scsi: qla2xxx: Add option for use reserve exch for ELS

Add option to tell FW to reserve 1/2 of emergency exchanges for ELS.
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_gbl.h

@@ -148,6 +148,7 @@ extern int ql2xuctrlirq;
 extern int ql2xnvmeenable;
 extern int ql2xautodetectsfp;
 extern int ql2xenablemsix;
+extern int qla2xuseresexchforels;
 
 extern int qla2x00_loop_reset(scsi_qla_host_t *);
 extern void qla2x00_abort_all_cmds(scsi_qla_host_t *, int);

drivers/scsi/qla2xxx/qla_init.c

@@ -3348,6 +3348,12 @@ qla24xx_update_fw_options(scsi_qla_host_t *vha)
 			ha->fw_options[2] |= BIT_4;
 		else
 			ha->fw_options[2] &= ~BIT_4;
+
+		/* Reserve 1/2 of emergency exchanges for ELS.*/
+		if (qla2xuseresexchforels)
+			ha->fw_options[2] |= BIT_8;
+		else
+			ha->fw_options[2] &= ~BIT_8;
 	}
 
 	ql_dbg(ql_dbg_init, vha, 0x00e8,

drivers/scsi/qla2xxx/qla_os.c

@@ -277,6 +277,12 @@ MODULE_PARM_DESC(ql2xenablemsix,
 		 " 1 -- enable MSI-X interrupt mechanism.\n"
 		 " 2 -- enable MSI interrupt mechanism.\n");
 
+int qla2xuseresexchforels;
+module_param(qla2xuseresexchforels, int, 0444);
+MODULE_PARM_DESC(qla2xuseresexchforels,
+		 "Reserve 1/2 of emergency exchanges for ELS.\n"
+		 " 0 (default): disabled");
+
 /*
  * SCSI host template entry points
  */