IB/srp: Maintain a single connection per I_T nexus
An SRP target is required to maintain a single connection between
initiator and target. This means that if the 'add_target' attribute
is used to create a second connection to a target, the first
connection will be logged out and that the SCSI error handler will
kick in. The SCSI error handler will cause the SRP initiator to
reconnect, which will cause I/O over the second connection to fail.
Avoid such ping-pong behavior by disabling relogins.
If reconnecting manually is necessary, that is possible by deleting
and recreating an rport via sysfs.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Sebastian Riemer <sebastian.riemer@profitbricks.com>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 1f33101..830ef00 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -542,11 +542,11 @@
WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);
+ srp_remove_target(target);
+
spin_lock(&target->srp_host->target_lock);
list_del(&target->list);
spin_unlock(&target->srp_host->target_lock);
-
- srp_remove_target(target);
}
static void srp_rport_delete(struct srp_rport *rport)
@@ -2009,6 +2009,36 @@
.dev_release = srp_release_dev
};
+/**
+ * srp_conn_unique() - check whether the connection to a target is unique
+ */
+static bool srp_conn_unique(struct srp_host *host,
+ struct srp_target_port *target)
+{
+ struct srp_target_port *t;
+ bool ret = false;
+
+ if (target->state == SRP_TARGET_REMOVED)
+ goto out;
+
+ ret = true;
+
+ spin_lock(&host->target_lock);
+ list_for_each_entry(t, &host->target_list, list) {
+ if (t != target &&
+ target->id_ext == t->id_ext &&
+ target->ioc_guid == t->ioc_guid &&
+ target->initiator_ext == t->initiator_ext) {
+ ret = false;
+ break;
+ }
+ }
+ spin_unlock(&host->target_lock);
+
+out:
+ return ret;
+}
+
/*
* Target ports are added by writing
*
@@ -2265,6 +2295,16 @@
if (ret)
goto err;
+ if (!srp_conn_unique(target->srp_host, target)) {
+ shost_printk(KERN_INFO, target->scsi_host,
+ PFX "Already connected to target port with id_ext=%016llx;ioc_guid=%016llx;initiator_ext=%016llx\n",
+ be64_to_cpu(target->id_ext),
+ be64_to_cpu(target->ioc_guid),
+ be64_to_cpu(target->initiator_ext));
+ ret = -EEXIST;
+ goto err;
+ }
+
if (!host->srp_dev->fmr_pool && !target->allow_ext_sg &&
target->cmd_sg_cnt < target->sg_tablesize) {
pr_warn("No FMR pool and no external indirect descriptors, limiting sg_tablesize to cmd_sg_cnt\n");