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[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>
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@ -63,12 +63,12 @@ static void fc_disc_restart(struct fc_disc *);
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void fc_disc_stop_rports(struct fc_disc *disc)
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{
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struct fc_lport *lport;
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struct fc_rport_priv *rdata, *next;
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struct fc_rport_priv *rdata;
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lport = disc->lport;
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mutex_lock(&disc->disc_mutex);
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list_for_each_entry_safe(rdata, next, &disc->rports, peers)
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list_for_each_entry_rcu(rdata, &disc->rports, peers)
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lport->tt.rport_logoff(rdata);
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mutex_unlock(&disc->disc_mutex);
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}
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@ -292,7 +292,7 @@ static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event)
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* Skip ports which were never discovered. These are the dNS port
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* and ports which were created by PLOGI.
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*/
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list_for_each_entry(rdata, &disc->rports, peers) {
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list_for_each_entry_rcu(rdata, &disc->rports, peers) {
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if (!rdata->disc_id)
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continue;
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if (rdata->disc_id == disc->disc_id)
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@ -95,13 +95,15 @@ static const char *fc_rport_state_names[] = {
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* fc_rport_lookup() - Lookup a remote port by port_id
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* @lport: The local port to lookup the remote port on
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* @port_id: The remote port ID to look up
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*
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* The caller must hold either disc_mutex or rcu_read_lock().
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*/
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static struct fc_rport_priv *fc_rport_lookup(const struct fc_lport *lport,
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u32 port_id)
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{
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struct fc_rport_priv *rdata;
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list_for_each_entry(rdata, &lport->disc.rports, peers)
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list_for_each_entry_rcu(rdata, &lport->disc.rports, peers)
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if (rdata->ids.port_id == port_id)
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return rdata;
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return NULL;
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@ -146,10 +148,22 @@ static struct fc_rport_priv *fc_rport_create(struct fc_lport *lport,
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INIT_DELAYED_WORK(&rdata->retry_work, fc_rport_timeout);
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INIT_WORK(&rdata->event_work, fc_rport_work);
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if (port_id != FC_FID_DIR_SERV)
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list_add(&rdata->peers, &lport->disc.rports);
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list_add_rcu(&rdata->peers, &lport->disc.rports);
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return rdata;
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}
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/**
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* fc_rport_free_rcu() - Free a remote port
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* @rcu: The rcu_head structure inside the remote port
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*/
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static void fc_rport_free_rcu(struct rcu_head *rcu)
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{
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struct fc_rport_priv *rdata;
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rdata = container_of(rcu, struct fc_rport_priv, rcu);
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kfree(rdata);
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}
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/**
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* fc_rport_destroy() - Free a remote port after last reference is released
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* @kref: The remote port's kref
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@ -159,7 +173,7 @@ static void fc_rport_destroy(struct kref *kref)
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struct fc_rport_priv *rdata;
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rdata = container_of(kref, struct fc_rport_priv, kref);
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kfree(rdata);
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call_rcu(&rdata->rcu, fc_rport_free_rcu);
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}
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/**
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@ -334,7 +348,7 @@ static void fc_rport_work(struct work_struct *work)
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mutex_unlock(&rdata->rp_mutex);
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} else {
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FC_RPORT_DBG(rdata, "work delete\n");
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list_del(&rdata->peers);
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list_del_rcu(&rdata->peers);
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mutex_unlock(&rdata->rp_mutex);
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kref_put(&rdata->kref, lport->tt.rport_destroy);
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}
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@ -195,6 +195,7 @@ struct fc_rport_libfc_priv {
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* @rp_mutex: The mutex that protects the remote port
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* @retry_work: Handle for retries
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* @event_callback: Callback when READY, FAILED or LOGO states complete
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* @rcu: Structure used for freeing in an RCU-safe manner
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*/
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struct fc_rport_priv {
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struct fc_lport *local_port;
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@ -217,6 +218,7 @@ struct fc_rport_priv {
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struct list_head peers;
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struct work_struct event_work;
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u32 supported_classes;
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struct rcu_head rcu;
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};
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/**
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