From dc8fcb26807c734cf79d8a82d2ba655f226ad135 Mon Sep 17 00:00:00 2001
From: Frederic Robra
Date: Wed, 4 Sep 2019 15:10:03 +0200
Subject: prepared kernel module to have configurable number of connections

---
 src/kernel/core.c | 42 ++++++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 18 deletions(-)

(limited to 'src/kernel/core.c')

diff --git a/src/kernel/core.c b/src/kernel/core.c
index 6aa3b50..2f7ddcb 100644
--- a/src/kernel/core.c
+++ b/src/kernel/core.c
@@ -74,6 +74,7 @@ static int dnbd3_ioctl(struct block_device *bdev, fmode_t mode,
 		unsigned int cmd, unsigned long arg)
 {
 	int result = -EIO;
+	bool old_msg = false;
 	struct dnbd3_device *dev = bdev->bd_disk->private_data;
 	char *imgname = NULL;
 	dnbd3_ioctl_t *msg = NULL;
@@ -87,7 +88,12 @@ static int dnbd3_ioctl(struct block_device *bdev, fmode_t mode,
 			return -ENOMEM;
 		}
 		result = copy_from_user((char *)msg, (char *)arg, 2);
-		if (result != 0	|| msg->len != sizeof(*msg)) {
+		if (result != 0) {
+			result = -ENOEXEC;
+			goto error;
+		} else if (msg->len == 40){ /* old msg length was 40 */
+			old_msg = true;
+		} else if (msg->len != sizeof(*msg)) {
 			result = -ENOEXEC;
 			goto error;
 		}
@@ -146,6 +152,11 @@ static int dnbd3_ioctl(struct block_device *bdev, fmode_t mode,
 			memcpy(dev->alt_servers, &dev->initial_server,
 					sizeof(dev->alt_servers[0]));
 
+			if (old_msg || msg->number_connections == 0) {
+				dev->number_connections = 4;
+			} else {
+				dev->number_connections = msg->number_connections;
+			}
 			mutex_unlock(&dev->device_lock);
 
 			result = dnbd3_net_connect(dev);
@@ -209,8 +220,12 @@ static int dnbd3_ioctl(struct block_device *bdev, fmode_t mode,
 		break;
 	}
 error:
-	if (msg) kfree(msg);
-	if (imgname) kfree(imgname);
+	if (msg) {
+		kfree(msg);
+	}
+	if (imgname) {
+		kfree(imgname);
+	}
 	return result;
 
 }
@@ -240,19 +255,11 @@ int dnbd3_add_device(struct dnbd3_device *dev, int minor)
 	struct gendisk *disk;
 	struct request_queue *q;
 	int err = -ENOMEM;
-	int i;
 	debug("adding device %d", minor);
 
 	mutex_init(&dev->device_lock);
 	mutex_lock(&dev->device_lock);
 
-//	atomic_set(&dev->mq_requests, 0);
-	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
-		dev->socks[i].device = dev;
-		dev->socks[i].sock_nr = i;
-		mutex_init(&dev->socks[i].tx_lock);
-	}
-
 	disk = alloc_disk(1);
 	if (!disk) {
 		error_dev(dev, "allocating disc failed");
@@ -265,14 +272,15 @@ int dnbd3_add_device(struct dnbd3_device *dev, int minor)
 		err = -EEXIST;
 	}
 
-	if (err < 0)
+	if (err < 0) {
 		goto out_free_disk;
+	}
 
 	dev->minor = minor;
 	dev->disk = disk;
 	dev->tag_set.ops = &dnbd3_mq_ops;
 	/* this can be changed later with blk_mq_update_nr_hw_queues() */
-	dev->tag_set.nr_hw_queues = NUMBER_CONNECTIONS;
+	dev->tag_set.nr_hw_queues = 1;
 	dev->tag_set.queue_depth = 128;
 	dev->tag_set.numa_node = NUMA_NO_NODE;
 	dev->tag_set.cmd_size = sizeof(struct dnbd3_cmd);
@@ -404,9 +412,10 @@ static void dnbd3_dev_remove(struct dnbd3_device *dev)
 {
 	struct gendisk *disk = dev->disk;
 	struct request_queue *q;
-	int i;
 
-	dnbd3_net_disconnect(dev);
+	if (dev->connected) {
+		dnbd3_net_disconnect(dev);
+	}
 
 	if (disk) {
 		q = disk->queue;
@@ -421,9 +430,6 @@ static void dnbd3_dev_remove(struct dnbd3_device *dev)
 		dev->imgname = NULL;
 	}
 	mutex_destroy(&dev->device_lock);
-	for (i = 0; i < NUMBER_CONNECTIONS; i++) {
-		mutex_destroy(&dev->socks[i].tx_lock);
-	}
 }
 
 /**
-- 
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