diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 5163c8f918cb23a13f8cbe32e64db5d35a512317..5497f7fc44d04c0287a6c51d968a7df0165a37c3 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1413,8 +1413,14 @@ static ssize_t hot_remove_store(struct class *class,
 	return ret ? ret : count;
 }
 
+/*
+ * NOTE: hot_add attribute is not the usual read-only sysfs attribute. In a
+ * sense that reading from this file does alter the state of your system -- it
+ * creates a new un-initialized zram device and returns back this device's
+ * device_id (or an error code if it fails to create a new device).
+ */
 static struct class_attribute zram_control_class_attrs[] = {
-	__ATTR_RO(hot_add),
+	__ATTR(hot_add, 0400, hot_add_show, NULL),
 	__ATTR_WO(hot_remove),
 	__ATTR_NULL,
 };
diff --git a/kernel/kcov.c b/kernel/kcov.c
index 30e6d05aa5a9f726422c7968dabbff5e1c590c2a..3cbb0c879705f7a29f1d5bfad58551c098e69432 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -7,6 +7,7 @@
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/printk.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/vmalloc.h>
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 8e6d552c40ddfc7fa745a8a8acf34ee17f02bc3d..0d1d23ea7925b36a21c9aedc3dabfa5d064dd591 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -30,7 +30,6 @@
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <linux/kmemleak.h>
-#include <linux/notifier.h>
 #include <linux/cpu.h>
 #include <linux/string.h>
 #include <linux/bitops.h>
diff --git a/tools/testing/radix-tree/linux/cpu.h b/tools/testing/radix-tree/linux/cpu.h
index 7cf412103205b1f49b29350fdd93d4f496307e16..a45530d7810748c41f5458cc8e70244efead808c 100644
--- a/tools/testing/radix-tree/linux/cpu.h
+++ b/tools/testing/radix-tree/linux/cpu.h
@@ -1,21 +1 @@
-
-#define hotcpu_notifier(a, b)
-
-#define CPU_ONLINE		0x0002 /* CPU (unsigned)v is up */
-#define CPU_UP_PREPARE		0x0003 /* CPU (unsigned)v coming up */
-#define CPU_UP_CANCELED		0x0004 /* CPU (unsigned)v NOT coming up */
-#define CPU_DOWN_PREPARE	0x0005 /* CPU (unsigned)v going down */
-#define CPU_DOWN_FAILED		0x0006 /* CPU (unsigned)v NOT going down */
-#define CPU_DEAD		0x0007 /* CPU (unsigned)v dead */
-#define CPU_POST_DEAD		0x0009 /* CPU (unsigned)v dead, cpu_hotplug
-					* lock is dropped */
-#define CPU_BROKEN		0x000C /* CPU (unsigned)v did not die properly,
-					* perhaps due to preemption. */
-#define CPU_TASKS_FROZEN	0x0010
-
-#define CPU_ONLINE_FROZEN	(CPU_ONLINE | CPU_TASKS_FROZEN)
-#define CPU_UP_PREPARE_FROZEN	(CPU_UP_PREPARE | CPU_TASKS_FROZEN)
-#define CPU_UP_CANCELED_FROZEN  (CPU_UP_CANCELED | CPU_TASKS_FROZEN)
-#define CPU_DOWN_PREPARE_FROZEN (CPU_DOWN_PREPARE | CPU_TASKS_FROZEN)
-#define CPU_DOWN_FAILED_FROZEN  (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
-#define CPU_DEAD_FROZEN		(CPU_DEAD | CPU_TASKS_FROZEN)
+#define cpuhp_setup_state_nocalls(a, b, c, d)	(0)
diff --git a/tools/testing/radix-tree/linux/notifier.h b/tools/testing/radix-tree/linux/notifier.h
deleted file mode 100644
index 70e4797d5a46f22eb66075d94eeda1a5f8aa9b10..0000000000000000000000000000000000000000
--- a/tools/testing/radix-tree/linux/notifier.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#ifndef _NOTIFIER_H
-#define _NOTIFIER_H
-
-struct notifier_block;
-
-#define NOTIFY_OK              0x0001          /* Suits me */
-
-#endif