IB/hfi1: Add fast and slow handlers for receive context

This patch eliminate special cases by adding a fast_handler member to the
receive context and changes to the fast handler as specified in the new
variable. Initialize the variable as soon as the setting for dma tail is
known when the context is created.

Setting fast path is called every time when any context has entered slow
path. Add function to check if contexts is using fast path and do not set
fast path when it is already done to improve RCD fastpath setting.

Link: https://lore.kernel.org/r/20200106134150.119356.87558.stgit@awfm-01.aw.intel.com
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Signed-off-by: Sadanand Warrier <sadanand.warrier@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 12 insertions, 54 deletions

diff --git a/drivers/infiniband/hw/hfi1/driver.c b/drivers/infiniband/hw/hfi1/driver.c
index 8374922ea6e5..3671191b5aed 100644
--- a/drivers/infiniband/hw/hfi1/driver.c
+++ b/drivers/infiniband/hw/hfi1/driver.c
@@ -883,9 +883,8 @@ bail:
 	return last;
 }
 
-static inline void set_nodma_rtail(struct hfi1_devdata *dd, u16 ctxt)
+static void set_all_fastpath(struct hfi1_devdata *dd, struct hfi1_ctxtdata *rcd)
 {
-	struct hfi1_ctxtdata *rcd;
 	u16 i;
 
 	/*
@@ -893,50 +892,17 @@ static inline void set_nodma_rtail(struct hfi1_devdata *dd, u16 ctxt)
 	 * interrupt handler only for that context. Otherwise, switch
 	 * interrupt handler for all statically allocated kernel contexts.
 	 */
-	if (ctxt >= dd->first_dyn_alloc_ctxt) {
-		rcd = hfi1_rcd_get_by_index_safe(dd, ctxt);
-		if (rcd) {
-			rcd->do_interrupt =
-				&handle_receive_interrupt_nodma_rtail;
-			hfi1_rcd_put(rcd);
-		}
-		return;
-	}
-
-	for (i = HFI1_CTRL_CTXT + 1; i < dd->first_dyn_alloc_ctxt; i++) {
-		rcd = hfi1_rcd_get_by_index(dd, i);
-		if (rcd)
-			rcd->do_interrupt =
-				&handle_receive_interrupt_nodma_rtail;
+	if (rcd->ctxt >= dd->first_dyn_alloc_ctxt && !rcd->is_vnic) {
+		hfi1_rcd_get(rcd);
+		hfi1_set_fast(rcd);
 		hfi1_rcd_put(rcd);
-	}
-}
-
-static inline void set_dma_rtail(struct hfi1_devdata *dd, u16 ctxt)
-{
-	struct hfi1_ctxtdata *rcd;
-	u16 i;
-
-	/*
-	 * For dynamically allocated kernel contexts (like vnic) switch
-	 * interrupt handler only for that context. Otherwise, switch
-	 * interrupt handler for all statically allocated kernel contexts.
-	 */
-	if (ctxt >= dd->first_dyn_alloc_ctxt) {
-		rcd = hfi1_rcd_get_by_index_safe(dd, ctxt);
-		if (rcd) {
-			rcd->do_interrupt =
-				&handle_receive_interrupt_dma_rtail;
-			hfi1_rcd_put(rcd);
-		}
 		return;
 	}
 
-	for (i = HFI1_CTRL_CTXT + 1; i < dd->first_dyn_alloc_ctxt; i++) {
+	for (i = HFI1_CTRL_CTXT + 1; i < dd->num_rcv_contexts; i++) {
 		rcd = hfi1_rcd_get_by_index(dd, i);
-		if (rcd)
-			rcd->do_interrupt =
-				&handle_receive_interrupt_dma_rtail;
+		if (rcd && (i < dd->first_dyn_alloc_ctxt || rcd->is_vnic))
+			hfi1_set_fast(rcd);
 		hfi1_rcd_put(rcd);
 	}
 }
@@ -952,7 +918,7 @@ void set_all_slowpath(struct hfi1_devdata *dd)
 		if (!rcd)
 			continue;
 		if (i < dd->first_dyn_alloc_ctxt || rcd->is_vnic)
-			rcd->do_interrupt = &handle_receive_interrupt;
+			rcd->do_interrupt = rcd->slow_handler;
 
 		hfi1_rcd_put(rcd);
 	}
@@ -1065,11 +1031,6 @@ int handle_receive_interrupt(struct hfi1_ctxtdata *rcd, int thread)
 		if (!get_dma_rtail_setting(rcd)) {
 			if (hfi1_seq_incr(rcd, rhf_rcv_seq(packet.rhf)))
 				last = RCV_PKT_DONE;
-			if (needset) {
-				dd_dev_info(dd, "Switching to NO_DMA_RTAIL\n");
-				set_nodma_rtail(dd, rcd->ctxt);
-				needset = 0;
-			}
 		} else {
 			if (packet.rhqoff == hdrqtail)
 				last = RCV_PKT_DONE;
@@ -1085,15 +1046,12 @@ int handle_receive_interrupt(struct hfi1_ctxtdata *rcd, int thread)
 				if (!last && lseq)
 					skip_pkt = 1;
 			}
-
-			if (needset) {
-				dd_dev_info(dd,
-					    "Switching to DMA_RTAIL\n");
-				set_dma_rtail(dd, rcd->ctxt);
-				needset = 0;
-			}
 		}
 
+		if (needset) {
+			needset = false;
+			set_all_fastpath(dd, rcd);
+		}
 		process_rcv_update(last, &packet);
 	}