ntb: stop tasklet from spinning forever during shutdown.
authorDave Jiang <dave.jiang@intel.com>
Tue, 23 Feb 2016 16:11:36 +0000 (09:11 -0700)
committerJon Mason <jdmason@kudzu.us>
Fri, 18 Mar 2016 00:38:40 +0000 (20:38 -0400)
We can leave tasklet spinning forever if we disable the tasklet during
qp shutdown and the tasklets are still being kicked off. This hopefully
should avoid that race condition.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reported-by: Alex Depoutovitch <alex@pernixdata.com>
Tested-by: Alex Depoutovitch <alex@pernixdata.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
drivers/ntb/ntb_transport.c

index ec4775f0ec163a2ac4e3d89851bedfb4a0d52db1..4321488d21795233dff7668db612280222c1c84b 100644 (file)
@@ -124,6 +124,7 @@ struct ntb_transport_qp {
 
        bool client_ready;
        bool link_is_up;
+       bool active;
 
        u8 qp_num;      /* Only 64 QP's are allowed.  0-63 */
        u64 qp_bit;
@@ -719,6 +720,7 @@ static int ntb_set_mw(struct ntb_transport_ctx *nt, int num_mw,
 static void ntb_qp_link_down_reset(struct ntb_transport_qp *qp)
 {
        qp->link_is_up = false;
+       qp->active = false;
 
        qp->tx_index = 0;
        qp->rx_index = 0;
@@ -926,11 +928,13 @@ static void ntb_qp_link_work(struct work_struct *work)
        if (val & BIT(qp->qp_num)) {
                dev_info(&pdev->dev, "qp %d: Link Up\n", qp->qp_num);
                qp->link_is_up = true;
+               qp->active = true;
 
                if (qp->event_handler)
                        qp->event_handler(qp->cb_data, qp->link_is_up);
 
-               tasklet_schedule(&qp->rxc_db_work);
+               if (qp->active)
+                       tasklet_schedule(&qp->rxc_db_work);
        } else if (nt->link_is_up)
                schedule_delayed_work(&qp->link_work,
                                      msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT));
@@ -1411,7 +1415,8 @@ static void ntb_transport_rxc_db(unsigned long data)
 
        if (i == qp->rx_max_entry) {
                /* there is more work to do */
-               tasklet_schedule(&qp->rxc_db_work);
+               if (qp->active)
+                       tasklet_schedule(&qp->rxc_db_work);
        } else if (ntb_db_read(qp->ndev) & BIT_ULL(qp->qp_num)) {
                /* the doorbell bit is set: clear it */
                ntb_db_clear(qp->ndev, BIT_ULL(qp->qp_num));
@@ -1422,7 +1427,8 @@ static void ntb_transport_rxc_db(unsigned long data)
                 * ntb_process_rxc and clearing the doorbell bit:
                 * there might be some more work to do.
                 */
-               tasklet_schedule(&qp->rxc_db_work);
+               if (qp->active)
+                       tasklet_schedule(&qp->rxc_db_work);
        }
 }
 
@@ -1760,6 +1766,8 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp)
 
        pdev = qp->ndev->pdev;
 
+       qp->active = false;
+
        if (qp->tx_dma_chan) {
                struct dma_chan *chan = qp->tx_dma_chan;
                /* Putting the dma_chan to NULL will force any new traffic to be
@@ -1793,7 +1801,7 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp)
        qp_bit = BIT_ULL(qp->qp_num);
 
        ntb_db_set_mask(qp->ndev, qp_bit);
-       tasklet_disable(&qp->rxc_db_work);
+       tasklet_kill(&qp->rxc_db_work);
 
        cancel_delayed_work_sync(&qp->link_work);
 
@@ -1886,7 +1894,8 @@ int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
 
        ntb_list_add(&qp->ntb_rx_q_lock, &entry->entry, &qp->rx_pend_q);
 
-       tasklet_schedule(&qp->rxc_db_work);
+       if (qp->active)
+               tasklet_schedule(&qp->rxc_db_work);
 
        return 0;
 }
@@ -2069,7 +2078,8 @@ static void ntb_transport_doorbell_callback(void *data, int vector)
                qp_num = __ffs(db_bits);
                qp = &nt->qp_vec[qp_num];
 
-               tasklet_schedule(&qp->rxc_db_work);
+               if (qp->active)
+                       tasklet_schedule(&qp->rxc_db_work);
 
                db_bits &= ~BIT_ULL(qp_num);
        }