+		return ret;
+
+	if (!(info->flags & MSI_FLAG_DEV_SYSFS))
+		return 0;
 
-	return ops->domain_alloc_irqs(domain, dev, nvec);
+	ret = msi_device_populate_sysfs(dev);
+	if (ret)
+		msi_domain_free_irqs(domain, dev);
+	return ret;
 }
 
 void __msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
@@ -712,7 +748,9 @@ void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
 	struct msi_domain_info *info = domain->host_data;
 	struct msi_domain_ops *ops = info->ops;
 
-	return ops->domain_free_irqs(domain, dev);
+	if (info->flags & MSI_FLAG_DEV_SYSFS)
+		msi_device_destroy_sysfs(dev);
+	ops->domain_free_irqs(domain, dev);
 }
 
 /**