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@linutronix.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221124230313.806128070@linutronix.de

diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index c37c0be4d6464d0f1bd4b4d4e56d24d50d0eeb95..5939dc613559550eecab2fb54421e28973461e8f 100644 (file)
--- 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);