v4.19.13 snapshot.
diff --git a/mm/cma_debug.c b/mm/cma_debug.c
new file mode 100644
index 0000000..ad6723e
--- /dev/null
+++ b/mm/cma_debug.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CMA DebugFS Interface
+ *
+ * Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com>
+ */
+
+
+#include <linux/debugfs.h>
+#include <linux/cma.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mm_types.h>
+
+#include "cma.h"
+
+struct cma_mem {
+ struct hlist_node node;
+ struct page *p;
+ unsigned long n;
+};
+
+static struct dentry *cma_debugfs_root;
+
+static int cma_debugfs_get(void *data, u64 *val)
+{
+ unsigned long *p = data;
+
+ *val = *p;
+
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
+
+static int cma_used_get(void *data, u64 *val)
+{
+ struct cma *cma = data;
+ unsigned long used;
+
+ mutex_lock(&cma->lock);
+ /* pages counter is smaller than sizeof(int) */
+ used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma));
+ mutex_unlock(&cma->lock);
+ *val = (u64)used << cma->order_per_bit;
+
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
+
+static int cma_maxchunk_get(void *data, u64 *val)
+{
+ struct cma *cma = data;
+ unsigned long maxchunk = 0;
+ unsigned long start, end = 0;
+ unsigned long bitmap_maxno = cma_bitmap_maxno(cma);
+
+ mutex_lock(&cma->lock);
+ for (;;) {
+ start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end);
+ if (start >= cma->count)
+ break;
+ end = find_next_bit(cma->bitmap, bitmap_maxno, start);
+ maxchunk = max(end - start, maxchunk);
+ }
+ mutex_unlock(&cma->lock);
+ *val = (u64)maxchunk << cma->order_per_bit;
+
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
+
+static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
+{
+ spin_lock(&cma->mem_head_lock);
+ hlist_add_head(&mem->node, &cma->mem_head);
+ spin_unlock(&cma->mem_head_lock);
+}
+
+static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
+{
+ struct cma_mem *mem = NULL;
+
+ spin_lock(&cma->mem_head_lock);
+ if (!hlist_empty(&cma->mem_head)) {
+ mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
+ hlist_del_init(&mem->node);
+ }
+ spin_unlock(&cma->mem_head_lock);
+
+ return mem;
+}
+
+static int cma_free_mem(struct cma *cma, int count)
+{
+ struct cma_mem *mem = NULL;
+
+ while (count) {
+ mem = cma_get_entry_from_list(cma);
+ if (mem == NULL)
+ return 0;
+
+ if (mem->n <= count) {
+ cma_release(cma, mem->p, mem->n);
+ count -= mem->n;
+ kfree(mem);
+ } else if (cma->order_per_bit == 0) {
+ cma_release(cma, mem->p, count);
+ mem->p += count;
+ mem->n -= count;
+ count = 0;
+ cma_add_to_cma_mem_list(cma, mem);
+ } else {
+ pr_debug("cma: cannot release partial block when order_per_bit != 0\n");
+ cma_add_to_cma_mem_list(cma, mem);
+ break;
+ }
+ }
+
+ return 0;
+
+}
+
+static int cma_free_write(void *data, u64 val)
+{
+ int pages = val;
+ struct cma *cma = data;
+
+ return cma_free_mem(cma, pages);
+}
+DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
+
+static int cma_alloc_mem(struct cma *cma, int count)
+{
+ struct cma_mem *mem;
+ struct page *p;
+
+ mem = kzalloc(sizeof(*mem), GFP_KERNEL);
+ if (!mem)
+ return -ENOMEM;
+
+ p = cma_alloc(cma, count, 0, false);
+ if (!p) {
+ kfree(mem);
+ return -ENOMEM;
+ }
+
+ mem->p = p;
+ mem->n = count;
+
+ cma_add_to_cma_mem_list(cma, mem);
+
+ return 0;
+}
+
+static int cma_alloc_write(void *data, u64 val)
+{
+ int pages = val;
+ struct cma *cma = data;
+
+ return cma_alloc_mem(cma, pages);
+}
+DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
+
+static void cma_debugfs_add_one(struct cma *cma, int idx)
+{
+ struct dentry *tmp;
+ char name[16];
+ int u32s;
+
+ scnprintf(name, sizeof(name), "cma-%s", cma->name);
+
+ tmp = debugfs_create_dir(name, cma_debugfs_root);
+
+ debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops);
+ debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops);
+ debugfs_create_file("base_pfn", 0444, tmp,
+ &cma->base_pfn, &cma_debugfs_fops);
+ debugfs_create_file("count", 0444, tmp, &cma->count, &cma_debugfs_fops);
+ debugfs_create_file("order_per_bit", 0444, tmp,
+ &cma->order_per_bit, &cma_debugfs_fops);
+ debugfs_create_file("used", 0444, tmp, cma, &cma_used_fops);
+ debugfs_create_file("maxchunk", 0444, tmp, cma, &cma_maxchunk_fops);
+
+ u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
+ debugfs_create_u32_array("bitmap", 0444, tmp, (u32 *)cma->bitmap, u32s);
+}
+
+static int __init cma_debugfs_init(void)
+{
+ int i;
+
+ cma_debugfs_root = debugfs_create_dir("cma", NULL);
+ if (!cma_debugfs_root)
+ return -ENOMEM;
+
+ for (i = 0; i < cma_area_count; i++)
+ cma_debugfs_add_one(&cma_areas[i], i);
+
+ return 0;
+}
+late_initcall(cma_debugfs_init);