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Commit 96fc248a authored by Bart Van Assche's avatar Bart Van Assche Committed by Roland Dreier
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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: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarSebastian Riemer <sebastian.riemer@profitbricks.com>
Acked-by: default avatarDavid Dillow <dillowda@ornl.gov>
Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
parent 99e1c139

drivers/infiniband/ulp/srp/ib_srp.c

+42 −2
Original line number Original line Diff line number Diff line
@@ -542,11 +542,11 @@ static void srp_remove_work(struct work_struct *work) 




	WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);

	WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);





	srp_remove_target(target);



	spin_lock(&target->srp_host->target_lock);

	spin_lock(&target->srp_host->target_lock);

	list_del(&target->list);

	list_del(&target->list);

	spin_unlock(&target->srp_host->target_lock);

	spin_unlock(&target->srp_host->target_lock);



	srp_remove_target(target);

}

}





static void srp_rport_delete(struct srp_rport *rport)

static void srp_rport_delete(struct srp_rport *rport)
@@ -2009,6 +2009,36 @@ static struct class srp_class = { 
	.dev_release = srp_release_dev

	.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

 * Target ports are added by writing

 *

 *
@@ -2265,6 +2295,16 @@ static ssize_t srp_create_target(struct device *dev, 
	if (ret)

	if (ret)

		goto err;

		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 &&

	if (!host->srp_dev->fmr_pool && !target->allow_ext_sg &&

				target->cmd_sg_cnt < target->sg_tablesize) {

				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");

		pr_warn("No FMR pool and no external indirect descriptors, limiting sg_tablesize to cmd_sg_cnt\n");