From a407c593398c886db4fa1fc5c6fec55e61187a09 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Fri, 30 Sep 2016 11:01:15 +0200 Subject: 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: Hannes Reinecke Acked-by: Johannes Thumshirn Signed-off-by: Martin K. Petersen --- drivers/scsi/fcoe/fcoe_ctlr.c | 37 +++++++++++++++++++++++++++++-------- 1 file changed, 29 insertions(+), 8 deletions(-) (limited to 'drivers/scsi/fcoe') diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c index dcf36537a767..9bba58191b3d 100644 --- a/drivers/scsi/fcoe/fcoe_ctlr.c +++ b/drivers/scsi/fcoe/fcoe_ctlr.c @@ -2145,9 +2145,15 @@ static void fcoe_ctlr_disc_stop_locked(struct fc_lport *lport) { struct fc_rport_priv *rdata; + 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); - list_for_each_entry_rcu(rdata, &lport->disc.rports, peers) - lport->tt.rport_logoff(rdata); 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); } -- cgit v1.2.1