From: Josef Bacik <jbacik@fb.com>
Date: Fri, 21 Jul 2017 14:48:14 +0000 (-0400)
Subject: nbd: take tx_lock before disconnecting
X-Git-Tag: v4.14-rc1~376^2~8
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b4b2aeccf0f0fa1fd356cc72eeda7a2c66c39904;p=platform%2Fkernel%2Flinux-rpi3.git

nbd: take tx_lock before disconnecting

We need to take the tx_lock so we don't interleave our disconnect
request between real data going down the wire.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index f91e7ac..6aefe9f 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -978,11 +978,15 @@ static void send_disconnects(struct nbd_device *nbd)
 	int i, ret;
 
 	for (i = 0; i < config->num_connections; i++) {
+		struct nbd_sock *nsock = config->socks[i];
+
 		iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
+		mutex_lock(&nsock->tx_lock);
 		ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
 		if (ret <= 0)
 			dev_err(disk_to_dev(nbd->disk),
 				"Send disconnect failed %d\n", ret);
+		mutex_unlock(&nsock->tx_lock);
 	}
 }