cxlflash: Unmap problem state area before detaching master context

BugLink: http://bugs.launchpad.net/bugs/1588468

When operating in the PowerVM environment, the cxlflash module can
receive an error from the hypervisor indicating that there are
existing mappings in the page table for the process MMIO space.

This issue exists because term_afu() currently invokes term_mc()
before stop_afu(), allowing for the master context to be detached
first and the problem state area to be unmapped second.

To resolve this issue, stop_afu() should be called before term_mc().
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from commit 6ded8b3c)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/scsi/cxlflash/main.c

@@ -726,11 +726,11 @@ static void term_mc(struct cxlflash_cfg *cfg, enum undo_level level)
  */
 static void term_afu(struct cxlflash_cfg *cfg)
 {
-	term_mc(cfg, UNDO_START);
-
 	if (cfg->afu)
 		stop_afu(cfg);
 
+	term_mc(cfg, UNDO_START);
+
 	pr_debug("%s: returning\n", __func__);
 }
 
@@ -2502,8 +2502,8 @@ static pci_ers_result_t cxlflash_pci_error_detected(struct pci_dev *pdev,
 		if (unlikely(rc))
 			dev_err(dev, "%s: Failed to mark user contexts!(%d)\n",
 				__func__, rc);
-		term_mc(cfg, UNDO_START);
 		stop_afu(cfg);
+		term_mc(cfg, UNDO_START);
 		return PCI_ERS_RESULT_NEED_RESET;
 	case pci_channel_io_perm_failure:
 		cfg->state = STATE_FAILTERM;