[tip: irq/core] genirq/msi: Provide msi_match_device_domain()

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     26e91b75bf6108550035355c835bf0c93c885b61
Gitweb:        https://git.kernel.org/tip/26e91b75bf6108550035355c835bf0c93c885b61
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Fri, 25 Nov 2022 00:25:57 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 05 Dec 2022 19:21:01 +01:00

genirq/msi: Provide msi_match_device_domain()

Provide an interface to match a per device domain bus token. This allows to
query which type of domain is installed for a particular domain id. Will be
used for PCI to avoid frequent create/remove cycles for the MSI resp. MSI-X
domains.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221124232325.738047902@xxxxxxxxxxxxx

---
 include/linux/msi.h |  3 +++
 kernel/irq/msi.c    | 25 +++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index ef46a3e..b4ab005 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -553,6 +553,9 @@ bool msi_create_device_irq_domain(struct device *dev, unsigned int domid,
 				  void *chip_data);
 void msi_remove_device_irq_domain(struct device *dev, unsigned int domid);
 
+bool msi_match_device_irq_domain(struct device *dev, unsigned int domid,
+				 enum irq_domain_bus_token bus_token);
+
 int msi_domain_alloc_irqs_range_locked(struct device *dev, unsigned int domid,
 				       unsigned int first, unsigned int last);
 int msi_domain_alloc_irqs_range(struct device *dev, unsigned int domid,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 8b415bd..7449998 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -986,6 +986,31 @@ unlock:
 	msi_unlock_descs(dev);
 }
 
+/**
+ * msi_match_device_irq_domain - Match a device irq domain against a bus token
+ * @dev:	Pointer to the device
+ * @domid:	Domain id
+ * @bus_token:	Bus token to match against the domain bus token
+ *
+ * Return: True if device domain exists and bus tokens match.
+ */
+bool msi_match_device_irq_domain(struct device *dev, unsigned int domid,
+				 enum irq_domain_bus_token bus_token)
+{
+	struct msi_domain_info *info;
+	struct irq_domain *domain;
+	bool ret = false;
+
+	msi_lock_descs(dev);
+	domain = msi_get_device_domain(dev, domid);
+	if (domain && irq_domain_is_msi_device(domain)) {
+		info = domain->host_data;
+		ret = info->bus_token == bus_token;
+	}
+	msi_unlock_descs(dev);
+	return ret;
+}
+
 int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
 			    int nvec, msi_alloc_info_t *arg)
 {