IB/ipath: Wait for PIO available interrupt

The send function is called when posting new send work requests.
There is no point in trying to send a packet if the QP is already
waiting for a HW send buffer so don't clear the busy bit until the
buffer available interrupt happens.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

2 files changed, 3 insertions, 4 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_ruc.c b/drivers/infiniband/hw/ipath/ipath_ruc.c
index 8c5d20a4b5f3..837118676cc7 100644
--- a/drivers/infiniband/hw/ipath/ipath_ruc.c
+++ b/drivers/infiniband/hw/ipath/ipath_ruc.c
@@ -503,11 +503,9 @@ void ipath_no_bufs_available(struct ipath_qp *qp, struct ipath_ibdev *dev)
          * could be called.  If we are still in the tasklet function,
          * tasklet_hi_schedule() will not call us until the next time
          * tasklet_hi_schedule() is called.
-         * We clear the tasklet flag now since we are committing to return
-         * from the tasklet function.
+         * We leave the busy flag set so that another post send doesn't
+         * try to put the same QP on the piowait list again.
          */
-        clear_bit(IPATH_S_BUSY, &qp->s_busy);
-        tasklet_unlock(&qp->s_task);
         want_buffer(dev->dd);
         dev->n_piowait++;
 }
diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.c b/drivers/infiniband/hw/ipath/ipath_verbs.c
index 04294ca0a81f..cd79a8ca5104 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.c
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.c
@@ -948,6 +948,7 @@ int ipath_ib_piobufavail(struct ipath_ibdev *dev)
                 qp = list_entry(dev->piowait.next, struct ipath_qp,
                                 piowait);
                 list_del_init(&qp->piowait);
+                clear_bit(IPATH_S_BUSY, &qp->s_busy);
                 tasklet_hi_schedule(&qp->s_task);
         }
         spin_unlock_irqrestore(&dev->pending_lock, flags);