The FC transport class calls scsi_scan_target with the SCAN_WILD_CARD
flag to automatically scan for logical units. zfcp, on the other hand,
only uses the units that are configured via the zfcp sysfs interface.
The main reason for this, is that the adapter behind zfcp supports
adapter sharing without NPIV: The adapter is logged into the SAN once,
and each unit can be used by one Linux system. If one Linux would grab
all LUNs, no other one can use them.
If a unit has the LUN 0, then the SCSI midlayer issue a REPORT LUNS,
checks the found LUN against the max_lun of the hostadapter. zfcp sets
this to 1 to only use its own managed units. If there is a LUN 0 that
is used by zfcp, then the SCSI midlayer produces lots of messages like
"scsi: host 0 channel 0 id 1 lun2 has a LUN larger than allowed by the
host adapter" to indicate the mismatch between the actual LUN and the
max_lun setting. These messages only confuse a user in the case of
zfcp, since there is no error.
To fix this problem, the LLD (zfcp) has to be able to prevent the
automatic scanning from the FC transport class. Attached is a patch
that adds a parameter to fc_remote_port_add(), another approach would
be an additional flag in the FC transport template.
What do others think? If there is an agreement, i will followup with a
new patch.
This can go away, as soon as zfcp does not have to support the
non-NPIV adapter sharing anymore, but this won't happen in the
foreseeable future.
Christof Schmitt
--- linux-2.6.orig/drivers/s390/scsi/zfcp_erp.c 2007-08-14 17:00:07.000000000
+0200
+++ linux-2.6/drivers/s390/scsi/zfcp_erp.c 2007-08-20 12:54:03.000000000
+0200
@@ -3175,7 +3175,7 @@ zfcp_erp_action_cleanup(int action, stru
ids.port_id = port->d_id;
ids.roles = FC_RPORT_ROLE_FCP_TARGET;
port->rport =
- fc_remote_port_add(adapter->scsi_host, 0, &ids);
+ fc_remote_port_add(adapter->scsi_host, 0, &ids,
0);
if (!port->rport)
ZFCP_LOG_NORMAL("failed registration of rport"
"(adapter %s, wwpn=0x%016Lx)\n",
--- linux-2.6.orig/drivers/scsi/scsi_transport_fc.c 2007-08-14
17:00:07.000000000 +0200
+++ linux-2.6/drivers/scsi/scsi_transport_fc.c 2007-08-20 12:56:15.000000000
+0200
@@ -2360,7 +2360,7 @@ fc_rport_final_delete(struct work_struct
**/
static struct fc_rport *
fc_rport_create(struct Scsi_Host *shost, int channel,
- struct fc_rport_identifiers *ids)
+ struct fc_rport_identifiers *ids, int scan_target)
{
struct fc_host_attrs *fc_host = shost_to_fc_host(shost);
struct fc_internal *fci = to_fc_internal(shost->transportt);
@@ -2424,6 +2424,9 @@ fc_rport_create(struct Scsi_Host *shost,
transport_add_device(dev);
transport_configure_device(dev);
+ if (scan_target)
+ rport->flags |= FC_RPORT_SCAN_TARGET;
+
if (rport->roles & FC_PORT_ROLE_FCP_TARGET) {
/* initiate a scan of the target */
rport->flags |= FC_RPORT_SCAN_PENDING;
@@ -2484,7 +2487,7 @@ delete_rport:
**/
struct fc_rport *
fc_remote_port_add(struct Scsi_Host *shost, int channel,
- struct fc_rport_identifiers *ids)
+ struct fc_rport_identifiers *ids, int scan_target)
{
struct fc_internal *fci = to_fc_internal(shost->transportt);
struct fc_host_attrs *fc_host = shost_to_fc_host(shost);
@@ -2574,6 +2577,10 @@ fc_remote_port_add(struct Scsi_Host *sho
spin_lock_irqsave(shost->host_lock, flags);
rport->flags &= ~FC_RPORT_DEVLOSS_PENDING;
+ if (scan_target)
+ rport->flags |= FC_RPORT_SCAN_TARGET;
+ else
+ rport->flags &= ~FC_RPORT_SCAN_TARGET;
/* if target, initiate a scan */
if (rport->scsi_target_id != -1) {
@@ -2657,7 +2664,7 @@ fc_remote_port_add(struct Scsi_Host *sho
spin_unlock_irqrestore(shost->host_lock, flags);
/* No consistent binding found - create new remote port entry */
- rport = fc_rport_create(shost, channel, ids);
+ rport = fc_rport_create(shost, channel, ids, scan_target);
return rport;
}
@@ -2991,7 +2998,8 @@ fc_scsi_scan_rport(struct work_struct *w
unsigned long flags;
if ((rport->port_state == FC_PORTSTATE_ONLINE) &&
- (rport->roles & FC_PORT_ROLE_FCP_TARGET)) {
+ (rport->roles & FC_PORT_ROLE_FCP_TARGET) &&
+ (rport->flags & FC_RPORT_SCAN_TARGET)) {
scsi_scan_target(&rport->dev, rport->channel,
rport->scsi_target_id, SCAN_WILD_CARD, 1);
}
--- linux-2.6.orig/include/scsi/scsi_transport_fc.h 2007-08-14
17:00:09.000000000 +0200
+++ linux-2.6/include/scsi/scsi_transport_fc.h 2007-08-20 12:54:03.000000000
+0200
@@ -338,6 +338,7 @@ struct fc_rport { /* aka fc_starget_attr
/* bit field values for struct fc_rport "flags" field: */
#define FC_RPORT_DEVLOSS_PENDING 0x01
#define FC_RPORT_SCAN_PENDING 0x02
+#define FC_RPORT_SCAN_TARGET 0x04
#define dev_to_rport(d) \
container_of(d, struct fc_rport, dev)
@@ -713,7 +714,8 @@ struct scsi_transport_template *fc_attac
void fc_release_transport(struct scsi_transport_template *);
void fc_remove_host(struct Scsi_Host *);
struct fc_rport *fc_remote_port_add(struct Scsi_Host *shost,
- int channel, struct fc_rport_identifiers *ids);
+ int channel, struct fc_rport_identifiers *ids,
+ int scan_target);
void fc_remote_port_delete(struct fc_rport *rport);
void fc_remote_port_rolechg(struct fc_rport *rport, u32 roles);
int scsi_is_fc_rport(const struct device *);
-
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