From 63716d8cb4902e96ff4d2c8408e74421ea46f13f Mon Sep 17 00:00:00 2001
From: Sivaji Boddupilli <quic_boddupil@quicinc.com>
Date: Fri, 28 Jul 2023 18:29:34 +0530
Subject: [PATCH] net: qrtr: Handle -EAGAIN from MHI layer

Inifinite retry when MHI return -EAGAIN error instead of
5 times retry. This infinite wait QRTR MHI transport is
performing based on the return value (-EAGAIN) from the
MHI transport. This completion wait implementation will be
replaced with waitqueues model.

Change-Id: I1844214a3e45e744df3f547fbd8112ecf47bad63
Signed-off-by: Sivaji Boddupilli <quic_boddupil@quicinc.com>
---
 net/qrtr/mhi.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c
index e288c7c39a88..0858da40b538 100644
--- a/net/qrtr/mhi.c
+++ b/net/qrtr/mhi.c
@@ -20,6 +20,7 @@ struct qrtr_mhi_dev {
 	struct mhi_device *mhi_dev;
 	struct device *dev;
 	struct completion prepared;
+	struct completion ringfull;
 };
 
 /* From MHI to QRTR */
@@ -43,10 +44,13 @@ static void qcom_mhi_qrtr_ul_callback(struct mhi_device *mhi_dev,
 				      struct mhi_result *mhi_res)
 {
 	struct sk_buff *skb = mhi_res->buf_addr;
+	struct qrtr_mhi_dev *qdev = dev_get_drvdata(&mhi_dev->dev);
 
 	if (skb->sk)
 		sock_put(skb->sk);
 	consume_skb(skb);
+
+	complete_all(&qdev->ringfull);
 }
 
 /* Send data over MHI */
@@ -83,14 +87,16 @@ static int __qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
 
 static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
 {
+	struct qrtr_mhi_dev *qdev = container_of(ep, struct qrtr_mhi_dev, ep);
 	int rc;
-	int retry = 5;
 
 	do {
 		rc = __qcom_mhi_qrtr_send(ep, skb);
-		if (rc == -EAGAIN)
-			usleep_range(1000, 2000);
-	} while (rc == -EAGAIN && --retry);
+		if (rc == -EAGAIN) {
+			reinit_completion(&qdev->ringfull);
+			wait_for_completion(&qdev->ringfull);
+		}
+	} while (rc == -EAGAIN);
 
 	return rc;
 }
@@ -139,6 +145,7 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev,
 	qdev->dev = &mhi_dev->dev;
 	qdev->ep.xmit = qcom_mhi_qrtr_send;
 	init_completion(&qdev->prepared);
+	init_completion(&qdev->ringfull);
 
 	dev_set_drvdata(&mhi_dev->dev, qdev);