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Commit a407c593 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Martin K. Petersen
Browse files

scsi: libfc: Fixup disc_mutex handling 



The list of attached 'rdata' remote port structures is RCU
protected, so there is no need to take the 'disc_mutex' when
traversing it.
Rather we should be using rcu_read_lock() and kref_get_unless_zero()
to validate the entries.
We need, however, take the disc_mutex when deleting an entry;
otherwise we risk clashes with list_add.

Signed-off-by: default avatarHannes Reinecke <hare@suse.com>
Acked-by: default avatarJohannes Thumshirn <jth@kernel.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 4d2095cc

drivers/scsi/fcoe/fcoe_ctlr.c

+29 −8
Original line number Diff line number Diff line
@@ -2145,9 +2145,15 @@ static void fcoe_ctlr_disc_stop_locked(struct fc_lport *lport) 
{

	struct fc_rport_priv *rdata;



	mutex_lock(&lport->disc.disc_mutex);

	list_for_each_entry_rcu(rdata, &lport->disc.rports, peers)

	rcu_read_lock();

	list_for_each_entry_rcu(rdata, &lport->disc.rports, peers) {

		if (kref_get_unless_zero(&rdata->kref)) {

			lport->tt.rport_logoff(rdata);

			kref_put(&rdata->kref, lport->tt.rport_destroy);

		}

	}

	rcu_read_unlock();

	mutex_lock(&lport->disc.disc_mutex);

	lport->disc.disc_callback = NULL;

	mutex_unlock(&lport->disc.disc_mutex);

}
@@ -2472,17 +2478,22 @@ static void fcoe_ctlr_vn_add(struct fcoe_ctlr *fip, struct fc_rport_priv *new) 
		mutex_unlock(&lport->disc.disc_mutex);

		return;

	}

	mutex_lock(&rdata->rp_mutex);

	mutex_unlock(&lport->disc.disc_mutex);



	rdata->ops = &fcoe_ctlr_vn_rport_ops;

	rdata->disc_id = lport->disc.disc_id;



	ids = &rdata->ids;

	if ((ids->port_name != -1 && ids->port_name != new->ids.port_name) ||

	    (ids->node_name != -1 && ids->node_name != new->ids.node_name))

	    (ids->node_name != -1 && ids->node_name != new->ids.node_name)) {

		mutex_unlock(&rdata->rp_mutex);

		lport->tt.rport_logoff(rdata);

		mutex_lock(&rdata->rp_mutex);

	}

	ids->port_name = new->ids.port_name;

	ids->node_name = new->ids.node_name;

	mutex_unlock(&lport->disc.disc_mutex);

	mutex_unlock(&rdata->rp_mutex);



	frport = fcoe_ctlr_rport(rdata);

	LIBFCOE_FIP_DBG(fip, "vn_add rport %6.6x %s\n",
@@ -2638,11 +2649,15 @@ static unsigned long fcoe_ctlr_vn_age(struct fcoe_ctlr *fip) 
	unsigned long deadline;



	next_time = jiffies + msecs_to_jiffies(FIP_VN_BEACON_INT * 10);

	mutex_lock(&lport->disc.disc_mutex);

	rcu_read_lock();

	list_for_each_entry_rcu(rdata, &lport->disc.rports, peers) {

		if (!kref_get_unless_zero(&rdata->kref))

			continue;

		frport = fcoe_ctlr_rport(rdata);

		if (!frport->time)

		if (!frport->time) {

			kref_put(&rdata->kref, lport->tt.rport_destroy);

			continue;

		}

		deadline = frport->time +

			   msecs_to_jiffies(FIP_VN_BEACON_INT * 25 / 10);

		if (time_after_eq(jiffies, deadline)) {
@@ -2653,8 +2668,9 @@ static unsigned long fcoe_ctlr_vn_age(struct fcoe_ctlr *fip) 
			lport->tt.rport_logoff(rdata);

		} else if (time_before(deadline, next_time))

			next_time = deadline;

		kref_put(&rdata->kref, lport->tt.rport_destroy);

	}

	mutex_unlock(&lport->disc.disc_mutex);

	rcu_read_unlock();

	return next_time;

}
@@ -2991,12 +3007,17 @@ static void fcoe_ctlr_vn_disc(struct fcoe_ctlr *fip) 
	mutex_lock(&disc->disc_mutex);

	callback = disc->pending ? disc->disc_callback : NULL;

	disc->pending = 0;

	mutex_unlock(&disc->disc_mutex);

	rcu_read_lock();

	list_for_each_entry_rcu(rdata, &disc->rports, peers) {

		if (!kref_get_unless_zero(&rdata->kref))

			continue;

		frport = fcoe_ctlr_rport(rdata);

		if (frport->time)

			lport->tt.rport_login(rdata);

		kref_put(&rdata->kref, lport->tt.rport_destroy);

	}

	mutex_unlock(&disc->disc_mutex);

	rcu_read_unlock();

	if (callback)

		callback(lport, DISC_EV_SUCCESS);

}

drivers/scsi/libfc/fc_disc.c

+25 −13
Original line number Diff line number Diff line
@@ -68,10 +68,14 @@ static void fc_disc_stop_rports(struct fc_disc *disc) 


	lport = fc_disc_lport(disc);



	mutex_lock(&disc->disc_mutex);

	list_for_each_entry_rcu(rdata, &disc->rports, peers)

	rcu_read_lock();

	list_for_each_entry_rcu(rdata, &disc->rports, peers) {

		if (kref_get_unless_zero(&rdata->kref)) {

			lport->tt.rport_logoff(rdata);

	mutex_unlock(&disc->disc_mutex);

			kref_put(&rdata->kref, lport->tt.rport_destroy);

		}

	}

	rcu_read_unlock();

}



/**
@@ -289,15 +293,19 @@ static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event) 
	 * Skip ports which were never discovered.  These are the dNS port

	 * and ports which were created by PLOGI.

	 */

	rcu_read_lock();

	list_for_each_entry_rcu(rdata, &disc->rports, peers) {

		if (!rdata->disc_id)

		if (!kref_get_unless_zero(&rdata->kref))

			continue;

		if (rdata->disc_id) {

			if (rdata->disc_id == disc->disc_id)

				lport->tt.rport_login(rdata);

			else

				lport->tt.rport_logoff(rdata);

		}



		kref_put(&rdata->kref, lport->tt.rport_destroy);

	}

	rcu_read_unlock();

	mutex_unlock(&disc->disc_mutex);

	disc->disc_callback(lport, event);

	mutex_lock(&disc->disc_mutex);
@@ -592,7 +600,6 @@ static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp, 
	lport = rdata->local_port;

	disc = &lport->disc;



	mutex_lock(&disc->disc_mutex);

	if (PTR_ERR(fp) == -FC_EX_CLOSED)

		goto out;

	if (IS_ERR(fp))
@@ -607,16 +614,19 @@ static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp, 
			goto redisc;

		pn = (struct fc_ns_gid_pn *)(cp + 1);

		port_name = get_unaligned_be64(&pn->fn_wwpn);

		mutex_lock(&rdata->rp_mutex);

		if (rdata->ids.port_name == -1)

			rdata->ids.port_name = port_name;

		else if (rdata->ids.port_name != port_name) {

			FC_DISC_DBG(disc, "GPN_ID accepted.  WWPN changed. "

				    "Port-id %6.6x wwpn %16.16llx\n",

				    rdata->ids.port_id, port_name);

			mutex_unlock(&rdata->rp_mutex);

			lport->tt.rport_logoff(rdata);



			mutex_lock(&lport->disc.disc_mutex);

			new_rdata = lport->tt.rport_create(lport,

							   rdata->ids.port_id);

			mutex_unlock(&lport->disc.disc_mutex);

			if (new_rdata) {

				new_rdata->disc_id = disc->disc_id;

				lport->tt.rport_login(new_rdata);
@@ -624,6 +634,7 @@ static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp, 
			goto out;

		}

		rdata->disc_id = disc->disc_id;

		mutex_unlock(&rdata->rp_mutex);

		lport->tt.rport_login(rdata);

	} else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {

		FC_DISC_DBG(disc, "GPN_ID rejected reason %x exp %x\n",
@@ -633,10 +644,11 @@ static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp, 
		FC_DISC_DBG(disc, "GPN_ID unexpected response code %x\n",

			    ntohs(cp->ct_cmd));

redisc:

		mutex_lock(&disc->disc_mutex);

		fc_disc_restart(disc);

		mutex_unlock(&disc->disc_mutex);

	}

out:

	mutex_unlock(&disc->disc_mutex);

	kref_put(&rdata->kref, lport->tt.rport_destroy);

}

drivers/scsi/libfc/fc_lport.c

+7 −2
Original line number Diff line number Diff line
@@ -237,16 +237,19 @@ static const char *fc_lport_state(struct fc_lport *lport) 
 * @remote_fid:	 The FID of the ptp rport

 * @remote_wwpn: The WWPN of the ptp rport

 * @remote_wwnn: The WWNN of the ptp rport

 *

 * Locking Note: The lport lock is expected to be held before calling

 * this routine.

 */

static void fc_lport_ptp_setup(struct fc_lport *lport,

			       u32 remote_fid, u64 remote_wwpn,

			       u64 remote_wwnn)

{

	mutex_lock(&lport->disc.disc_mutex);

	if (lport->ptp_rdata) {

		lport->tt.rport_logoff(lport->ptp_rdata);

		kref_put(&lport->ptp_rdata->kref, lport->tt.rport_destroy);

	}

	mutex_lock(&lport->disc.disc_mutex);

	lport->ptp_rdata = lport->tt.rport_create(lport, remote_fid);

	kref_get(&lport->ptp_rdata->kref);

	lport->ptp_rdata->ids.port_name = remote_wwpn;
@@ -1007,8 +1010,10 @@ EXPORT_SYMBOL(fc_lport_reset); 
 */

static void fc_lport_reset_locked(struct fc_lport *lport)

{

	if (lport->dns_rdata)

	if (lport->dns_rdata) {

		lport->tt.rport_logoff(lport->dns_rdata);

		lport->dns_rdata = NULL;

	}



	if (lport->ptp_rdata) {

		lport->tt.rport_logoff(lport->ptp_rdata);

drivers/scsi/libfc/fc_rport.c

+2 −0
Original line number Diff line number Diff line
@@ -378,7 +378,9 @@ static void fc_rport_work(struct work_struct *work) 
				mutex_unlock(&rdata->rp_mutex);

			} else {

				FC_RPORT_DBG(rdata, "work delete\n");

				mutex_lock(&lport->disc.disc_mutex);

				list_del_rcu(&rdata->peers);

				mutex_unlock(&lport->disc.disc_mutex);

				mutex_unlock(&rdata->rp_mutex);

				kref_put(&rdata->kref, lport->tt.rport_destroy);

			}