From: Hannes Reinecke <hare@suse.de>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: James Bottomley <james.bottomley@hansenpartnership.com>,
Christoph Hellwig <hch@lst.de>,
Johannes Thumshirn <jth@kernel.org>,
linux-scsi@vger.kernel.org, Mike Snitzer <snitzer@redhat.com>,
Martin Wilck <martin.wilck@suse.com>,
Hannes Reinecke <hare@suse.de>, Hannes Reinecke <hare@suse.com>
Subject: [PATCH 11/30] libfc: Fixup disc_mutex handling
Date: Fri, 26 Aug 2016 14:01:34 +0200 [thread overview]
Message-ID: <1472212913-39810-12-git-send-email-hare@suse.de> (raw)
In-Reply-To: <1472212913-39810-1-git-send-email-hare@suse.de>
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@suse.com>
---
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
next prev parent reply other threads:[~2016-08-26 12:02 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-26 12:01 [PATCH 00/30] FCoE VN2VN fixes Hannes Reinecke
2016-08-26 12:01 ` [PATCH 01/30] libfc: Revisit kref handling Hannes Reinecke
2016-08-26 13:37 ` Johannes Thumshirn
2016-08-26 12:01 ` [PATCH 02/30] libfc: additional debugging messages Hannes Reinecke
2016-08-26 12:01 ` [PATCH 03/30] libfc: spurious I/O error under high load Hannes Reinecke
2016-08-26 12:01 ` [PATCH 04/30] libfc: Do not login if the port is already started Hannes Reinecke
2016-08-26 12:01 ` [PATCH 05/30] libfc: use configured lport R_A_TOV when sending Hannes Reinecke
2016-08-26 12:01 ` [PATCH 06/30] libfc: use configured e_d_tov for remote port state Hannes Reinecke
2016-08-26 12:01 ` [PATCH 07/30] libfc: do not overwrite DID_TIME_OUT status Hannes Reinecke
2016-08-26 12:01 ` [PATCH 08/30] libfc: use error code for fc_rport_error() Hannes Reinecke
2016-08-26 12:01 ` [PATCH 09/30] libfc: Send LS_RJT responses on frame allocation Hannes Reinecke
2016-08-26 12:01 ` [PATCH 10/30] libfc: don't advance state machine for incoming FLOGI Hannes Reinecke
2016-08-26 12:01 ` Hannes Reinecke [this message]
2016-08-26 12:01 ` [PATCH 12/30] libfc: Do not drop down to FLOGI for fc_rport_login() Hannes Reinecke
2016-08-26 12:01 ` [PATCH 13/30] libfc: Implement RTV responder Hannes Reinecke
2016-08-26 12:01 ` [PATCH 14/30] libfc: Rework PRLI handling Hannes Reinecke
2016-08-26 12:01 ` [PATCH 15/30] libfc: Return LS_RJT_BUSY for PRLI in status PLOGI Hannes Reinecke
2016-08-26 12:01 ` [PATCH 16/30] libfc: Clarify ramp-down messages Hannes Reinecke
2016-08-26 12:01 ` [PATCH 17/30] libfc: sanitize E_D_TOV and R_A_TOV setting Hannes Reinecke
2016-08-26 12:01 ` [PATCH 18/30] libfc: safeguard against invalid exchange index Hannes Reinecke
2016-08-26 12:01 ` [PATCH 19/30] libfc: quarantine timed out xids Hannes Reinecke
2016-08-26 12:01 ` [PATCH 20/30] libfc: don't fail sequence abort for completed Hannes Reinecke
2016-08-26 12:01 ` [PATCH 21/30] libfc: Do not drop out-of-order frames Hannes Reinecke
2016-08-26 12:01 ` [PATCH 22/30] libfc: reset timeout on queue full Hannes Reinecke
2016-08-26 12:01 ` [PATCH 23/30] libfc: wait for E_D_TOV when out-of-order sequence is received Hannes Reinecke
2016-08-26 12:01 ` [PATCH 24/30] fcoe: Use kfree_skb() instead of kfree() Hannes Reinecke
2016-08-26 12:01 ` [PATCH 25/30] fcoe: set default TC priority Hannes Reinecke
2016-08-26 12:01 ` [PATCH 26/30] fcoe: inhibit writing invalid values into the 'enabled' Hannes Reinecke
2016-08-26 12:01 ` [PATCH 27/30] fcoe: correct sending FIP VLAN packets on VLAN 0 Hannes Reinecke
2016-08-26 12:01 ` [PATCH 28/30] fcoe: FIP debugging Hannes Reinecke
2016-08-26 12:01 ` [PATCH 29/30] fcoe: filter out frames from invalid vlans Hannes Reinecke
2016-08-26 12:01 ` [PATCH 30/30] fcoe: make R_A_TOV and E_D_TOV configurable Hannes Reinecke
2016-08-26 13:48 ` [PATCH 00/30] FCoE VN2VN fixes Johannes Thumshirn
2016-08-31 2:46 ` Martin K. Petersen
2016-08-31 7:25 ` Johannes Thumshirn
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