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 <hare@xxxxxxxx>
---
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
--
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