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Message-ID: <20221121091326.938173210@linutronix.de>
From:   Thomas Gleixner <tglx@linutronix.de>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     x86@kernel.org, Joerg Roedel <joro@8bytes.org>,
        Will Deacon <will@kernel.org>, linux-pci@vger.kernel.org,
        Bjorn Helgaas <bhelgaas@google.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jason Gunthorpe <jgg@mellanox.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Kevin Tian <kevin.tian@intel.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Ashok Raj <ashok.raj@intel.com>, Jon Mason <jdmason@kudzu.us>,
        Allen Hubbe <allenbh@gmail.com>
Subject: [patch V2 08/33] genirq/msi: Provide msi_match_device_domain()
References: <20221121083657.157152924@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Date:   Mon, 21 Nov 2022 15:37:56 +0100 (CET)
Precedence: bulk

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

--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -542,6 +542,9 @@ bool msi_create_device_irq_domain(struct
 				  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,
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -1021,6 +1021,31 @@ void msi_remove_device_irq_domain(struct
 	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)
 {