From 33fea772862dc8d9dba7c2afb18b8d5442a70ee7 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Thu, 13 Aug 2020 16:01:24 +0200
Subject: [KERNEL] Try not to -EIO if no socket is connected

---
 src/kernel/core.c     |  1 +
 src/kernel/mq.c       | 27 ++++++++++++---------------
 src/kernel/net-txrx.c |  3 +++
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/kernel/core.c b/src/kernel/core.c
index a0854dd..a7b1048 100644
--- a/src/kernel/core.c
+++ b/src/kernel/core.c
@@ -404,6 +404,7 @@ error:
 	if (dnbd3_wq) {
 		destroy_workqueue(dnbd3_wq);
 	}
+	return retval;
 }
 
 /**
diff --git a/src/kernel/mq.c b/src/kernel/mq.c
index cc710b2..67b33df 100644
--- a/src/kernel/mq.c
+++ b/src/kernel/mq.c
@@ -178,14 +178,14 @@ static int dnbd3_handle_cmd(struct dnbd3_cmd *cmd, int index)
 	struct request *req = blk_mq_rq_from_pdu(cmd);
 	struct dnbd3_device *dev = cmd->dnbd3;
 	struct dnbd3_sock *sock;
-	int ret = -1;
+	int ret;
 
 //	debug_dev(dev, "handle request at position %lu, size %d, index %d",
 //			blk_rq_pos(req), blk_rq_bytes(req), index);
 
 
-	if (!dev->socks || !dnbd3_is_sock_alive(dev->socks[index])) {
-		error_dev(dev, "ending request device not connected");
+	if (!dev->socks) {
+		error_dev(dev, "ending request: device not connected");
 		dnbd3_end_cmd(cmd, BLK_STS_IOERR);
 		return -EIO;
 	}
@@ -193,27 +193,24 @@ static int dnbd3_handle_cmd(struct dnbd3_cmd *cmd, int index)
 
 	mutex_lock(&sock->tx_lock);
 	if (unlikely(!sock->sock)) {
-		mutex_unlock(&sock->tx_lock);
-		warn_sock(sock, "not connected");
-		return -EIO;
+		goto err;
 	}
 
 	blk_mq_start_request(req);
 	if (unlikely(sock->pending && sock->pending != req)) {
-		dnbd3_requeue_cmd(cmd);
-		ret = 0;
-		goto out;
+		goto err;
 	}
 
 	ret = dnbd3_send_request(sock, blk_mq_rq_from_pdu(cmd), cmd);
-	if (ret == -EAGAIN) {
-		error_dev(dev, "request send failed, requeueing");
-		dnbd3_requeue_cmd(cmd);
-		ret = 0;
+	if (ret > 0) {
+		mutex_unlock(&sock->tx_lock);
+		return 0;
 	}
-out:
+	error_dev(dev, "request send failed, requeueing");
+err:
 	mutex_unlock(&sock->tx_lock);
-	return ret;
+	dnbd3_requeue_cmd(cmd);
+	return 0;
 }
 
 /**
diff --git a/src/kernel/net-txrx.c b/src/kernel/net-txrx.c
index 51c684d..0402619 100644
--- a/src/kernel/net-txrx.c
+++ b/src/kernel/net-txrx.c
@@ -171,6 +171,9 @@ int dnbd3_send_request(struct dnbd3_sock *sock, struct request *req,
 	result = kernel_sendmsg(sock->sock, &msg, iov, iov_num, lng);
 	if (result != lng) {
 		error_sock(sock, "connection to server lost");
+		if (result >= 0) {
+			result = -EIO; // QnD fix
+		}
 		/*
 		 * this triggers:
 		 * kernel BUG at block/blk-mq.c:704!
-- 
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