[PATCH] RDMA/bng_re: return a timeout when firmware responses stall

[Pengpeng Hou]

__wait_for_resp() documents that it returns a non-zero error when a
firmware command does not complete, and bng_re_rcfw_send_message() already
marks the firmware as stalled when the helper returns -ENODEV.

However, the helper ignores wait_event_timeout() expiry.  If the response
slot remains in use after the timeout and after the polled CREQ service
attempt, the loop starts another full timeout period and can repeat
forever.

Return -ENODEV after a timed out wait that still has no response.  The
existing caller then marks FIRMWARE_STALL_DETECTED and returns
-ETIMEDOUT to the command issuer.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 drivers/infiniband/hw/bng_re/bng_fw.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/bng_re/bng_fw.c b/drivers/infiniband/hw/bng_re/bng_fw.c
index 50156c300..ab6a2d2e9 100644
--- a/drivers/infiniband/hw/bng_re/bng_fw.c
+++ b/drivers/infiniband/hw/bng_re/bng_fw.c
@@ -401,14 +401,15 @@ static int __wait_for_resp(struct bng_re_rcfw *rcfw, u16 cookie)
 {
 	struct bng_re_cmdq_ctx *cmdq;
 	struct bng_re_crsqe *crsqe;
+	unsigned long time_left;
 
 	cmdq = &rcfw->cmdq;
 	crsqe = &rcfw->crsqe_tbl[cookie];
 
 	do {
-		wait_event_timeout(cmdq->waitq,
-				   !crsqe->is_in_used,
-				   secs_to_jiffies(rcfw->max_timeout));
+		time_left = wait_event_timeout(cmdq->waitq,
+					       !crsqe->is_in_used,
+					       secs_to_jiffies(rcfw->max_timeout));
 
 		if (!crsqe->is_in_used)
 			return 0;
@@ -417,6 +418,9 @@ static int __wait_for_resp(struct bng_re_rcfw *rcfw, u16 cookie)
 
 		if (!crsqe->is_in_used)
 			return 0;
+
+		if (!time_left)
+			return -ENODEV;
 	} while (true);
 };
 
-- 
2.50.1 (Apple Git-155)