qla2xxx: Fix shost use-after-free on device removal

Once calling scsi_host_put, be careful to not access qla_hw_data through
the Scsi_Host private data (ie, scsi_qla_host base_vha).

Fixes: fe1b806f4f71 ("qla2xxx: Refactor shutdown code so some functionality can be reused")
Cc: stable@vger.kernel.org # 3.14, 3.15, 3.16
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/qla2xxx/qla_os.c

@@ -3119,10 +3119,8 @@ qla2x00_unmap_iobases(struct qla_hw_data *ha)
 }
 
 static void
-qla2x00_clear_drv_active(scsi_qla_host_t *vha)
+qla2x00_clear_drv_active(struct qla_hw_data *ha)
 {
-	struct qla_hw_data *ha = vha->hw;
-
 	if (IS_QLA8044(ha)) {
 		qla8044_idc_lock(ha);
 		qla8044_clear_drv_active(ha);
@@ -3193,7 +3191,7 @@ qla2x00_remove_one(struct pci_dev *pdev)
 
 	scsi_host_put(base_vha->host);
 
-	qla2x00_clear_drv_active(base_vha);
+	qla2x00_clear_drv_active(ha);
 
 	qla2x00_unmap_iobases(ha);