NTB/msi: Switch MSI descriptor locking to lock guard()

Convert the code to use the new guard(msi_descs_lock).

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/all/20250313130321.631772601@linutronix.de

drivers/ntb/msi.c

@@ -106,10 +106,10 @@ int ntb_msi_setup_mws(struct ntb_dev *ntb)
 	if (!ntb->msi)
 		return -EINVAL;
 
-	msi_lock_descs(&ntb->pdev->dev);
-	desc = msi_first_desc(&ntb->pdev->dev, MSI_DESC_ASSOCIATED);
-	addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
-	msi_unlock_descs(&ntb->pdev->dev);
+	scoped_guard (msi_descs_lock, &ntb->pdev->dev) {
+		desc = msi_first_desc(&ntb->pdev->dev, MSI_DESC_ASSOCIATED);
+		addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
+	}
 
 	for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
 		peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
@@ -289,7 +289,7 @@ int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
 	if (!ntb->msi)
 		return -EINVAL;
 
-	msi_lock_descs(dev);
+	guard(msi_descs_lock)(dev);
 	msi_for_each_desc(entry, dev, MSI_DESC_ASSOCIATED) {
 		if (irq_has_action(entry->irq))
 			continue;
@@ -307,17 +307,11 @@ int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
 		ret = ntbm_msi_setup_callback(ntb, entry, msi_desc);
 		if (ret) {
 			devm_free_irq(&ntb->dev, entry->irq, dev_id);
-			goto unlock;
+			return ret;
 		}
-
-		ret = entry->irq;
-		goto unlock;
+		return entry->irq;
 	}
-	ret = -ENODEV;
-
-unlock:
-	msi_unlock_descs(dev);
-	return ret;
+	return -ENODEV;
 }
 EXPORT_SYMBOL(ntbm_msi_request_threaded_irq);