1 files changed, 45 insertions, 22 deletions

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 0f6cd44fff29..8d3cff42bdbb 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1611,16 +1611,16 @@ static ssize_t target_cpu_show(struct vmbus_channel *channel, char *buf)
 {
 	return sprintf(buf, "%u\n", channel->target_cpu);
 }
-static ssize_t target_cpu_store(struct vmbus_channel *channel,
-				const char *buf, size_t count)
+
+int vmbus_channel_set_cpu(struct vmbus_channel *channel, u32 target_cpu)
 {
-	u32 target_cpu, origin_cpu;
-	ssize_t ret = count;
+	u32 origin_cpu;
+	int ret = 0;
 
-	if (vmbus_proto_version < VERSION_WIN10_V4_1)
-		return -EIO;
+	lockdep_assert_cpus_held();
+	lockdep_assert_held(&vmbus_connection.channel_mutex);
 
-	if (sscanf(buf, "%uu", &target_cpu) != 1)
+	if (vmbus_proto_version < VERSION_WIN10_V4_1)
 		return -EIO;
 
 	/* Validate target_cpu for the cpumask_test_cpu() operation below. */
@@ -1630,22 +1630,17 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel,
 	if (!cpumask_test_cpu(target_cpu, housekeeping_cpumask(HK_TYPE_MANAGED_IRQ)))
 		return -EINVAL;
 
-	/* No CPUs should come up or down during this. */
-	cpus_read_lock();
-
-	if (!cpu_online(target_cpu)) {
-		cpus_read_unlock();
+	if (!cpu_online(target_cpu))
 		return -EINVAL;
-	}
 
 	/*
-	 * Synchronizes target_cpu_store() and channel closure:
+	 * Synchronizes vmbus_channel_set_cpu() and channel closure:
 	 *
 	 * { Initially: state = CHANNEL_OPENED }
 	 *
 	 * CPU1				CPU2
 	 *
-	 * [target_cpu_store()]		[vmbus_disconnect_ring()]
+	 * [vmbus_channel_set_cpu()]	[vmbus_disconnect_ring()]
 	 *
 	 * LOCK channel_mutex		LOCK channel_mutex
 	 * LOAD r1 = state		LOAD r2 = state
@@ -1660,7 +1655,6 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel,
 	 * Note.  The host processes the channel messages "sequentially", in
 	 * the order in which they are received on a per-partition basis.
 	 */
-	mutex_lock(&vmbus_connection.channel_mutex);
 
 	/*
 	 * Hyper-V will ignore MODIFYCHANNEL messages for "non-open" channels;
@@ -1668,17 +1662,17 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel,
 	 */
 	if (channel->state != CHANNEL_OPENED_STATE) {
 		ret = -EIO;
-		goto cpu_store_unlock;
+		goto end;
 	}
 
 	origin_cpu = channel->target_cpu;
 	if (target_cpu == origin_cpu)
-		goto cpu_store_unlock;
+		goto end;
 
 	if (vmbus_send_modifychannel(channel,
 				     hv_cpu_number_to_vp_number(target_cpu))) {
 		ret = -EIO;
-		goto cpu_store_unlock;
+		goto end;
 	}
 
 	/*
@@ -1708,10 +1702,26 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel,
 				origin_cpu, target_cpu);
 	}
 
-cpu_store_unlock:
+end:
+	return ret;
+}
+
+static ssize_t target_cpu_store(struct vmbus_channel *channel,
+				const char *buf, size_t count)
+{
+	u32 target_cpu;
+	ssize_t ret;
+
+	if (sscanf(buf, "%uu", &target_cpu) != 1)
+		return -EIO;
+
+	cpus_read_lock();
+	mutex_lock(&vmbus_connection.channel_mutex);
+	ret = vmbus_channel_set_cpu(channel, target_cpu);
 	mutex_unlock(&vmbus_connection.channel_mutex);
 	cpus_read_unlock();
-	return ret;
+
+	return ret ?: count;
 }
 static VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store);
 
@@ -2262,12 +2272,25 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size)
 	struct resource *iter;
 
 	mutex_lock(&hyperv_mmio_lock);
+
+	/*
+	 * If all bytes of the MMIO range to be released are within the
+	 * special case fb_mmio shadow region, skip releasing the shadow
+	 * region since no corresponding __request_region() was done
+	 * in vmbus_allocate_mmio().
+	 */
+	if (fb_mmio && start >= fb_mmio->start &&
+	    (start + size - 1 <= fb_mmio->end))
+		goto skip_shadow_release;
+
 	for (iter = hyperv_mmio; iter; iter = iter->sibling) {
 		if ((iter->start >= start + size) || (iter->end <= start))
 			continue;
 
 		__release_region(iter, start, size);
 	}
+
+skip_shadow_release:
 	release_mem_region(start, size);
 	mutex_unlock(&hyperv_mmio_lock);
 
@@ -2646,7 +2669,7 @@ static int __init hv_acpi_init(void)
 	if (!hv_is_hyperv_initialized())
 		return -ENODEV;
 
-	if (hv_root_partition && !hv_nested)
+	if (hv_root_partition() && !hv_nested)
 		return 0;
 
 	/*