Merge tag 's390-6.16-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fixes from Alexander Gordeev:

 - Fix PCI error recovery and bring it in line with AER/EEH

* tag 's390-6.16-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/pci: Allow automatic recovery with minimal driver support
  s390/pci: Do not try re-enabling load/store if device is disabled
  s390/pci: Fix stale function handles in error handling

Author: torvalds

arch/s390/pci/pci_event.c

@@ -54,6 +54,7 @@ static inline bool ers_result_indicates_abort(pci_ers_result_t ers_res)
 	case PCI_ERS_RESULT_CAN_RECOVER:
 	case PCI_ERS_RESULT_RECOVERED:
 	case PCI_ERS_RESULT_NEED_RESET:
+	case PCI_ERS_RESULT_NONE:
 		return false;
 	default:
 		return true;
@@ -78,10 +79,6 @@ static bool is_driver_supported(struct pci_driver *driver)
 		return false;
 	if (!driver->err_handler->error_detected)
 		return false;
-	if (!driver->err_handler->slot_reset)
-		return false;
-	if (!driver->err_handler->resume)
-		return false;
 	return true;
 }
 
@@ -106,6 +103,10 @@ static pci_ers_result_t zpci_event_do_error_state_clear(struct pci_dev *pdev,
 	struct zpci_dev *zdev = to_zpci(pdev);
 	int rc;
 
+	/* The underlying device may have been disabled by the event */
+	if (!zdev_enabled(zdev))
+		return PCI_ERS_RESULT_NEED_RESET;
+
 	pr_info("%s: Unblocking device access for examination\n", pci_name(pdev));
 	rc = zpci_reset_load_store_blocked(zdev);
 	if (rc) {
@@ -114,16 +115,18 @@ static pci_ers_result_t zpci_event_do_error_state_clear(struct pci_dev *pdev,
 		return PCI_ERS_RESULT_NEED_RESET;
 	}
 
-	if (driver->err_handler->mmio_enabled) {
+	if (driver->err_handler->mmio_enabled)
 		ers_res = driver->err_handler->mmio_enabled(pdev);
-		if (ers_result_indicates_abort(ers_res)) {
-			pr_info("%s: Automatic recovery failed after MMIO re-enable\n",
-				pci_name(pdev));
-			return ers_res;
-		} else if (ers_res == PCI_ERS_RESULT_NEED_RESET) {
-			pr_debug("%s: Driver needs reset to recover\n", pci_name(pdev));
-			return ers_res;
-		}
+	else
+		ers_res = PCI_ERS_RESULT_NONE;
+
+	if (ers_result_indicates_abort(ers_res)) {
+		pr_info("%s: Automatic recovery failed after MMIO re-enable\n",
+			pci_name(pdev));
+		return ers_res;
+	} else if (ers_res == PCI_ERS_RESULT_NEED_RESET) {
+		pr_debug("%s: Driver needs reset to recover\n", pci_name(pdev));
+		return ers_res;
 	}
 
 	pr_debug("%s: Unblocking DMA\n", pci_name(pdev));
@@ -150,7 +153,12 @@ static pci_ers_result_t zpci_event_do_reset(struct pci_dev *pdev,
 		return ers_res;
 	}
 	pdev->error_state = pci_channel_io_normal;
-	ers_res = driver->err_handler->slot_reset(pdev);
+
+	if (driver->err_handler->slot_reset)
+		ers_res = driver->err_handler->slot_reset(pdev);
+	else
+		ers_res = PCI_ERS_RESULT_NONE;
+
 	if (ers_result_indicates_abort(ers_res)) {
 		pr_info("%s: Automatic recovery failed after slot reset\n", pci_name(pdev));
 		return ers_res;
@@ -214,7 +222,7 @@ static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev)
 		goto out_unlock;
 	}
 
-	if (ers_res == PCI_ERS_RESULT_CAN_RECOVER) {
+	if (ers_res != PCI_ERS_RESULT_NEED_RESET) {
 		ers_res = zpci_event_do_error_state_clear(pdev, driver);
 		if (ers_result_indicates_abort(ers_res)) {
 			status_str = "failed (abort on MMIO enable)";
@@ -225,6 +233,16 @@ static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev)
 	if (ers_res == PCI_ERS_RESULT_NEED_RESET)
 		ers_res = zpci_event_do_reset(pdev, driver);
 
+	/*
+	 * ers_res can be PCI_ERS_RESULT_NONE either because the driver
+	 * decided to return it, indicating that it abstains from voting
+	 * on how to recover, or because it didn't implement the callback.
+	 * Both cases assume, that if there is nothing else causing a
+	 * disconnect, we recovered successfully.
+	 */
+	if (ers_res == PCI_ERS_RESULT_NONE)
+		ers_res = PCI_ERS_RESULT_RECOVERED;
+
 	if (ers_res != PCI_ERS_RESULT_RECOVERED) {
 		pr_err("%s: Automatic recovery failed; operator intervention is required\n",
 		       pci_name(pdev));
@@ -273,6 +291,8 @@ static void __zpci_event_error(struct zpci_ccdf_err *ccdf)
 	struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
 	struct pci_dev *pdev = NULL;
 	pci_ers_result_t ers_res;
+	u32 fh = 0;
+	int rc;
 
 	zpci_dbg(3, "err fid:%x, fh:%x, pec:%x\n",
 		 ccdf->fid, ccdf->fh, ccdf->pec);
@@ -281,6 +301,15 @@ static void __zpci_event_error(struct zpci_ccdf_err *ccdf)
 
 	if (zdev) {
 		mutex_lock(&zdev->state_lock);
+		rc = clp_refresh_fh(zdev->fid, &fh);
+		if (rc)
+			goto no_pdev;
+		if (!fh || ccdf->fh != fh) {
+			/* Ignore events with stale handles */
+			zpci_dbg(3, "err fid:%x, fh:%x (stale %x)\n",
+				 ccdf->fid, fh, ccdf->fh);
+			goto no_pdev;
+		}
 		zpci_update_fh(zdev, ccdf->fh);
 		if (zdev->zbus->bus)
 			pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);