[PATCH 12/17] scsi_dh_alua: parse target device id

Hannes Reinecke
2015-05-04T12:42:41Z

Parse VPD descriptor to figure out the device identification.
As devices might implement several descriptors the order
of preference is:
- NAA IEE Registered Extended
- EUI-64 based 16-byte
- EUI-64 based 12-byte
- NAA IEEE Registered
- NAA IEEE Extended
A SCSI name string descriptor is preferred to all of them
if the identification is longer than 16 bytes.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 125 ++++++++++++++++++++++++++++-
1 file changed, 121 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 98d4a22..2dd9578 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -70,6 +70,9 @@ static DEFINE_SPINLOCK(port_group_lock);
struct alua_port_group {
struct kref kref;
struct list_head node;
+ unsigned char device_id[256];
+ unsigned char device_id_str[256];
+ int device_id_size;
int group_id;
int tpgs;
int state;
@@ -253,17 +256,84 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h)
{
unsigned char *d;
int group_id = -1;
- struct alua_port_group *pg = NULL;
+ char device_id_str[256], *device_id = NULL;
+ int device_id_size, device_id_type = 0;
+ struct alua_port_group *tmp_pg, *pg = NULL;

if (!sdev->vpd_pg83)
return SCSI_DH_DEV_UNSUPP;

/*
* Look for the correct descriptor.
+ * Order of preference for lun descriptor:
+ * - SCSI name string
+ * - NAA IEEE Registered Extended
+ * - EUI-64 based 16-byte
+ * - EUI-64 based 12-byte
+ * - NAA IEEE Registered
+ * - NAA IEEE Extended
+ * as longer descriptors reduce the likelyhood
+ * of identification clashes.
*/
+ memset(device_id_str, 0, 256);
+ device_id_size = 0;
d = sdev->vpd_pg83 + 4;
while (d < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
switch (d[1] & 0xf) {
+ case 0x2:
+ /* EUI-64 */
+ if ((d[1] & 0x30) == 0x00) {
+ if (device_id_size > d[3])
+ break;
+ /* Prefer NAA IEEE Registered Extended */
+ if (device_id_type == 0x3 &&
+ device_id_size == d[3])
+ break;
+ device_id_size = d[3];
+ device_id = d + 4;
+ device_id_type = d[1] & 0xf;
+ switch (device_id_size) {
+ case 8:
+ sprintf(device_id_str,
+ "eui.%8phN", d + 4);
+ break;
+ case 12:
+ sprintf(device_id_str,
+ "eui.%12phN", d + 4);
+ break;
+ case 16:
+ sprintf(device_id_str,
+ "eui.%16phN", d + 4);
+ break;
+ default:
+ device_id_size = 0;
+ break;
+ }
+ }
+ break;
+ case 0x3:
+ /* NAA */
+ if ((d[1] & 0x30) == 0x00) {
+ if (device_id_size > d[3])
+ break;
+ device_id_size = d[3];
+ device_id = d + 4;
+ device_id_type = d[1] & 0xf;
+ switch (device_id_size) {
+ case 8:
+ sprintf(device_id_str,
+ "naa.%8phN", d + 4);
+ break;
+ case 16:
+ sprintf(device_id_str,
+ "naa.%16phN", d + 4);
+ break;
+ default:
+ device_id_size = 0;
+ break;
+ }
+ }
+ break;
case 0x4:
/* Relative target port */
h->rel_port = (d[6] << 8) + d[7];
@@ -272,6 +342,21 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h)
/* Target port group */
group_id = (d[6] << 8) + d[7];
break;
+ case 0x8:
+ /* SCSI name string */
+ if ((d[1] & 0x30) == 0x00) {
+ /* SCSI name */
+ if (device_id_size > d[3])
+ break;
+ device_id_size = d[3];
+ device_id = d + 4;
+ device_id_type = d[1] & 0xf;
+ strncpy(device_id_str, d + 4, 256);
+ if (device_id_size > 255)
+ device_id_size = 255;
+ device_id_str[device_id_size] = '\0';
+ }
+ break;
default:
break;
}
@@ -290,11 +375,35 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h)
h->tpgs = TPGS_MODE_NONE;
return SCSI_DH_DEV_UNSUPP;
}
- sdev_printk(KERN_INFO, sdev,
- "%s: port group %02x rel port %02x\n",
- ALUA_DH_NAME, group_id, h->rel_port);

spin_lock(&port_group_lock);
+ if (device_id_size) {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: device %s port group %02x "
+ "rel port %02x\n", ALUA_DH_NAME,
+ device_id_str, group_id, h->rel_port);
+ list_for_each_entry(tmp_pg, &port_group_list, node) {
+ if (tmp_pg->group_id != group_id)
+ continue;
+ if (tmp_pg->device_id_size != device_id_size)
+ continue;
+ if (memcmp(tmp_pg->device_id, device_id,
+ device_id_size))
+ continue;
+ pg = tmp_pg;
+ break;
+ }
+ } else {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: port group %02x rel port %02x\n",
+ ALUA_DH_NAME, group_id, h->rel_port);
+ }
+ if (pg) {
+ h->pg = pg;
+ kref_get(&pg->kref);
+ spin_unlock(&port_group_lock);
+ return SCSI_DH_OK;
+ }
pg = kzalloc(sizeof(struct alua_port_group), GFP_ATOMIC);
if (!pg) {
sdev_printk(KERN_WARNING, sdev,
@@ -304,6 +413,14 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h)
spin_unlock(&port_group_lock);
return SCSI_DH_DEV_TEMP_BUSY;
}
+ if (device_id_size) {
+ memcpy(pg->device_id, device_id, device_id_size);
+ strncpy(pg->device_id_str, device_id_str, 256);
+ } else {
+ memset(pg->device_id, 0, 256);
+ pg->device_id_str[0] = '\0';
+ }
+ pg->device_id_size = device_id_size;
pg->group_id = group_id;
pg->buff = pg->inq;
pg->bufflen = ALUA_INQUIRY_SIZE;
--
1.8.5.2