[SCSI] bfa: Add support for IO throttling at port level

Add capability to limit the number of exchanges on a port to
avoid queue-full conditions from the target side.

Signed-off-by: Sudarsana Reddy Kalluru <[e-mail]>
Signed-off-by: Krishna Gudipati <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/bfa/bfa_core.c

···
 		cfg_info->single_msix_vec = 1;
 	cfg_info->endian_sig = BFI_IOC_ENDIAN_SIG;
 	cfg_info->num_cqs = cfg->fwcfg.num_cqs;
-	cfg_info->num_ioim_reqs = cpu_to_be16(cfg->fwcfg.num_ioim_reqs);
+	cfg_info->num_ioim_reqs = cpu_to_be16(bfa_fcpim_get_throttle_cfg(bfa,
+					       cfg->fwcfg.num_ioim_reqs));
 	cfg_info->num_fwtio_reqs = cpu_to_be16(cfg->fwcfg.num_fwtio_reqs);
 
 	bfa_dma_be_addr_set(cfg_info->cfgrsp_addr, iocfc->cfgrsp_dma.pa);
···
 static void
 bfa_iocfc_res_recfg(struct bfa_s *bfa, struct bfa_iocfc_fwcfg_s *fwcfg)
 {
+	struct bfa_iocfc_s	*iocfc   = &bfa->iocfc;
+	struct bfi_iocfc_cfg_s	*cfg_info = iocfc->cfginfo;
+
 	bfa_fcxp_res_recfg(bfa, fwcfg->num_fcxp_reqs);
 	bfa_uf_res_recfg(bfa, fwcfg->num_uf_bufs);
 	bfa_rport_res_recfg(bfa, fwcfg->num_rports);
-	bfa_fcp_res_recfg(bfa, fwcfg->num_ioim_reqs);
+	bfa_fcp_res_recfg(bfa, cpu_to_be16(cfg_info->num_ioim_reqs),
+			  fwcfg->num_ioim_reqs);
 	bfa_tskim_res_recfg(bfa, fwcfg->num_tskim_reqs);
 }
 

drivers/scsi/bfa/bfa_defs_svc.h

···
 	struct bfa_lun_mask_s	lun_list[MAX_LUN_MASK_CFG];
 };
 
+struct bfa_throttle_cfg_s {
+	u16	is_valid;
+	u16	value;
+	u32	rsvd;
+};
+
+struct bfa_defs_fcpim_throttle_s {
+	u16	max_value;
+	u16	cur_value;
+	u16	cfg_value;
+	u16	rsvd;
+};
+
 /*
  *      Physical port configuration
  */

drivers/scsi/bfa/bfa_fcpim.c

···
 	struct bfa_mem_dma_s *seg_ptr;
 	u16	idx, nsegs, num_io_req;
 
+	fcp->max_ioim_reqs = cfg->fwcfg.num_ioim_reqs;
 	fcp->num_ioim_reqs = cfg->fwcfg.num_ioim_reqs;
 	fcp->num_fwtio_reqs  = cfg->fwcfg.num_fwtio_reqs;
 	fcp->num_itns   = cfg->fwcfg.num_rports;
···
 		bfa_iocfc_set_snsbase(bfa, idx, fcp->snsbase[idx].pa);
 	}
 
+	fcp->throttle_update_required = 1;
 	bfa_fcpim_attach(fcp, bfad, cfg, pcidev);
 
 	bfa_iotag_attach(fcp);
···
 {
 	struct bfa_fcp_mod_s *fcp = BFA_FCP_MOD(bfa);
 
-	/* Enqueue unused ioim resources to free_q */
-	list_splice_tail_init(&fcp->iotag_unused_q, &fcp->iotag_ioim_free_q);
-
 	bfa_fcpim_iocdisable(fcp);
 }
 
 void
-bfa_fcp_res_recfg(struct bfa_s *bfa, u16 num_ioim_fw)
+bfa_fcp_res_recfg(struct bfa_s *bfa, u16 num_ioim_fw, u16 max_ioim_fw)
 {
 	struct bfa_fcp_mod_s	*mod = BFA_FCP_MOD(bfa);
 	struct list_head	*qe;
 	int	i;
 
+	/* Update io throttle value only once during driver load time */
+	if (!mod->throttle_update_required)
+		return;
+
 	for (i = 0; i < (mod->num_ioim_reqs - num_ioim_fw); i++) {
 		bfa_q_deq_tail(&mod->iotag_ioim_free_q, &qe);
 		list_add_tail(qe, &mod->iotag_unused_q);
 	}
+
+	if (mod->num_ioim_reqs != num_ioim_fw) {
+		bfa_trc(bfa, mod->num_ioim_reqs);
+		bfa_trc(bfa, num_ioim_fw);
+	}
+
+	mod->max_ioim_reqs = max_ioim_fw;
+	mod->num_ioim_reqs = num_ioim_fw;
+	mod->throttle_update_required = 0;
 }
 
 void
···
 	}
 
 	bfa_mem_kva_curp(fcp) = (u8 *) iotag;
+}
+
+
+/**
+ * To send config req, first try to use throttle value from flash
+ * If 0, then use driver parameter
+ * We need to use min(flash_val, drv_val) because
+ * memory allocation was done based on this cfg'd value
+ */
+u16
+bfa_fcpim_get_throttle_cfg(struct bfa_s *bfa, u16 drv_cfg_param)
+{
+	u16 tmp;
+	struct bfa_fcp_mod_s *fcp = BFA_FCP_MOD(bfa);
+
+	/*
+	 * If throttle value from flash is already in effect after driver is
+	 * loaded then until next load, always return current value instead
+	 * of actual flash value
+	 */
+	if (!fcp->throttle_update_required)
+		return (u16)fcp->num_ioim_reqs;
+
+	tmp = bfa_dconf_read_data_valid(bfa) ? bfa_fcpim_read_throttle(bfa) : 0;
+	if (!tmp || (tmp > drv_cfg_param))
+		tmp = drv_cfg_param;
+
+	return tmp;
+}
+
+bfa_status_t
+bfa_fcpim_write_throttle(struct bfa_s *bfa, u16 value)
+{
+	if (!bfa_dconf_get_min_cfg(bfa)) {
+		BFA_DCONF_MOD(bfa)->dconf->throttle_cfg.value = value;
+		BFA_DCONF_MOD(bfa)->dconf->throttle_cfg.is_valid = 1;
+		return BFA_STATUS_OK;
+	}
+
+	return BFA_STATUS_FAILED;
+}
+
+u16
+bfa_fcpim_read_throttle(struct bfa_s *bfa)
+{
+	struct bfa_throttle_cfg_s *throttle_cfg =
+			&(BFA_DCONF_MOD(bfa)->dconf->throttle_cfg);
+
+	return ((!bfa_dconf_get_min_cfg(bfa)) ?
+	       ((throttle_cfg->is_valid == 1) ? (throttle_cfg->value) : 0) : 0);
+}
+
+bfa_status_t
+bfa_fcpim_throttle_set(struct bfa_s *bfa, u16 value)
+{
+	/* in min cfg no commands should run. */
+	if ((bfa_dconf_get_min_cfg(bfa) == BFA_TRUE) ||
+	    (!bfa_dconf_read_data_valid(bfa)))
+		return BFA_STATUS_FAILED;
+
+	bfa_fcpim_write_throttle(bfa, value);
+
+	return bfa_dconf_update(bfa);
+}
+
+bfa_status_t
+bfa_fcpim_throttle_get(struct bfa_s *bfa, void *buf)
+{
+	struct bfa_fcpim_s *fcpim = BFA_FCPIM(bfa);
+	struct bfa_defs_fcpim_throttle_s throttle;
+
+	if ((bfa_dconf_get_min_cfg(bfa) == BFA_TRUE) ||
+	    (!bfa_dconf_read_data_valid(bfa)))
+		return BFA_STATUS_FAILED;
+
+	memset(&throttle, 0, sizeof(struct bfa_defs_fcpim_throttle_s));
+
+	throttle.cur_value = (u16)(fcpim->fcp->num_ioim_reqs);
+	throttle.cfg_value = bfa_fcpim_read_throttle(bfa);
+	if (!throttle.cfg_value)
+		throttle.cfg_value = throttle.cur_value;
+	throttle.max_value = (u16)(fcpim->fcp->max_ioim_reqs);
+	memcpy(buf, &throttle, sizeof(struct bfa_defs_fcpim_throttle_s));
+
+	return BFA_STATUS_OK;
 }

drivers/scsi/bfa/bfa_fcpim.h

···
 		void (*isr)(struct bfa_s *bfa, struct bfi_msg_s *m));
 void bfa_itn_isr(struct bfa_s *bfa, struct bfi_msg_s *m);
 void bfa_iotag_attach(struct bfa_fcp_mod_s *fcp);
-void bfa_fcp_res_recfg(struct bfa_s *bfa, u16 num_ioim_fw);
+void bfa_fcp_res_recfg(struct bfa_s *bfa, u16 num_ioim_fw, u16 max_ioim_fw);
 
 #define BFA_FCP_MOD(_hal)	(&(_hal)->modules.fcp_mod)
 #define BFA_MEM_FCP_KVA(__bfa)	(&(BFA_FCP_MOD(__bfa)->kva_seg))
···
 	struct list_head	iotag_unused_q;	/* unused IO resources*/
 	struct bfa_iotag_s	*iotag_arr;
 	struct bfa_itn_s	*itn_arr;
+	int			max_ioim_reqs;
 	int			num_ioim_reqs;
 	int			num_fwtio_reqs;
 	int			num_itns;
···
 	struct bfa_fcpim_s	fcpim;
 	struct bfa_mem_dma_s	dma_seg[BFA_FCP_DMA_SEGS];
 	struct bfa_mem_kva_s	kva_seg;
+	int			throttle_update_required;
 };
 
 /*
···
 bfa_status_t	bfa_fcpim_lunmask_add(struct bfa_s *bfa, u16 vf_id,
 				wwn_t *pwwn, wwn_t rpwwn, struct scsi_lun lun);
 bfa_status_t	bfa_fcpim_lunmask_clear(struct bfa_s *bfa);
+u16		bfa_fcpim_read_throttle(struct bfa_s *bfa);
+bfa_status_t	bfa_fcpim_write_throttle(struct bfa_s *bfa, u16 value);
+bfa_status_t	bfa_fcpim_throttle_set(struct bfa_s *bfa, u16 value);
+bfa_status_t	bfa_fcpim_throttle_get(struct bfa_s *bfa, void *buf);
+u16     bfa_fcpim_get_throttle_cfg(struct bfa_s *bfa, u16 drv_cfg_param);
 
 #endif /* __BFA_FCPIM_H__ */

drivers/scsi/bfa/bfa_fcs_rport.c

···
 	struct bfa_rport_qos_attr_s qos_attr;
 	struct bfa_fcs_lport_s *port = rport->port;
 	bfa_port_speed_t rport_speed = rport->rpf.rpsc_speed;
+	struct bfa_port_attr_s port_attr;
+
+	bfa_fcport_get_attr(rport->fcs->bfa, &port_attr);
 
 	memset(rport_attr, 0, sizeof(struct bfa_rport_attr_s));
 	memset(&qos_attr, 0, sizeof(struct bfa_rport_qos_attr_s));
···
 			rport_speed =
 				bfa_fcport_get_ratelim_speed(rport->fcs->bfa);
 
-		if (rport_speed < bfa_fcs_lport_get_rport_max_speed(port))
+		if ((bfa_fcs_lport_get_rport_max_speed(port) !=
+		    BFA_PORT_SPEED_UNKNOWN) && (rport_speed < port_attr.speed))
 			rport_attr->trl_enforced = BFA_TRUE;
 	}
 }

drivers/scsi/bfa/bfa_ioc.h

···
 struct bfa_dconf_s {
 	struct bfa_dconf_hdr_s		hdr;
 	struct bfa_lunmask_cfg_s	lun_mask;
+	struct bfa_throttle_cfg_s	throttle_cfg;
 };
 #pragma pack()
 
···
 #define bfa_dconf_read_data_valid(__bfa)	\
 	(BFA_DCONF_MOD(__bfa)->read_data_valid)
 #define BFA_DCONF_UPDATE_TOV	5000	/* memtest timeout in msec */
+#define bfa_dconf_get_min_cfg(__bfa)	\
+	(BFA_DCONF_MOD(__bfa)->min_cfg)
 
 void	bfa_dconf_modinit(struct bfa_s *bfa);
 void	bfa_dconf_modexit(struct bfa_s *bfa);

drivers/scsi/bfa/bfad_bsg.c

···
 	return 0;
 }
 
+int
+bfad_iocmd_fcpim_throttle_query(struct bfad_s *bfad, void *cmd)
+{
+	struct bfa_bsg_fcpim_throttle_s *iocmd =
+			(struct bfa_bsg_fcpim_throttle_s *)cmd;
+	unsigned long   flags;
+
+	spin_lock_irqsave(&bfad->bfad_lock, flags);
+	iocmd->status = bfa_fcpim_throttle_get(&bfad->bfa,
+				(void *)&iocmd->throttle);
+	spin_unlock_irqrestore(&bfad->bfad_lock, flags);
+
+	return 0;
+}
+
+int
+bfad_iocmd_fcpim_throttle_set(struct bfad_s *bfad, void *cmd)
+{
+	struct bfa_bsg_fcpim_throttle_s *iocmd =
+			(struct bfa_bsg_fcpim_throttle_s *)cmd;
+	unsigned long	flags;
+
+	spin_lock_irqsave(&bfad->bfad_lock, flags);
+	iocmd->status = bfa_fcpim_throttle_set(&bfad->bfa,
+				iocmd->throttle.cfg_value);
+	spin_unlock_irqrestore(&bfad->bfad_lock, flags);
+
+	return 0;
+}
+
 static int
 bfad_iocmd_handler(struct bfad_s *bfad, unsigned int cmd, void *iocmd,
 		unsigned int payload_len)
···
 	case IOCMD_FCPIM_LUNMASK_ADD:
 	case IOCMD_FCPIM_LUNMASK_DELETE:
 		rc = bfad_iocmd_fcpim_cfg_lunmask(bfad, iocmd, cmd);
+		break;
+	case IOCMD_FCPIM_THROTTLE_QUERY:
+		rc = bfad_iocmd_fcpim_throttle_query(bfad, iocmd);
+		break;
+	case IOCMD_FCPIM_THROTTLE_SET:
+		rc = bfad_iocmd_fcpim_throttle_set(bfad, iocmd);
 		break;
 	default:
 		rc = -EINVAL;

drivers/scsi/bfa/bfad_bsg.h

···
 	IOCMD_DIAG_DPORT_DISABLE,
 	IOCMD_DIAG_DPORT_GET_STATE,
 	IOCMD_QOS_SET_BW,
+	IOCMD_FCPIM_THROTTLE_QUERY,
+	IOCMD_FCPIM_THROTTLE_SET
 };
 
 struct bfa_bsg_gen_s {
···
 	wwn_t		pwwn;
 	wwn_t		rpwwn;
 	struct scsi_lun	lun;
+};
+
+struct bfa_bsg_fcpim_throttle_s {
+	bfa_status_t	status;
+	u16		bfad_num;
+	u16		vf_id;
+	struct bfa_defs_fcpim_throttle_s throttle;
 };
 
 struct bfa_bsg_fcpt_s {