[SCSI] libosd: osd_dev_info: Unique Identification of an OSD device

Define an osd_dev_info structure that Uniquely identifies an OSD
device lun on the network. The identification is built from unique
target attributes and is the same for all network/SAN machines.

osduld_info_lookup() - NEW
    New API that will lookup an osd_dev by its osd_dev_info.
    This is used by pNFS-objects for cross network global device
    identification. And by exofs multy-device support, the device
    info is specified in the on-disk exofs device table.

osduld_device_info() - NEW
    Given an osd_dev handle returns its associated osd_dev_info.
    The ULD fetches this information at startup and hangs it on
    each OSD device. (This is a fast operation that can be called
    at any condition)

osduld_device_same() - NEW
    With a given osd_dev at one hand and an osd_dev_info
    at another, we would like to know if they are the same
    device.
    Two osd_dev handles can be checked by:
        osduld_device_same(od1, osduld_device_info(od2));

osd_auto_detect_ver() - REVISED
    Now returns an osd_dev_info structure. Is only called once
    by ULD as before. See added comments for how to use.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 20 insertions, 6 deletions

diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 7a117c1..60b7ca1 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -73,7 +73,8 @@ static const char *_osd_ver_desc(struct osd_request *or)
 
 #define ATTR_DEF_RI(id, len) ATTR_DEF(OSD_APAGE_ROOT_INFORMATION, id, len)
 
-static int _osd_print_system_info(struct osd_dev *od, void *caps)
+static int _osd_get_print_system_info(struct osd_dev *od,
+	void *caps, struct osd_dev_info *odi)
 {
 	struct osd_request *or;
 	struct osd_attr get_attrs[] = {
@@ -137,8 +138,12 @@ static int _osd_print_system_info(struct osd_dev *od, void *caps)
 	OSD_INFO("PRODUCT_SERIAL_NUMBER  [%s]\n",
 		(char *)pFirst);
 
-	pFirst = get_attrs[a].val_ptr;
-	OSD_INFO("OSD_NAME               [%s]\n", (char *)pFirst);
+	odi->osdname_len = get_attrs[a].len;
+	/* Avoid NULL for memcmp optimization 0-length is good enough */
+	odi->osdname = kzalloc(odi->osdname_len + 1, GFP_KERNEL);
+	if (odi->osdname_len)
+		memcpy(odi->osdname, get_attrs[a].val_ptr, odi->osdname_len);
+	OSD_INFO("OSD_NAME               [%s]\n", odi->osdname);
 	a++;
 
 	pFirst = get_attrs[a++].val_ptr;
@@ -171,6 +176,14 @@ static int _osd_print_system_info(struct osd_dev *od, void *caps)
 				   sid_dump, sizeof(sid_dump), true);
 		OSD_INFO("OSD_SYSTEM_ID(%d)\n"
 			 "        [%s]\n", len, sid_dump);
+
+		if (unlikely(len > sizeof(odi->systemid))) {
+			OSD_ERR("OSD Target error: OSD_SYSTEM_ID too long(%d). "
+				"device idetification might not work\n", len);
+			len = sizeof(odi->systemid);
+		}
+		odi->systemid_len = len;
+		memcpy(odi->systemid, get_attrs[a].val_ptr, len);
 		a++;
 	}
 out:
@@ -178,16 +191,17 @@ out:
 	return ret;
 }
 
-int osd_auto_detect_ver(struct osd_dev *od, void *caps)
+int osd_auto_detect_ver(struct osd_dev *od,
+	void *caps, struct osd_dev_info *odi)
 {
 	int ret;
 
 	/* Auto-detect the osd version */
-	ret = _osd_print_system_info(od, caps);
+	ret = _osd_get_print_system_info(od, caps, odi);
 	if (ret) {
 		osd_dev_set_ver(od, OSD_VER1);
 		OSD_DEBUG("converting to OSD1\n");
-		ret = _osd_print_system_info(od, caps);
+		ret = _osd_get_print_system_info(od, caps, odi);
 	}
 
 	return ret;