[PATCH 4/4] s390/pci: Use lock guard for pci_rescan_remove_lock

[Benjamin Block <bblock@linux.ibm.com>]

There are quite a few places in the s390 architecture code for the PCI
subsystem where the kernel needs to lock `pci_rescan_remove_lock` now;
which is done by calling pci_lock_rescan_remove() to lock, and
pci_unlock_rescan_remove() to unlock the mutex.

Instead of always manually calling both functions, which induces a
certain amount of visual clutter, and in some cases of errors, cleanup,
and jumplabels more complexity, use either guard() or scoped_guard()
depending on the context.

Convert all users in the s390 architecture code for PCI.

Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
---
 arch/s390/pci/pci.c       |  8 +++----
 arch/s390/pci/pci_bus.c   |  3 +--
 arch/s390/pci/pci_event.c | 45 +++++++++++++++++----------------------
 arch/s390/pci/pci_iov.c   |  3 +--
 arch/s390/pci/pci_sysfs.c |  9 +++-----
 5 files changed, 27 insertions(+), 41 deletions(-)

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index fd16e6ad21c1..86ef1e516857 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -632,10 +632,9 @@ void pcibios_release_device(struct pci_dev *pdev)
 {
 	struct zpci_dev *zdev = to_zpci(pdev);
 
-	pci_lock_rescan_remove();
+	guard(pci_rescan_remove)();
 	zpci_unmap_resources(pdev);
 	zpci_zdev_put(zdev);
-	pci_unlock_rescan_remove();
 }
 
 int pcibios_enable_device(struct pci_dev *pdev, int mask)
@@ -1213,9 +1212,8 @@ static int __init pci_base_init(void)
 	if (rc)
 		goto out_irq;
 
-	pci_lock_rescan_remove();
-	rc = zpci_scan_devices();
-	pci_unlock_rescan_remove();
+	scoped_guard(pci_rescan_remove)
+		rc = zpci_scan_devices();
 	if (rc)
 		goto out_find;
 
diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
index 2b598222c621..c1b48b572e86 100644
--- a/arch/s390/pci/pci_bus.c
+++ b/arch/s390/pci/pci_bus.c
@@ -82,9 +82,8 @@ int zpci_bus_scan_device(struct zpci_dev *zdev)
 	if (!pdev)
 		return -ENODEV;
 
-	pci_lock_rescan_remove();
+	guard(pci_rescan_remove)();
 	pci_bus_add_device(pdev);
-	pci_unlock_rescan_remove();
 
 	return 0;
 }
diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
index edfaeed737ac..98253706b591 100644
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -342,9 +342,8 @@ static void __zpci_event_error(struct zpci_ccdf_err *ccdf)
 no_pdev:
 	if (zdev)
 		mutex_unlock(&zdev->state_lock);
-	pci_lock_rescan_remove();
+	guard(pci_rescan_remove)();
 	zpci_zdev_put(zdev);
-	pci_unlock_rescan_remove();
 }
 
 void zpci_event_error(void *data)
@@ -389,7 +388,6 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 	struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
 	bool existing_zdev = !!zdev;
 	enum zpci_state state;
-	int rc;
 
 	zpci_dbg(3, "avl fid:%x, fh:%x, pec:%x\n",
 		 ccdf->fid, ccdf->fh, ccdf->pec);
@@ -403,12 +401,11 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 			zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_CONFIGURED);
 			if (IS_ERR(zdev))
 				break;
-			pci_lock_rescan_remove();
-			rc = zpci_add_device(zdev);
-			pci_unlock_rescan_remove();
-			if (rc) {
-				kfree(zdev);
-				break;
+			scoped_guard(pci_rescan_remove) {
+				if (zpci_add_device(zdev)) {
+					kfree(zdev);
+					break;
+				}
 			}
 		} else {
 			if (zdev->state == ZPCI_FN_STATE_RESERVED)
@@ -425,12 +422,11 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 			zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_STANDBY);
 			if (IS_ERR(zdev))
 				break;
-			pci_lock_rescan_remove();
-			rc = zpci_add_device(zdev);
-			pci_unlock_rescan_remove();
-			if (rc) {
-				kfree(zdev);
-				break;
+			scoped_guard(pci_rescan_remove) {
+				if (zpci_add_device(zdev)) {
+					kfree(zdev);
+					break;
+				}
 			}
 		} else {
 			if (zdev->state == ZPCI_FN_STATE_RESERVED)
@@ -459,33 +455,30 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 			/* The 0x0304 event may immediately reserve the device */
 			if (!clp_get_state(zdev->fid, &state) &&
 			    state == ZPCI_FN_STATE_RESERVED) {
-				pci_lock_rescan_remove();
+				guard(pci_rescan_remove)();
 				zpci_device_reserved(zdev);
-				pci_unlock_rescan_remove();
 			}
 		}
 		break;
 	case 0x0306: /* 0x308 or 0x302 for multiple devices */
-		pci_lock_rescan_remove();
-		zpci_remove_reserved_devices();
-		zpci_scan_devices();
-		pci_unlock_rescan_remove();
+		scoped_guard(pci_rescan_remove) {
+			zpci_remove_reserved_devices();
+			zpci_scan_devices();
+		}
 		break;
 	case 0x0308: /* Standby -> Reserved */
 		if (!zdev)
 			break;
-		pci_lock_rescan_remove();
-		zpci_device_reserved(zdev);
-		pci_unlock_rescan_remove();
+		scoped_guard(pci_rescan_remove)
+			zpci_device_reserved(zdev);
 		break;
 	default:
 		break;
 	}
 	if (existing_zdev) {
 		mutex_unlock(&zdev->state_lock);
-		pci_lock_rescan_remove();
+		guard(pci_rescan_remove)();
 		zpci_zdev_put(zdev);
-		pci_unlock_rescan_remove();
 	}
 }
 
diff --git a/arch/s390/pci/pci_iov.c b/arch/s390/pci/pci_iov.c
index 13050ce5c3e9..1f7e4dd018e7 100644
--- a/arch/s390/pci/pci_iov.c
+++ b/arch/s390/pci/pci_iov.c
@@ -38,10 +38,9 @@ void zpci_iov_map_resources(struct pci_dev *pdev)
 
 void zpci_iov_remove_virtfn(struct pci_dev *pdev, int vfn)
 {
-	pci_lock_rescan_remove();
+	guard(pci_rescan_remove)();
 	/* Linux' vfid's start at 0 vfn at 1 */
 	pci_iov_remove_virtfn(pdev->physfn, vfn - 1);
-	pci_unlock_rescan_remove();
 }
 
 static int zpci_iov_link_virtfn(struct pci_dev *pdev, struct pci_dev *virtfn, int vfid)
diff --git a/arch/s390/pci/pci_sysfs.c b/arch/s390/pci/pci_sysfs.c
index c2444a23e26c..f5027aa95928 100644
--- a/arch/s390/pci/pci_sysfs.c
+++ b/arch/s390/pci/pci_sysfs.c
@@ -98,9 +98,9 @@ static ssize_t recover_store(struct device *dev, struct device_attribute *attr,
 	WARN_ON_ONCE(!kn);
 
 	/* Device needs to be configured and state must not change */
-	mutex_lock(&zdev->state_lock);
+	guard(mutex)(&zdev->state_lock);
 	if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
-		goto out;
+		return count;
 
 	/* device_remove_file() serializes concurrent calls ignoring all but
 	 * the first
@@ -112,15 +112,12 @@ static ssize_t recover_store(struct device *dev, struct device_attribute *attr,
 	 * Once it unblocks from pci_lock_rescan_remove() the original pdev
 	 * will already be removed.
 	 */
-	pci_lock_rescan_remove();
+	guard(pci_rescan_remove)();
 	if (pci_dev_is_added(pdev)) {
 		ret = _do_recover(pdev, zdev);
 	}
 	pci_rescan_bus(zdev->zbus->bus);
-	pci_unlock_rescan_remove();
 
-out:
-	mutex_unlock(&zdev->state_lock);
 	if (kn)
 		sysfs_unbreak_active_protection(kn);
 	return ret ? ret : count;
-- 
2.53.0