From: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Date: Wed, 29 Oct 2014 08:16:00 +0000 (+0200)
Subject: Bluetooth: Wrong style spin lock used
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9cfd5a23a49c2a2cb9ff5537128d03547cbd2990;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

Bluetooth: Wrong style spin lock used

Use spin_lock_bh() as the code is called from softirq in networking subsystem.
This is needed to prevent deadlocks when 6lowpan link is in use.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
---

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index ddf33900f7f3..91995f8ab0a0 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -4661,8 +4661,12 @@ static void hci_queue_acl(struct hci_chan *chan, struct sk_buff_head *queue,
 
 		skb_shinfo(skb)->frag_list = NULL;
 
-		/* Queue all fragments atomically */
-		spin_lock(&queue->lock);
+		/* Queue all fragments atomically. We need to use spin_lock_bh
+		 * here because of 6LoWPAN links, as there this function is
+		 * called from softirq and using normal spin lock could cause
+		 * deadlocks.
+		 */
+		spin_lock_bh(&queue->lock);
 
 		__skb_queue_tail(queue, skb);
 
@@ -4679,7 +4683,7 @@ static void hci_queue_acl(struct hci_chan *chan, struct sk_buff_head *queue,
 			__skb_queue_tail(queue, skb);
 		} while (list);
 
-		spin_unlock(&queue->lock);
+		spin_unlock_bh(&queue->lock);
 	}
 }