From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds proper qla_tgt_sess->sess_kref operation for
qla_tgt_sess reference and two flavours of qla_tgt_unreg_sess()
in order to have a qla_hw_data->hardware_lock lock-less method
to execute qla_tgt_cmd in qla_tgt_do_work() process context.
It also convert existing ->hardware_lock held qla_tgt_sess_put()
callers to use __qla_tgt_sess_put()
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Roland Dreier <roland@xxxxxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/scsi/qla2xxx/qla_target.c | 85 ++++++++++++-----------
drivers/scsi/qla2xxx/qla_target.h | 4 +-
drivers/target/tcm_qla2xxx/tcm_qla2xxx_fabric.c | 2 +-
3 files changed, 47 insertions(+), 44 deletions(-)
diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
index 9496c6f..3a9aa44 100644
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -125,27 +125,6 @@ static LIST_HEAD(qla_tgt_glist);
*/
extern request_t *qla2x00_req_pkt(struct scsi_qla_host *);
-/* ha->hardware_lock supposed to be held on entry */
-static inline void qla_tgt_sess_get(struct qla_tgt_sess *sess)
-{
- sess->sess_ref++;
- ql_dbg(ql_dbg_tgt, sess->vha, 0xe000, "sess %p, new sess_ref %d\n",
- sess, sess->sess_ref);
-}
-
-/* ha->hardware_lock supposed to be held on entry */
-void qla_tgt_sess_put(struct qla_tgt_sess *sess)
-{
- ql_dbg(ql_dbg_tgt, sess->vha, 0xe001, "sess %p, new sess_ref %d\n",
- sess, sess->sess_ref-1);
- BUG_ON(sess->sess_ref == 0);
-
- sess->sess_ref--;
- if (sess->sess_ref == 0)
- qla_tgt_unreg_sess(sess);
-}
-EXPORT_SYMBOL(qla_tgt_sess_put);
-
/* ha->hardware_lock supposed to be held on entry (to protect tgt->sess_list) */
static struct qla_tgt_sess *qla_tgt_find_sess_by_port_name(
struct qla_tgt *tgt,
@@ -408,13 +387,10 @@ static void qla_tgt_free_session_done(struct qla_tgt_sess *sess)
wake_up_all(&tgt->waitQ);
}
-/* ha->hardware_lock supposed to be held on entry */
-static int qla_tgt_unreg_sess(struct qla_tgt_sess *sess)
+static void __qla_tgt_unreg_sess(struct kref *kref)
{
- int res = 1;
-
- BUG_ON(sess == NULL);
- BUG_ON(sess->sess_ref != 0);
+ struct qla_tgt_sess *sess = container_of(kref, struct qla_tgt_sess,
+ sess_kref);
list_del(&sess->sess_list_entry);
@@ -426,8 +402,32 @@ static int qla_tgt_unreg_sess(struct qla_tgt_sess *sess)
sess->loop_id);
qla_tgt_free_session_done(sess);
+}
- return res;
+/* ha->hardware_lock supposed to be held on entry */
+static void qla_tgt_unreg_sess(struct kref *kref)
+{
+ struct qla_tgt_sess *sess = container_of(kref, struct qla_tgt_sess,
+ sess_kref);
+ struct scsi_qla_host *vha = sess->vha;
+ unsigned long flags;
+
+ spin_lock_irqsave(&vha->hw->hardware_lock, flags);
+ __qla_tgt_unreg_sess(kref);
+ spin_unlock_irqrestore(&vha->hw->hardware_lock, flags);
+}
+
+/* ha->hardware_lock supposed to be held on entry */
+int __qla_tgt_sess_put(struct qla_tgt_sess *sess)
+{
+ return kref_put(&sess->sess_kref, __qla_tgt_unreg_sess);
+}
+EXPORT_SYMBOL(__qla_tgt_sess_put);
+
+/* called without ha->hardware_lock held */
+static int qla_tgt_sess_put(struct qla_tgt_sess *sess)
+{
+ return kref_put(&sess->sess_kref, qla_tgt_unreg_sess);
}
/* ha->hardware_lock supposed to be held on entry */
@@ -783,7 +783,7 @@ static void qla_tgt_del_sess_work_fn(struct delayed_work *work)
} else {
ql_dbg(ql_dbg_tgt_mgt, vha, 0xe107, "Timeout: sess %p"
" about to be deleted\n", sess);
- qla_tgt_sess_put(sess);
+ __qla_tgt_sess_put(sess);
}
} else {
schedule_delayed_work(&tgt->sess_del_work,
@@ -858,11 +858,15 @@ static struct qla_tgt_sess *qla_tgt_create_sess(
return NULL;
}
+ /*
+ * Take two references to ->sess_kref here to handle qla_tgt_sess
+ * access across ->hardware_lock reaquire.
+ */
+ kref_init(&sess->sess_kref);
+ kref_get(&sess->sess_kref);
- sess->sess_ref = 2; /* plus 1 extra ref, see above */
sess->tgt = ha->qla_tgt;
sess->vha = vha;
-
sess->s_id = fcport->d_id;
sess->loop_id = fcport->loop_id;
sess->local = local;
@@ -942,8 +946,9 @@ void qla_tgt_fc_port_added(struct scsi_qla_host *vha, fc_port_t *fcport)
mutex_unlock(&ha->tgt_mutex);
spin_lock_irqsave(&ha->hardware_lock, flags);
+ /* put the extra creation ref */
if (sess != NULL)
- qla_tgt_sess_put(sess); /* put the extra creation ref */
+ __qla_tgt_sess_put(sess);
} else {
if (sess->deleted) {
qla_tgt_undelete_sess(sess);
@@ -4589,7 +4594,7 @@ static void qla_tgt_exec_cmd_work(struct work_struct *work)
if (sess) {
ql_dbg(ql_dbg_tgt_mgt, vha, 0xe14c, "sess %p found\n", sess);
- qla_tgt_sess_get(sess);
+ kref_get(&sess->sess_kref);
} else {
spin_unlock_irqrestore(&ha->hardware_lock, flags);
@@ -4674,7 +4679,7 @@ static void qla_tgt_abort_work(struct qla_tgt *tgt,
if (sess) {
ql_dbg(ql_dbg_tgt_mgt, vha, 0xe14c, "sess %p found\n", sess);
- qla_tgt_sess_get(sess);
+ kref_get(&sess->sess_kref);
} else {
spin_unlock_irqrestore(&ha->hardware_lock, flags);
@@ -4700,8 +4705,7 @@ static void qla_tgt_abort_work(struct qla_tgt *tgt,
goto out_term;
if (sess)
- qla_tgt_sess_put(sess);
-
+ __qla_tgt_sess_put(sess);
spin_unlock_irqrestore(&ha->hardware_lock, flags);
return;
@@ -4715,8 +4719,7 @@ out_term:
}
if (sess)
- qla_tgt_sess_put(sess);
-
+ __qla_tgt_sess_put(sess);
spin_unlock_irqrestore(&ha->hardware_lock, flags);
}
@@ -4748,7 +4751,7 @@ static void qla_tgt_tmr_work(struct qla_tgt *tgt,
if (sess) {
ql_dbg(ql_dbg_tgt_mgt, vha, 0xe14c, "sess %p found\n", sess);
- qla_tgt_sess_get(sess);
+ kref_get(&sess->sess_kref);
} else {
spin_unlock_irqrestore(&ha->hardware_lock, flags);
@@ -4784,7 +4787,7 @@ static void qla_tgt_tmr_work(struct qla_tgt *tgt,
goto out_term;
if (sess)
- qla_tgt_sess_put(sess);
+ __qla_tgt_sess_put(sess);
spin_unlock_irqrestore(&ha->hardware_lock, flags);
return;
@@ -4795,7 +4798,7 @@ out_term:
qla_tgt_send_notify_ack(vha, &prm->tm_iocb,
0, 0, 0, 0, 0, 0);
if (sess)
- qla_tgt_sess_put(sess);
+ __qla_tgt_sess_put(sess);
spin_unlock_irqrestore(&ha->hardware_lock, flags);
}
diff --git a/drivers/scsi/qla2xxx/qla_target.h b/drivers/scsi/qla2xxx/qla_target.h
index e868490..a9032d6 100644
--- a/drivers/scsi/qla2xxx/qla_target.h
+++ b/drivers/scsi/qla2xxx/qla_target.h
@@ -905,7 +905,7 @@ struct qla_tgt_sess {
struct scsi_qla_host *vha;
struct qla_tgt *tgt;
- int sess_ref; /* protected by hardware_lock */
+ struct kref sess_kref;
struct list_head sess_list_entry;
unsigned long expires;
@@ -1123,7 +1123,7 @@ extern int qla_tgt_xmit_response(struct qla_tgt_cmd *, int, uint8_t);
extern void qla_tgt_xmit_tm_rsp(struct qla_tgt_mgmt_cmd *);
extern void qla_tgt_free_mcmd(struct qla_tgt_mgmt_cmd *);
extern void qla_tgt_free_cmd(struct qla_tgt_cmd *cmd);
-extern void qla_tgt_sess_put(struct qla_tgt_sess *);
+extern int __qla_tgt_sess_put(struct qla_tgt_sess *);
extern void qla_tgt_ctio_completion(struct scsi_qla_host *, uint32_t);
extern void qla_tgt_async_event(uint16_t, struct scsi_qla_host *, uint16_t *);
extern void qla_tgt_enable_vha(struct scsi_qla_host *);
diff --git a/drivers/target/tcm_qla2xxx/tcm_qla2xxx_fabric.c b/drivers/target/tcm_qla2xxx/tcm_qla2xxx_fabric.c
index 8fe8710..c1080e2 100644
--- a/drivers/target/tcm_qla2xxx/tcm_qla2xxx_fabric.c
+++ b/drivers/target/tcm_qla2xxx/tcm_qla2xxx_fabric.c
@@ -481,7 +481,7 @@ void tcm_qla2xxx_close_session(struct se_session *se_sess)
spin_lock_irqsave(&vha->hw->hardware_lock, flags);
tcm_qla2xxx_clear_nacl_from_fcport_map(se_nacl);
- qla_tgt_sess_put(sess);
+ __qla_tgt_sess_put(sess);
spin_unlock_irqrestore(&vha->hw->hardware_lock, flags);
}
--
1.7.2.5
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