[PATCH for-next 10/17] RDMA/bnxt_re: handle command completions after driver detect a timedout

[Selvin Xavier <selvin.xavier@broadcom.com>]

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From: Kashyap Desai <kashyap.desai@broadcom.com>

If calling context detect command timeout, associated memory stored on
stack will not be valid. If firmware complete the same command later,
this causes incorrect memory access by driver.

Added is_waiter_alive to handle delayed completion by firmware.
is_waiter_alive is set and reset under command queue lock.

Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
---
 drivers/infiniband/hw/bnxt_re/qplib_rcfw.c | 46 +++++++++++++++++++-----------
 drivers/infiniband/hw/bnxt_re/qplib_rcfw.h |  1 +
 2 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
index 3215f8a..e105961 100644
--- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
+++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
@@ -216,6 +216,7 @@ static int __send_message(struct bnxt_qplib_rcfw *rcfw,
 	crsqe->free_slots = free_slots;
 	crsqe->resp = (struct creq_qp_event *)msg->resp;
 	crsqe->resp->cookie = cpu_to_le16(cookie);
+	crsqe->is_waiter_alive = true;
 	crsqe->req_size = __get_cmdq_base_cmd_size(msg->req, msg->req_sz);
 	if (__get_cmdq_base_resp_size(msg->req, msg->req_sz) && msg->sb) {
 		struct bnxt_qplib_rcfw_sbuf *sbuf = msg->sb;
@@ -347,7 +348,9 @@ static int __bnxt_qplib_rcfw_send_message(struct bnxt_qplib_rcfw *rcfw,
 					  struct bnxt_qplib_cmdqmsg *msg)
 {
 	struct creq_qp_event *evnt = (struct creq_qp_event *)msg->resp;
-	u16 cookie;
+	struct bnxt_qplib_crsqe *crsqe;
+	unsigned long flags;
+	u16 cookie, cbit;
 	int rc = 0;
 	u8 opcode;
 
@@ -363,6 +366,7 @@ static int __bnxt_qplib_rcfw_send_message(struct bnxt_qplib_rcfw *rcfw,
 
 	cookie = le16_to_cpu(__get_cmdq_base_cookie(msg->req, msg->req_sz))
 				& RCFW_MAX_COOKIE_VALUE;
+	cbit = cookie % rcfw->cmdq_depth;
 
 	if (msg->block)
 		rc = __block_for_resp(rcfw, cookie, opcode);
@@ -378,6 +382,14 @@ static int __bnxt_qplib_rcfw_send_message(struct bnxt_qplib_rcfw *rcfw,
 		return rc;
 	}
 
+	if (rc) {
+		spin_lock_irqsave(&rcfw->cmdq.hwq.lock, flags);
+		crsqe = &rcfw->crsqe_tbl[cbit];
+		crsqe->is_waiter_alive = false;
+		spin_unlock_irqrestore(&rcfw->cmdq.hwq.lock, flags);
+		return -ETIMEDOUT;
+	}
+
 	if (evnt->status) {
 		/* failed with status */
 		dev_err(&rcfw->pdev->dev, "cmdq[%#x]=%#x status %#x\n",
@@ -480,15 +492,16 @@ static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw,
 	struct creq_qp_error_notification *err_event;
 	struct bnxt_qplib_hwq *hwq = &rcfw->cmdq.hwq;
 	struct bnxt_qplib_crsqe *crsqe;
+	u32 qp_id, tbl_indx, req_size;
 	struct bnxt_qplib_qp *qp;
 	u16 cbit, blocked = 0;
+	bool is_waiter_alive;
 	struct pci_dev *pdev;
 	unsigned long flags;
 	u32 wait_cmds = 0;
 	__le16  mcookie;
 	u16 cookie;
 	int rc = 0;
-	u32 qp_id, tbl_indx;
 
 	pdev = rcfw->pdev;
 	switch (qp_event->event) {
@@ -525,26 +538,25 @@ static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw,
 		cookie &= RCFW_MAX_COOKIE_VALUE;
 		cbit = cookie % rcfw->cmdq_depth;
 		crsqe = &rcfw->crsqe_tbl[cbit];
-		if (crsqe->resp &&
-		    crsqe->resp->cookie  == mcookie) {
-			memcpy(crsqe->resp, qp_event, sizeof(*qp_event));
-			crsqe->resp = NULL;
-		} else {
-			if (crsqe->resp && crsqe->resp->cookie)
-				dev_err(&pdev->dev,
-					"CMD %s cookie sent=%#x, recd=%#x\n",
-					crsqe->resp ? "mismatch" : "collision",
-					crsqe->resp ? crsqe->resp->cookie : 0,
-					mcookie);
-		}
 		if (!test_and_clear_bit(cbit, rcfw->cmdq.cmdq_bitmap))
 			dev_warn(&pdev->dev,
 				 "CMD bit %d was not requested\n", cbit);
-		hwq->cons += crsqe->req_size;
+
+		if (crsqe->is_waiter_alive) {
+			if (crsqe->resp)
+				memcpy(crsqe->resp, qp_event, sizeof(*qp_event));
+			if (!blocked)
+				wait_cmds++;
+		}
+
+		req_size = crsqe->req_size;
+		is_waiter_alive = crsqe->is_waiter_alive;
+
 		crsqe->req_size = 0;
+		if (!is_waiter_alive)
+			crsqe->resp = NULL;
 
-		if (!blocked)
-			wait_cmds++;
+		hwq->cons += req_size;
 		spin_unlock_irqrestore(&hwq->lock, flags);
 	}
 	*num_wait += wait_cmds;
diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.h b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.h
index 089e616..6ed81c1 100644
--- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.h
+++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.h
@@ -152,6 +152,7 @@ struct bnxt_qplib_crsqe {
 	u32			req_size;
 	/* Free slots at the time of submission */
 	u32			free_slots;
+	bool			is_waiter_alive;
 };
 
 struct bnxt_qplib_rcfw_sbuf {
-- 
2.5.5


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