[SCSI] libfc: convert rport lookup to be RCU safe
To allow LLD to do lookups on rports without grabbing a mutex,
make them RCU-safe. The caller of lport->tt.rport_lookup will
have the choice of holding disc_mutex or the rcu_read_lock().
Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
index 363cde3..6b56973 100644
--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c
@@ -95,13 +95,15 @@
* fc_rport_lookup() - Lookup a remote port by port_id
* @lport: The local port to lookup the remote port on
* @port_id: The remote port ID to look up
+ *
+ * The caller must hold either disc_mutex or rcu_read_lock().
*/
static struct fc_rport_priv *fc_rport_lookup(const struct fc_lport *lport,
u32 port_id)
{
struct fc_rport_priv *rdata;
- list_for_each_entry(rdata, &lport->disc.rports, peers)
+ list_for_each_entry_rcu(rdata, &lport->disc.rports, peers)
if (rdata->ids.port_id == port_id)
return rdata;
return NULL;
@@ -146,11 +148,23 @@
INIT_DELAYED_WORK(&rdata->retry_work, fc_rport_timeout);
INIT_WORK(&rdata->event_work, fc_rport_work);
if (port_id != FC_FID_DIR_SERV)
- list_add(&rdata->peers, &lport->disc.rports);
+ list_add_rcu(&rdata->peers, &lport->disc.rports);
return rdata;
}
/**
+ * fc_rport_free_rcu() - Free a remote port
+ * @rcu: The rcu_head structure inside the remote port
+ */
+static void fc_rport_free_rcu(struct rcu_head *rcu)
+{
+ struct fc_rport_priv *rdata;
+
+ rdata = container_of(rcu, struct fc_rport_priv, rcu);
+ kfree(rdata);
+}
+
+/**
* fc_rport_destroy() - Free a remote port after last reference is released
* @kref: The remote port's kref
*/
@@ -159,7 +173,7 @@
struct fc_rport_priv *rdata;
rdata = container_of(kref, struct fc_rport_priv, kref);
- kfree(rdata);
+ call_rcu(&rdata->rcu, fc_rport_free_rcu);
}
/**
@@ -334,7 +348,7 @@
mutex_unlock(&rdata->rp_mutex);
} else {
FC_RPORT_DBG(rdata, "work delete\n");
- list_del(&rdata->peers);
+ list_del_rcu(&rdata->peers);
mutex_unlock(&rdata->rp_mutex);
kref_put(&rdata->kref, lport->tt.rport_destroy);
}