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 <[email protected]> --- drivers/scsi/fcoe/fcoe_ctlr.c | 28 ++++++++++++++++++++++------ drivers/scsi/libfc/fc_disc.c | 30 +++++++++++++++++++----------- drivers/scsi/libfc/fc_rport.c | 2 ++ 3 files changed, 43 insertions(+), 17 deletions(-) diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c index a569c65..5eacd33 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); } @@ -2638,11 +2644,15 @@ 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 +2663,9 @@ 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 +3002,17 @@ 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); } diff --git a/drivers/scsi/libfc/fc_disc.c b/drivers/scsi/libfc/fc_disc.c index 880a906..351022a 100644 --- a/drivers/scsi/libfc/fc_disc.c +++ b/drivers/scsi/libfc/fc_disc.c @@ -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) - lport->tt.rport_logoff(rdata); - mutex_unlock(&disc->disc_mutex); + rcu_read_lock(); + list_for_each_entry_rcu(rdata, &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(); } /** @@ -289,16 +293,20 @@ 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. */ + mutex_unlock(&disc->disc_mutex); + 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 == disc->disc_id) - lport->tt.rport_login(rdata); - else - lport->tt.rport_logoff(rdata); + 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); } - - mutex_unlock(&disc->disc_mutex); + rcu_read_unlock(); disc->disc_callback(lport, event); mutex_lock(&disc->disc_mutex); } diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c index 91866a5..fa716f5 100644 --- a/drivers/scsi/libfc/fc_rport.c +++ b/drivers/scsi/libfc/fc_rport.c @@ -380,7 +380,9 @@ 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); } -- 1.8.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
