Commit 26b02a1f authored by Sasha Levin's avatar Sasha Levin Committed by Linus Torvalds

mm: cma: allocation trigger

Provides a userspace interface to trigger a CMA allocation.


        echo [pages] > alloc

This would provide testing/fuzzing access to the CMA allocation paths.
Signed-off-by: default avatarSasha Levin <>
Acked-by: default avatarJoonsoo Kim <>
Cc: Marek Szyprowski <>
Cc: Laura Abbott <>
Cc: Konrad Rzeszutek Wilk <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 28b24c1f
......@@ -123,6 +123,12 @@ static int __init cma_activate_area(struct cma *cma)
} while (--i);
return 0;
......@@ -7,6 +7,10 @@ struct cma {
unsigned long *bitmap;
unsigned int order_per_bit; /* Order of pages represented by one bit */
struct mutex lock;
struct hlist_head mem_head;
spinlock_t mem_head_lock;
extern struct cma cma_areas[MAX_CMA_AREAS];
......@@ -7,9 +7,18 @@
#include <linux/debugfs.h>
#include <linux/cma.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/slab.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)
......@@ -23,6 +32,46 @@ static int cma_debugfs_get(void *data, u64 *val)
DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
hlist_add_head(&mem->node, &cma->mem_head);
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, CONFIG_CMA_ALIGNMENT);
if (!p) {
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;
......@@ -33,12 +82,15 @@ static void cma_debugfs_add_one(struct cma *cma, int idx)
tmp = debugfs_create_dir(name, cma_debugfs_root);
debugfs_create_file("alloc", S_IWUSR, cma_debugfs_root, cma,
debugfs_create_file("base_pfn", S_IRUGO, tmp,
&cma->base_pfn, &cma_debugfs_fops);
debugfs_create_file("count", S_IRUGO, tmp,
&cma->count, &cma_debugfs_fops);
debugfs_create_file("order_per_bit", S_IRUGO, tmp,
&cma->order_per_bit, &cma_debugfs_fops);
&cma->order_per_bit, &cma_debugfs_fops);
u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s);
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