1 files changed, 53 insertions, 0 deletions
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index c52a6b834f08..3b567838b905 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -26,6 +26,7 @@
 #include <linux/poison.h>
 #include <linux/initrd.h>
 #include <linux/export.h>
+#include <linux/cma.h>
 #include <linux/gfp.h>
 #include <linux/memblock.h>
 #include <asm/processor.h>
@@ -167,6 +168,58 @@ unsigned long memory_block_size_bytes(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
+
+#ifdef CONFIG_CMA
+
+/* Prevent memory blocks which contain cma regions from going offline */
+
+struct s390_cma_mem_data {
+	unsigned long start;
+	unsigned long end;
+};
+
+static int s390_cma_check_range(struct cma *cma, void *data)
+{
+	struct s390_cma_mem_data *mem_data;
+	unsigned long start, end;
+
+	mem_data = data;
+	start = cma_get_base(cma);
+	end = start + cma_get_size(cma);
+	if (end < mem_data->start)
+		return 0;
+	if (start >= mem_data->end)
+		return 0;
+	return -EBUSY;
+}
+
+static int s390_cma_mem_notifier(struct notifier_block *nb,
+				 unsigned long action, void *data)
+{
+	struct s390_cma_mem_data mem_data;
+	struct memory_notify *arg;
+	int rc = 0;
+
+	arg = data;
+	mem_data.start = arg->start_pfn << PAGE_SHIFT;
+	mem_data.end = mem_data.start + (arg->nr_pages << PAGE_SHIFT);
+	if (action == MEM_GOING_OFFLINE)
+		rc = cma_for_each_area(s390_cma_check_range, &mem_data);
+	return notifier_from_errno(rc);
+}
+
+static struct notifier_block s390_cma_mem_nb = {
+	.notifier_call = s390_cma_mem_notifier,
+};
+
+static int __init s390_cma_mem_init(void)
+{
+	return register_memory_notifier(&s390_cma_mem_nb);
+}
+device_initcall(s390_cma_mem_init);
+
+#endif /* CONFIG_CMA */
+
 int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock)
 {
 	unsigned long start_pfn = PFN_DOWN(start);