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Commit 8325330b authored by Sasha Levin's avatar Sasha Levin Committed by Linus Torvalds
Browse files

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: default avatarSasha Levin <sasha.levin@oracle.com>
Acked-by: default avatarJoonsoo 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: default avatarMichal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 26b02a1f

mm/cma_debug.c

+58 −0
Original line number Diff line number Diff line
@@ -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 @@ static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem) 
	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 @@ static void cma_debugfs_add_one(struct cma *cma, int idx) 
	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,