mm: cma: release trigger
Provides a userspace interface to trigger a CMA release.
Usage:
echo [pages] > free
This would provide testing/fuzzing access to the CMA release paths.
[akpm@linux-foundation.org: coding-style fixes]
[mhocko@suse.cz: fix build]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/cma_debug.c b/mm/cma_debug.c
index f3baa41..ae41fae 100644
--- a/mm/cma_debug.c
+++ b/mm/cma_debug.c
@@ -10,6 +10,7 @@
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/slab.h>
+#include <linux/mm_types.h>
#include "cma.h"
@@ -39,6 +40,60 @@
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;
@@ -85,6 +140,9 @@
debugfs_create_file("alloc", S_IWUSR, cma_debugfs_root, cma,
&cma_alloc_fops);
+ debugfs_create_file("free", S_IWUSR, cma_debugfs_root, cma,
+ &cma_free_fops);
+
debugfs_create_file("base_pfn", S_IRUGO, tmp,
&cma->base_pfn, &cma_debugfs_fops);
debugfs_create_file("count", S_IRUGO, tmp,