[patch 02/10] genirq/msi: Use lock guards for MSI descriptor locking

[Thomas Gleixner <tglx@linutronix.de>]

Provide a lock guard for MSI descriptor locking and update the core code
accordingly.

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/msi.h |    3 +
 kernel/irq/msi.c    |  104 +++++++++++++++++++---------------------------------
 2 files changed, 42 insertions(+), 65 deletions(-)

--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -227,6 +227,9 @@ int msi_setup_device_data(struct device
 void msi_lock_descs(struct device *dev);
 void msi_unlock_descs(struct device *dev);
 
+DEFINE_LOCK_GUARD_1(msi_descs_lock, struct device, msi_lock_descs(_T->lock),
+		    msi_unlock_descs(_T->lock));
+
 struct msi_desc *msi_domain_first_desc(struct device *dev, unsigned int domid,
 				       enum msi_desc_filter filter);
 
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -443,7 +443,6 @@ EXPORT_SYMBOL_GPL(msi_next_desc);
 unsigned int msi_domain_get_virq(struct device *dev, unsigned int domid, unsigned int index)
 {
 	struct msi_desc *desc;
-	unsigned int ret = 0;
 	bool pcimsi = false;
 	struct xarray *xa;
 
@@ -457,7 +456,7 @@ unsigned int msi_domain_get_virq(struct
 	if (dev_is_pci(dev) && domid == MSI_DEFAULT_DOMAIN)
 		pcimsi = to_pci_dev(dev)->msi_enabled;
 
-	msi_lock_descs(dev);
+	guard(msi_descs_lock)(dev);
 	xa = &dev->msi.data->__domains[domid].store;
 	desc = xa_load(xa, pcimsi ? 0 : index);
 	if (desc && desc->irq) {
@@ -466,16 +465,12 @@ unsigned int msi_domain_get_virq(struct
 		 * PCI-MSIX and platform MSI use a descriptor per
 		 * interrupt.
 		 */
-		if (pcimsi) {
-			if (index < desc->nvec_used)
-				ret = desc->irq + index;
-		} else {
-			ret = desc->irq;
-		}
+		if (!pcimsi)
+			return desc->irq;
+		if (index < desc->nvec_used)
+			return desc->irq + index;
 	}
-
-	msi_unlock_descs(dev);
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(msi_domain_get_virq);
 
@@ -1037,25 +1032,23 @@ bool msi_create_device_irq_domain(struct
 	if (msi_setup_device_data(dev))
 		goto free_fwnode;
 
-	msi_lock_descs(dev);
-
-	if (WARN_ON_ONCE(msi_get_device_domain(dev, domid)))
-		goto fail;
-
-	if (!pops->init_dev_msi_info(dev, parent, parent, &bundle->info))
-		goto fail;
-
-	domain = __msi_create_irq_domain(fwnode, &bundle->info, IRQ_DOMAIN_FLAG_MSI_DEVICE, parent);
-	if (!domain)
-		goto fail;
-
-	domain->dev = dev;
-	dev->msi.data->__domains[domid].domain = domain;
-	msi_unlock_descs(dev);
-	return true;
+	scoped_guard(msi_descs_lock, dev) {
+		if (WARN_ON_ONCE(msi_get_device_domain(dev, domid)))
+			goto free_fwnode;
+
+		if (!pops->init_dev_msi_info(dev, parent, parent, &bundle->info))
+			goto free_fwnode;
+
+		domain = __msi_create_irq_domain(fwnode, &bundle->info, IRQ_DOMAIN_FLAG_MSI_DEVICE,
+						 parent);
+		if (!domain)
+			goto free_fwnode;
+
+		domain->dev = dev;
+		dev->msi.data->__domains[domid].domain = domain;
+		return true;
+	}
 
-fail:
-	msi_unlock_descs(dev);
 free_fwnode:
 	irq_domain_free_fwnode(fwnalloced);
 free_bundle:
@@ -1074,12 +1067,10 @@ void msi_remove_device_irq_domain(struct
 	struct msi_domain_info *info;
 	struct irq_domain *domain;
 
-	msi_lock_descs(dev);
-
+	guard(msi_descs_lock)(dev);
 	domain = msi_get_device_domain(dev, domid);
-
 	if (!domain || !irq_domain_is_msi_device(domain))
-		goto unlock;
+		return;
 
 	dev->msi.data->__domains[domid].domain = NULL;
 	info = domain->host_data;
@@ -1088,9 +1079,6 @@ void msi_remove_device_irq_domain(struct
 	irq_domain_remove(domain);
 	irq_domain_free_fwnode(fwnode);
 	kfree(container_of(info, struct msi_domain_template, info));
-
-unlock:
-	msi_unlock_descs(dev);
 }
 
 /**
@@ -1106,16 +1094,14 @@ bool msi_match_device_irq_domain(struct
 {
 	struct msi_domain_info *info;
 	struct irq_domain *domain;
-	bool ret = false;
 
-	msi_lock_descs(dev);
+	guard(msi_descs_lock)(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;
+		return info->bus_token == bus_token;
 	}
-	msi_unlock_descs(dev);
-	return ret;
+	return false;
 }
 
 static int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
@@ -1365,12 +1351,9 @@ int msi_domain_alloc_irqs_range(struct d
 		.last	= last,
 		.nirqs	= last + 1 - first,
 	};
-	int ret;
 
-	msi_lock_descs(dev);
-	ret = msi_domain_alloc_locked(dev, &ctrl);
-	msi_unlock_descs(dev);
-	return ret;
+	guard(msi_descs_lock)(dev);
+	return msi_domain_alloc_locked(dev, &ctrl);
 }
 EXPORT_SYMBOL_GPL(msi_domain_alloc_irqs_range);
 
@@ -1474,12 +1457,8 @@ struct msi_map msi_domain_alloc_irq_at(s
 				       const struct irq_affinity_desc *affdesc,
 				       union msi_instance_cookie *icookie)
 {
-	struct msi_map map;
-
-	msi_lock_descs(dev);
-	map = __msi_domain_alloc_irq_at(dev, domid, index, affdesc, icookie);
-	msi_unlock_descs(dev);
-	return map;
+	guard(msi_descs_lock)(dev);
+	return __msi_domain_alloc_irq_at(dev, domid, index, affdesc, icookie);
 }
 
 /**
@@ -1516,13 +1495,11 @@ int msi_device_domain_alloc_wired(struct
 
 	icookie.value = ((u64)type << 32) | hwirq;
 
-	msi_lock_descs(dev);
+	guard(msi_descs_lock)(dev);
 	if (WARN_ON_ONCE(msi_get_device_domain(dev, domid) != domain))
 		map.index = -EINVAL;
 	else
 		map = __msi_domain_alloc_irq_at(dev, domid, MSI_ANY_INDEX, NULL, &icookie);
-	msi_unlock_descs(dev);
-
 	return map.index >= 0 ? map.virq : map.index;
 }
 
@@ -1615,9 +1592,8 @@ static void msi_domain_free_irqs_range_l
 void msi_domain_free_irqs_range(struct device *dev, unsigned int domid,
 				unsigned int first, unsigned int last)
 {
-	msi_lock_descs(dev);
+	guard(msi_descs_lock)(dev);
 	msi_domain_free_irqs_range_locked(dev, domid, first, last);
-	msi_unlock_descs(dev);
 }
 EXPORT_SYMBOL_GPL(msi_domain_free_irqs_all);
 
@@ -1647,9 +1623,8 @@ void msi_domain_free_irqs_all_locked(str
  */
 void msi_domain_free_irqs_all(struct device *dev, unsigned int domid)
 {
-	msi_lock_descs(dev);
+	guard(msi_descs_lock)(dev);
 	msi_domain_free_irqs_all_locked(dev, domid);
-	msi_unlock_descs(dev);
 }
 
 /**
@@ -1668,12 +1643,11 @@ void msi_device_domain_free_wired(struct
 	if (WARN_ON_ONCE(!dev || !desc || domain->bus_token != DOMAIN_BUS_WIRED_TO_MSI))
 		return;
 
-	msi_lock_descs(dev);
-	if (!WARN_ON_ONCE(msi_get_device_domain(dev, MSI_DEFAULT_DOMAIN) != domain)) {
-		msi_domain_free_irqs_range_locked(dev, MSI_DEFAULT_DOMAIN, desc->msi_index,
-						  desc->msi_index);
-	}
-	msi_unlock_descs(dev);
+	guard(msi_descs_lock)(dev);
+	if (WARN_ON_ONCE(msi_get_device_domain(dev, MSI_DEFAULT_DOMAIN) != domain))
+		return;
+	msi_domain_free_irqs_range_locked(dev, MSI_DEFAULT_DOMAIN, desc->msi_index,
+					  desc->msi_index);
 }
 
 /**