[tip: irq/core] genirq/msi: Check for invalid MSI parent domain usage

[tip-bot2 for Thomas Gleixner]

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

Commit-ID:     3e86a3a3ed031dd498e614db0fa082a58d700df9
Gitweb:        https://git.kernel.org/tip/3e86a3a3ed031dd498e614db0fa082a58d700df9
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Fri, 25 Nov 2022 00:24:19 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 05 Dec 2022 19:20:59 +01:00

genirq/msi: Check for invalid MSI parent domain usage

In the upcoming per device MSI domain concept the MSI parent domains are
not allowed to be used as regular MSI domains where the MSI allocation/free
operations are applicable.

Add appropriate checks.

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/20221124230313.806128070@xxxxxxxxxxxxx

---
 kernel/irq/msi.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index c37c0be..5939dc6 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -937,13 +937,21 @@ int msi_domain_alloc_irqs_descs_locked(struct irq_domain *domain, struct device 
 
 	lockdep_assert_held(&dev->msi.data->mutex);
 
+	if (WARN_ON_ONCE(irq_domain_is_msi_parent(domain))) {
+		ret = -EINVAL;
+		goto free;
+	}
+
+	/* Frees allocated descriptors in case of failure. */
 	ret = msi_domain_add_simple_msi_descs(info, dev, nvec);
 	if (ret)
-		return ret;
+		goto free;
 
 	ret = ops->domain_alloc_irqs(domain, dev, nvec);
-	if (ret)
-		msi_domain_free_irqs_descs_locked(domain, dev);
+	if (!ret)
+		return 0;
+free:
+	msi_domain_free_irqs_descs_locked(domain, dev);
 	return ret;
 }
 
@@ -1013,6 +1021,9 @@ void msi_domain_free_irqs_descs_locked(struct irq_domain *domain, struct device 
 
 	lockdep_assert_held(&dev->msi.data->mutex);
 
+	if (WARN_ON_ONCE(irq_domain_is_msi_parent(domain)))
+		return;
+
 	ops->domain_free_irqs(domain, dev);
 	if (ops->msi_post_free)
 		ops->msi_post_free(domain, dev);