IB/srpt: Simplify channel state management

The only allowed channel state changes are those that change
the channel state into a state with a higher numerical value.
This allows to merge the functions srpt_set_ch_state() and
srpt_test_and_set_ch_state() into a single function.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Alex Estrin <alex.estrin@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 716f4292838a0007866cb65f9670fdeaa3ebd897..863fdd130b2b099dc729c25442d23f96ab7fcd10 100644 (file)
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -96,37 +96,25 @@ static int srpt_queue_status(struct se_cmd *cmd);
 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);
 
-static enum rdma_ch_state
-srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new_state)
-{
-       unsigned long flags;
-       enum rdma_ch_state prev;
-
-       spin_lock_irqsave(&ch->spinlock, flags);
-       prev = ch->state;
-       ch->state = new_state;
-       spin_unlock_irqrestore(&ch->spinlock, flags);
-       return prev;
-}
-
-/**
- * srpt_test_and_set_ch_state() - Test and set the channel state.
- *
- * Returns true if and only if the channel state has been set to the new state.
+/*
+ * The only allowed channel state changes are those that change the channel
+ * state into a state with a higher numerical value. Hence the new > prev test.
  */
-static bool
-srpt_test_and_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state old,
-                          enum rdma_ch_state new)
+static bool srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new)
 {
        unsigned long flags;
        enum rdma_ch_state prev;
+       bool changed = false;
 
        spin_lock_irqsave(&ch->spinlock, flags);
        prev = ch->state;
-       if (prev == old)
+       if (new > prev) {
                ch->state = new;
+               changed = true;
+       }
        spin_unlock_irqrestore(&ch->spinlock, flags);
-       return prev == old;
+
+       return changed;
 }
 
 /**
@@ -199,8 +187,7 @@ static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
                ib_cm_notify(ch->cm_id, event->event);
                break;
        case IB_EVENT_QP_LAST_WQE_REACHED:
-               if (srpt_test_and_set_ch_state(ch, CH_DRAINING,
-                                              CH_RELEASING))
+               if (srpt_set_ch_state(ch, CH_RELEASING))
                        srpt_release_channel(ch);
                else
                        pr_debug("%s: state %d - ignored LAST_WQE.\n",
@@ -1947,12 +1934,7 @@ static void srpt_drain_channel(struct ib_cm_id *cm_id)
        spin_lock_irq(&sdev->spinlock);
        list_for_each_entry(ch, &sdev->rch_list, list) {
                if (ch->cm_id == cm_id) {
-                       do_reset = srpt_test_and_set_ch_state(ch,
-                                       CH_CONNECTING, CH_DRAINING) ||
-                                  srpt_test_and_set_ch_state(ch,
-                                       CH_LIVE, CH_DRAINING) ||
-                                  srpt_test_and_set_ch_state(ch,
-                                       CH_DISCONNECTING, CH_DRAINING);
+                       do_reset = srpt_set_ch_state(ch, CH_DRAINING);
                        break;
                }
        }
@@ -2353,7 +2335,7 @@ static void srpt_cm_rtu_recv(struct ib_cm_id *cm_id)
        ch = srpt_find_channel(cm_id->context, cm_id);
        BUG_ON(!ch);
 
-       if (srpt_test_and_set_ch_state(ch, CH_CONNECTING, CH_LIVE)) {
+       if (srpt_set_ch_state(ch, CH_LIVE)) {
                struct srpt_recv_ioctx *ioctx, *ioctx_tmp;
 
                ret = srpt_ch_qp_rts(ch, ch->qp);