[SCSI] add supported_mode and active_mode attributes to the host

This adds supported_mode and active_mode attributes to
/sys/class/sys_host/hostX/ for specifying the mode that a lld supports
and the currently activated mode. The output format is similar to fc
rport roles:

luce:/sys/class/scsi_host/host0$ cat supported_mode
Initiator
luce:/sys/class/scsi_host/host0$ cat active_mode
Initiator

The mode values uses bitmap since we would support dual-mode llds in
the future like this:

luce:/sys/class/scsi_host/host0$ cat supported_mode
Initiator, Target

The supported_mode attribute looks at a scsi_host_template and the
active_mode attribute looks at a scsi_host. We would add a hook to a
scsi_host_template to change the active_mode attribute
dynamically. But now there is no hook since no lld supports that
feature.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/hosts.c

@@ -342,6 +342,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 	shost->use_clustering = sht->use_clustering;
 	shost->ordered_tag = sht->ordered_tag;
+	shost->active_mode = sht->supported_mode;
 
 	if (sht->max_host_blocked)
 		shost->max_host_blocked = sht->max_host_blocked;

drivers/scsi/scsi_sysfs.c

@@ -190,6 +190,46 @@ show_shost_state(struct class_device *class_dev, char *buf)
 
 static CLASS_DEVICE_ATTR(state, S_IRUGO | S_IWUSR, show_shost_state, store_shost_state);
 
+static ssize_t
+show_shost_mode(unsigned int mode, char *buf)
+{
+	ssize_t len = 0;
+
+	if (mode & MODE_INITIATOR)
+		len = sprintf(buf, "%s", "Initiator");
+
+	if (mode & MODE_TARGET)
+		len += sprintf(buf + len, "%s%s", len ? ", " : "", "Target");
+
+	len += sprintf(buf + len, "\n");
+
+	return len;
+}
+
+static ssize_t show_shost_supported_mode(struct class_device *class_dev, char *buf)
+{
+	struct Scsi_Host *shost = class_to_shost(class_dev);
+
+	if (shost->hostt->supported_mode == MODE_UNKNOWN)
+		return snprintf(buf, 20, "unknown\n");
+	else
+		return show_shost_mode(shost->hostt->supported_mode, buf);
+}
+
+static CLASS_DEVICE_ATTR(supported_mode, S_IRUGO | S_IWUSR, show_shost_supported_mode, NULL);
+
+static ssize_t show_shost_active_mode(struct class_device *class_dev, char *buf)
+{
+	struct Scsi_Host *shost = class_to_shost(class_dev);
+
+	if (shost->active_mode == MODE_UNKNOWN)
+		return snprintf(buf, 20, "unknown\n");
+	else
+		return show_shost_mode(shost->active_mode, buf);
+}
+
+static CLASS_DEVICE_ATTR(active_mode, S_IRUGO | S_IWUSR, show_shost_active_mode, NULL);
+
 shost_rd_attr(unique_id, "%u\n");
 shost_rd_attr(host_busy, "%hu\n");
 shost_rd_attr(cmd_per_lun, "%hd\n");
@@ -208,6 +248,8 @@ static struct class_device_attribute *scsi_sysfs_shost_attrs[] = {
 	&class_device_attr_proc_name,
 	&class_device_attr_scan,
 	&class_device_attr_state,
+	&class_device_attr_supported_mode,
+	&class_device_attr_active_mode,
 	NULL
 };
 

include/scsi/scsi_host.h

@@ -32,6 +32,9 @@ struct blk_queue_tags;
 #define SG_NONE 0
 #define SG_ALL 0xff
 
+#define MODE_UNKNOWN 0x00
+#define MODE_INITIATOR 0x01
+#define MODE_TARGET 0x02
 
 #define DISABLE_CLUSTERING 0
 #define ENABLE_CLUSTERING 1
@@ -404,6 +407,11 @@ struct scsi_host_template {
 	 */
 	unsigned char present;
 
+	/*
+	 * This specifies the mode that a LLD supports.
+	 */
+	unsigned supported_mode:2;
+
 	/*
 	 * true if this host adapter uses unchecked DMA onto an ISA bus.
 	 */
@@ -574,6 +582,7 @@ struct Scsi_Host {
 	 */
 	unsigned long cmd_serial_number, cmd_pid; 
 	
+	unsigned active_mode:2;
 	unsigned unchecked_isa_dma:1;
 	unsigned use_clustering:1;
 	unsigned use_blk_tcq:1;