Re: Linux 5.10.274

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

diff --git a/Makefile b/Makefile
index 0e5cf0c2083f..73daa0bf2028 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 5
 PATCHLEVEL = 10
-SUBLEVEL = 273
+SUBLEVEL = 274
 EXTRAVERSION =
 NAME = Dare mighty things
 
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 5eff34767b77..e923e8cd1f04 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -318,8 +318,10 @@ struct xen_blkif {
 	unsigned int 		nr_ring_pages;
 	bool			multi_ref;
 	/* All rings for this device. */
+	rwlock_t		rings_lock;
 	struct xen_blkif_ring	*rings;
 	unsigned int		nr_rings;
+
 	unsigned long		buffer_squeeze_end;
 };
 
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index ddea36295931..bdfd8d4042b5 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -127,15 +127,23 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
 	return;
 }
 
-static int xen_blkif_alloc_rings(struct xen_blkif *blkif)
+static int xen_blkif_alloc_rings(struct xen_blkif *blkif,
+				 unsigned int nr_rings)
 {
 	unsigned int r;
+	struct xen_blkif_ring *rings;
 
-	blkif->rings = kcalloc(blkif->nr_rings, sizeof(struct xen_blkif_ring),
-			       GFP_KERNEL);
-	if (!blkif->rings)
+	rings = kcalloc(nr_rings, sizeof(struct xen_blkif_ring), GFP_KERNEL);
+	if (!rings)
 		return -ENOMEM;
 
+	write_lock(&blkif->rings_lock);
+
+	blkif->rings = rings;
+	blkif->nr_rings = nr_rings;
+
+	write_unlock(&blkif->rings_lock);
+
 	for (r = 0; r < blkif->nr_rings; r++) {
 		struct xen_blkif_ring *ring = &blkif->rings[r];
 
@@ -175,6 +183,7 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
 	blkif->domid = domid;
 	atomic_set(&blkif->refcnt, 1);
 	init_completion(&blkif->drain_complete);
+	rwlock_init(&blkif->rings_lock);
 
 	/*
 	 * Because freeing back to the cache may be deferred, it is not
@@ -269,6 +278,7 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif)
 	struct pending_req *req, *n;
 	unsigned int j, r;
 	bool busy = false;
+	struct xen_blkif_ring *rings;
 
 	for (r = 0; r < blkif->nr_rings; r++) {
 		struct xen_blkif_ring *ring = &blkif->rings[r];
@@ -335,10 +345,16 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif)
 	 * blkif->rings was allocated in connect_ring, so we should free it in
 	 * here.
 	 */
-	kfree(blkif->rings);
+	write_lock(&blkif->rings_lock);
+
+	rings = blkif->rings;
 	blkif->rings = NULL;
 	blkif->nr_rings = 0;
 
+	write_unlock(&blkif->rings_lock);
+
+	kfree(rings);
+
 	return 0;
 }
 
@@ -386,6 +402,7 @@ void xen_blkif_interface_fini(void)
 		unsigned int i;						\
 		unsigned long long result = 0;				\
 									\
+		read_lock(&blkif->rings_lock);				\
 		if (!blkif->rings)				\
 			goto out;					\
 									\
@@ -396,6 +413,7 @@ void xen_blkif_interface_fini(void)
 		}							\
 									\
 out:									\
+		read_unlock(&blkif->rings_lock);			\
 		return sprintf(buf, format, result);			\
 	}								\
 	static DEVICE_ATTR(name, 0444, show_##name, NULL)
@@ -1110,8 +1128,7 @@ static int connect_ring(struct backend_info *be)
 				requested_num_queues, xenblk_max_queues);
 		return -ENOSYS;
 	}
-	blkif->nr_rings = requested_num_queues;
-	if (xen_blkif_alloc_rings(blkif))
+	if (xen_blkif_alloc_rings(blkif, requested_num_queues))
 		return -ENOMEM;
 
 	pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename,
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 09fc4bc0622e..18c236047408 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -811,8 +811,6 @@ void xenvif_disconnect_data(struct xenvif *vif)
 
 		xenvif_disconnect_queue(queue);
 	}
-
-	xenvif_mcast_addr_list_free(vif);
 }
 
 void xenvif_disconnect_ctrl(struct xenvif *vif)
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index c47e327039a0..1d03fe6cad9c 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -267,6 +267,8 @@ static void backend_disconnect(struct backend_info *be)
 		vif->num_queues = 0;
 		synchronize_net();
 
+		xenvif_mcast_addr_list_free(vif);
+
 		for (queue_index = 0; queue_index < num_queues; ++queue_index)
 			xenvif_deinit_queue(&vif->queues[queue_index]);
 
@@ -837,6 +839,7 @@ static void connect(struct backend_info *be)
 err:
 	if (be->vif->num_queues > 0)
 		xenvif_disconnect_data(be->vif); /* Clean up existing queues */
+	synchronize_net();
 	for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
 		xenvif_deinit_queue(&be->vif->queues[queue_index]);
 	vfree(be->vif->queues);