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scsi: libfc: Fixup disc_mutex handling

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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>
Acked-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Hannes Reinecke 2016-09-30 11:01:15 +02:00 committed by Martin K. Petersen
parent 4d2095cc42
commit a407c59339
4 changed files with 64 additions and 24 deletions
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39
drivers/scsi/fcoe/fcoe_ctlr.c
View File

@ -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) {
frport = fcoe_ctlr_rport(rdata);
if (!frport->time)
if (!kref_get_unless_zero(&rdata->kref))
continue;
frport = fcoe_ctlr_rport(rdata);
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);
}

28
drivers/scsi/libfc/fc_disc.c
View File

@ -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);
}

9
drivers/scsi/libfc/fc_lport.c
View File

@ -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);

2
drivers/scsi/libfc/fc_rport.c
View File

@ -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);
}