From 2f69a110e7bba3ec6bc089a2f736ca0941d887ed Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Thu, 5 Mar 2020 11:03:23 +0100
Subject: xen/xenbus: fix locking

Commit 060eabe8fbe726 ("xenbus/backend: Protect xenbus callback with
lock") introduced a bug by holding a lock while calling a function
which might schedule.

Fix that by using a semaphore instead.

Fixes: 060eabe8fbe726 ("xenbus/backend: Protect xenbus callback with lock")
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20200305100323.16736-1-jgross@suse.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
 include/xen/xenbus.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'include/xen')

diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index 89a889585ba0..850a43bd69d3 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -42,6 +42,7 @@
 #include <linux/completion.h>
 #include <linux/init.h>
 #include <linux/slab.h>
+#include <linux/semaphore.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/grant_table.h>
 #include <xen/interface/io/xenbus.h>
@@ -76,7 +77,7 @@ struct xenbus_device {
 	enum xenbus_state state;
 	struct completion down;
 	struct work_struct work;
-	spinlock_t reclaim_lock;
+	struct semaphore reclaim_sem;
 };
 
 static inline struct xenbus_device *to_xenbus_device(struct device *dev)
-- 
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