RDMA/bnxt_re: Fix broken RoCE driver due to recent L2 driver changes

The recent changes in Broadcom's ethernet driver(L2 driver) broke
RoCE functionality in terms of MSIx vector allocation and
de-allocation.

There is a possibility that L2 driver would initiate MSIx vector
reallocation depending upon the requests coming from administrator.
In such cases L2 driver needs to free up all the MSIx vectors
allocated previously and reallocate/initialize those.

If RoCE driver is loaded and reshuffling is attempted, there will be
kernel crashes because RoCE driver would still be holding the MSIx
vectors but L2 driver would attempt to free in-use vectors. Thus
leading to a kernel crash.

Making changes in roce driver to fix crashes described above.
As part of solution L2 driver tells RoCE driver to release
the MSIx vector whenever there is a need. When RoCE driver
get message it sync up with all the running tasklets and IRQ
handlers and releases the vectors. L2 driver send one more
message to RoCE driver to resume the MSIx vectors. L2 driver
guarantees that RoCE vector do not change during reshuffling.

Fixes: ec86f14ea506 ("bnxt_en: Add ULP calls to stop and restart IRQs.")
Fixes: 08654eb213a8 ("bnxt_en: Change IRQ assignment for RDMA driver.")
Signed-off-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 43 insertions, 18 deletions

diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
index 80027a494730..2852d350ada1 100644
--- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
+++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
@@ -582,19 +582,29 @@ fail:
 	return -ENOMEM;
 }
 
-void bnxt_qplib_disable_rcfw_channel(struct bnxt_qplib_rcfw *rcfw)
+void bnxt_qplib_rcfw_stop_irq(struct bnxt_qplib_rcfw *rcfw, bool kill)
 {
-	unsigned long indx;
-
-	/* Make sure the HW channel is stopped! */
-	synchronize_irq(rcfw->vector);
 	tasklet_disable(&rcfw->worker);
-	tasklet_kill(&rcfw->worker);
+	/* Mask h/w interrupts */
+	CREQ_DB(rcfw->creq_bar_reg_iomem, rcfw->creq.cons,
+		rcfw->creq.max_elements);
+	/* Sync with last running IRQ-handler */
+	synchronize_irq(rcfw->vector);
+	if (kill)
+		tasklet_kill(&rcfw->worker);
 
 	if (rcfw->requested) {
 		free_irq(rcfw->vector, rcfw);
 		rcfw->requested = false;
 	}
+}
+
+void bnxt_qplib_disable_rcfw_channel(struct bnxt_qplib_rcfw *rcfw)
+{
+	unsigned long indx;
+
+	bnxt_qplib_rcfw_stop_irq(rcfw, true);
+
 	if (rcfw->cmdq_bar_reg_iomem)
 		iounmap(rcfw->cmdq_bar_reg_iomem);
 	rcfw->cmdq_bar_reg_iomem = NULL;
@@ -614,6 +624,31 @@ void bnxt_qplib_disable_rcfw_channel(struct bnxt_qplib_rcfw *rcfw)
 	rcfw->vector = 0;
 }
 
+int bnxt_qplib_rcfw_start_irq(struct bnxt_qplib_rcfw *rcfw, int msix_vector,
+			      bool need_init)
+{
+	int rc;
+
+	if (rcfw->requested)
+		return -EFAULT;
+
+	rcfw->vector = msix_vector;
+	if (need_init)
+		tasklet_init(&rcfw->worker,
+			     bnxt_qplib_service_creq, (unsigned long)rcfw);
+	else
+		tasklet_enable(&rcfw->worker);
+	rc = request_irq(rcfw->vector, bnxt_qplib_creq_irq, 0,
+			 "bnxt_qplib_creq", rcfw);
+	if (rc)
+		return rc;
+	rcfw->requested = true;
+	CREQ_DB_REARM(rcfw->creq_bar_reg_iomem, rcfw->creq.cons,
+		      rcfw->creq.max_elements);
+
+	return 0;
+}
+
 int bnxt_qplib_enable_rcfw_channel(struct pci_dev *pdev,
 				   struct bnxt_qplib_rcfw *rcfw,
 				   int msix_vector,
@@ -675,27 +710,17 @@ int bnxt_qplib_enable_rcfw_channel(struct pci_dev *pdev,
 	rcfw->creq_qp_event_processed = 0;
 	rcfw->creq_func_event_processed = 0;
 
-	rcfw->vector = msix_vector;
 	if (aeq_handler)
 		rcfw->aeq_handler = aeq_handler;
+	init_waitqueue_head(&rcfw->waitq);
 
-	tasklet_init(&rcfw->worker, bnxt_qplib_service_creq,
-		     (unsigned long)rcfw);
-
-	rcfw->requested = false;
-	rc = request_irq(rcfw->vector, bnxt_qplib_creq_irq, 0,
-			 "bnxt_qplib_creq", rcfw);
+	rc = bnxt_qplib_rcfw_start_irq(rcfw, msix_vector, true);
 	if (rc) {
 		dev_err(&rcfw->pdev->dev,
 			"QPLIB: Failed to request IRQ for CREQ rc = 0x%x", rc);
 		bnxt_qplib_disable_rcfw_channel(rcfw);
 		return rc;
 	}
-	rcfw->requested = true;
-
-	init_waitqueue_head(&rcfw->waitq);
-
-	CREQ_DB_REARM(rcfw->creq_bar_reg_iomem, 0, rcfw->creq.max_elements);
 
 	init.cmdq_pbl = cpu_to_le64(rcfw->cmdq.pbl[PBL_LVL_0].pg_map_arr[0]);
 	init.cmdq_size_cmdq_lvl = cpu_to_le16(