[SCSI] fnic: fnic Driver Tuneables Exposed through CLI

Introduced module params to provide dynamic way of configuring
queue depth.

Added support to get max io throttle count through UCSM to
configure maximum outstanding IOs supported by fnic and push
that value to scsi mid-layer.

Supported IO throttle values:

UCSM IO THROTTLE VALUE FNIC MAX OUTSTANDING IOS
------------------------------------------------------
16 (Default) 2048
<= 256 256
> 256 <ucsm value>

Signed-off-by: Hiral Patel <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/fnic/fnic.h

···
 #define DFX                     DRV_NAME "%d: "
 
 #define DESC_CLEAN_LOW_WATERMARK 8
+#define FNIC_UCSM_DFLT_THROTTLE_CNT_BLD	16 /* UCSM default throttle count */
+#define FNIC_MIN_IO_REQ			256 /* Min IO throttle count */
 #define FNIC_MAX_IO_REQ		2048 /* scsi_cmnd tag map entries */
 #define	FNIC_IO_LOCKS		64 /* IO locks: power of 2 */
 #define FNIC_DFLT_QUEUE_DEPTH	32
···
 	char name[IFNAMSIZ];
 	struct timer_list notify_timer; /* used for MSI interrupts */
 
+	unsigned int fnic_max_tag_id;
 	unsigned int err_intr_offset;
 	unsigned int link_intr_offset;
 

drivers/scsi/fnic/fnic_main.c

···
 MODULE_PARM_DESC(fnic_trace_max_pages, "Total allocated memory pages "
 					"for fnic trace buffer");
 
+static unsigned int fnic_max_qdepth = FNIC_DFLT_QUEUE_DEPTH;
+module_param(fnic_max_qdepth, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(fnic_max_qdepth, "Queue depth to report for each LUN");
+
 static struct libfc_function_template fnic_transport_template = {
 	.frame_send = fnic_send,
 	.lport_set_port_id = fnic_set_port_id,
···
 	if (!rport || fc_remote_port_chkready(rport))
 		return -ENXIO;
 
-	scsi_activate_tcq(sdev, FNIC_DFLT_QUEUE_DEPTH);
+	scsi_activate_tcq(sdev, fnic_max_qdepth);
 	return 0;
 }
 
···
 
 	host->transportt = fnic_fc_transport;
 
-	err = scsi_init_shared_tag_map(host, FNIC_MAX_IO_REQ);
-	if (err) {
-		shost_printk(KERN_ERR, fnic->lport->host,
-			     "Unable to alloc shared tag map\n");
-		goto err_out_free_hba;
-	}
-
 	/* Setup PCI resources */
 	pci_set_drvdata(pdev, fnic);
 
···
 			     "aborting.\n");
 		goto err_out_dev_close;
 	}
+
+	/* Configure Maximum Outstanding IO reqs*/
+	if (fnic->config.io_throttle_count != FNIC_UCSM_DFLT_THROTTLE_CNT_BLD) {
+		host->can_queue = min_t(u32, FNIC_MAX_IO_REQ,
+					max_t(u32, FNIC_MIN_IO_REQ,
+					fnic->config.io_throttle_count));
+	}
+	fnic->fnic_max_tag_id = host->can_queue;
+
+	err = scsi_init_shared_tag_map(host, fnic->fnic_max_tag_id);
+	if (err) {
+		shost_printk(KERN_ERR, fnic->lport->host,
+			  "Unable to alloc shared tag map\n");
+		goto err_out_dev_close;
+	}
+
 	host->max_lun = fnic->config.luns_per_tgt;
 	host->max_id = FNIC_MAX_FCP_TARGET;
 	host->max_cmd_len = FCOE_MAX_CMD_LEN;

drivers/scsi/fnic/fnic_scsi.c

···
 	fcpio_tag_id_dec(&tag, &id);
 	icmnd_cmpl = &desc->u.icmnd_cmpl;
 
-	if (id >= FNIC_MAX_IO_REQ) {
+	if (id >= fnic->fnic_max_tag_id) {
 		shost_printk(KERN_ERR, fnic->lport->host,
 			"Tag out of range tag %x hdr status = %s\n",
 			     id, fnic_fcpio_status_to_str(hdr_status));
···
 	fcpio_header_dec(&desc->hdr, &type, &hdr_status, &tag);
 	fcpio_tag_id_dec(&tag, &id);
 
-	if ((id & FNIC_TAG_MASK) >= FNIC_MAX_IO_REQ) {
+	if ((id & FNIC_TAG_MASK) >= fnic->fnic_max_tag_id) {
 		shost_printk(KERN_ERR, fnic->lport->host,
 		"Tag out of range tag %x hdr status = %s\n",
 		id, fnic_fcpio_status_to_str(hdr_status));
···
 	spinlock_t *io_lock;
 	unsigned long start_time = 0;
 
-	for (i = 0; i < FNIC_MAX_IO_REQ; i++) {
+	for (i = 0; i < fnic->fnic_max_tag_id; i++) {
 		if (i == exclude_id)
 			continue;
 
···
 	fcpio_tag_id_dec(&desc->hdr.tag, &id);
 	id &= FNIC_TAG_MASK;
 
-	if (id >= FNIC_MAX_IO_REQ)
+	if (id >= fnic->fnic_max_tag_id)
 		return;
 
 	sc = scsi_host_find_tag(fnic->lport->host, id);
···
 	if (fnic->in_remove)
 		return;
 
-	for (tag = 0; tag < FNIC_MAX_IO_REQ; tag++) {
+	for (tag = 0; tag < fnic->fnic_max_tag_id; tag++) {
 		abt_tag = tag;
 		io_lock = fnic_io_lock_tag(fnic, tag);
 		spin_lock_irqsave(io_lock, flags);
···
 	if (fnic->in_remove)
 		return;
 
-	for (tag = 0; tag < FNIC_MAX_IO_REQ; tag++) {
+	for (tag = 0; tag < fnic->fnic_max_tag_id; tag++) {
 		abt_tag = tag;
 		io_lock = fnic_io_lock_tag(fnic, tag);
 		spin_lock_irqsave(io_lock, flags);
···
 	DECLARE_COMPLETION_ONSTACK(tm_done);
 	enum fnic_ioreq_state old_ioreq_state;
 
-	for (tag = 0; tag < FNIC_MAX_IO_REQ; tag++) {
+	for (tag = 0; tag < fnic->fnic_max_tag_id; tag++) {
 		io_lock = fnic_io_lock_tag(fnic, tag);
 		spin_lock_irqsave(io_lock, flags);
 		sc = scsi_host_find_tag(fnic->lport->host, tag);
···
 		lun_dev = lr_sc->device;
 
 	/* walk again to check, if IOs are still pending in fw */
-	for (tag = 0; tag < FNIC_MAX_IO_REQ; tag++) {
+	for (tag = 0; tag < fnic->fnic_max_tag_id; tag++) {
 		sc = scsi_host_find_tag(fnic->lport->host, tag);
 		/*
 		 * ignore this lun reset cmd or cmds that do not belong to

drivers/scsi/fnic/vnic_scsi.h

···
 #define VNIC_FNIC_PLOGI_TIMEOUT_MIN         1000
 #define VNIC_FNIC_PLOGI_TIMEOUT_MAX         255000
 
-#define VNIC_FNIC_IO_THROTTLE_COUNT_MIN     256
-#define VNIC_FNIC_IO_THROTTLE_COUNT_MAX     4096
+#define VNIC_FNIC_IO_THROTTLE_COUNT_MIN     1
+#define VNIC_FNIC_IO_THROTTLE_COUNT_MAX     2048
 
 #define VNIC_FNIC_LINK_DOWN_TIMEOUT_MIN     0
 #define VNIC_FNIC_LINK_DOWN_TIMEOUT_MAX     240000