Revert "net/smc: don't req_notify until all CQEs drained"

This reverts commit a505cce6f7cfaf2aa2385aab7286063c96444526.

Leon says:
  We already discussed that. SMC should be changed to use
  RDMA CQ pool API
  drivers/infiniband/core/cq.c.
  ib_poll_handler() has much better implementation (tracing,
  IRQ rescheduling, proper error handling) than this SMC variant.

Since we will switch to ib_poll_handler() in the future,
revert this patch.

Link: https://lore.kernel.org/netdev/20220301105332.GA9417@linux.alibaba.com/
Suggested-by: Leon Romanovsky <leon@kernel.org>
Suggested-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
index 34d6164..24be1d0 100644 (file)
--- a/net/smc/smc_wr.c
+++ b/net/smc/smc_wr.c
@@ -137,28 +137,25 @@ static void smc_wr_tx_tasklet_fn(struct tasklet_struct *t)
 {
        struct smc_ib_device *dev = from_tasklet(dev, t, send_tasklet);
        struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
-       int i, rc;
+       int i = 0, rc;
+       int polled = 0;
 
 again:
+       polled++;
        do {
                memset(&wc, 0, sizeof(wc));
                rc = ib_poll_cq(dev->roce_cq_send, SMC_WR_MAX_POLL_CQE, wc);
+               if (polled == 1) {
+                       ib_req_notify_cq(dev->roce_cq_send,
+                                        IB_CQ_NEXT_COMP |
+                                        IB_CQ_REPORT_MISSED_EVENTS);
+               }
+               if (!rc)
+                       break;
                for (i = 0; i < rc; i++)
                        smc_wr_tx_process_cqe(&wc[i]);
-               if (rc < SMC_WR_MAX_POLL_CQE)
-                       /* If < SMC_WR_MAX_POLL_CQE, the CQ should have been
-                        * drained, no need to poll again. --Guangguan Wang
-                        */
-                       break;
        } while (rc > 0);
-
-       /* IB_CQ_REPORT_MISSED_EVENTS make sure if ib_req_notify_cq() returns
-        * 0, it is safe to wait for the next event.
-        * Else we must poll the CQ again to make sure we won't miss any event
-        */
-       if (ib_req_notify_cq(dev->roce_cq_send,
-                            IB_CQ_NEXT_COMP |
-                            IB_CQ_REPORT_MISSED_EVENTS))
+       if (polled == 1)
                goto again;
 }
 
@@ -481,28 +478,24 @@ static void smc_wr_rx_tasklet_fn(struct tasklet_struct *t)
 {
        struct smc_ib_device *dev = from_tasklet(dev, t, recv_tasklet);
        struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
+       int polled = 0;
        int rc;
 
 again:
+       polled++;
        do {
                memset(&wc, 0, sizeof(wc));
                rc = ib_poll_cq(dev->roce_cq_recv, SMC_WR_MAX_POLL_CQE, wc);
-               if (rc > 0)
-                       smc_wr_rx_process_cqes(&wc[0], rc);
-               if (rc < SMC_WR_MAX_POLL_CQE)
-                       /* If < SMC_WR_MAX_POLL_CQE, the CQ should have been
-                        * drained, no need to poll again. --Guangguan Wang
-                        */
+               if (polled == 1) {
+                       ib_req_notify_cq(dev->roce_cq_recv,
+                                        IB_CQ_SOLICITED_MASK
+                                        | IB_CQ_REPORT_MISSED_EVENTS);
+               }
+               if (!rc)
                        break;
+               smc_wr_rx_process_cqes(&wc[0], rc);
        } while (rc > 0);
-
-       /* IB_CQ_REPORT_MISSED_EVENTS make sure if ib_req_notify_cq() returns
-        * 0, it is safe to wait for the next event.
-        * Else we must poll the CQ again to make sure we won't miss any event
-        */
-       if (ib_req_notify_cq(dev->roce_cq_recv,
-                            IB_CQ_SOLICITED_MASK |
-                            IB_CQ_REPORT_MISSED_EVENTS))
+       if (polled == 1)
                goto again;
 }