Commit e1fc39a9 authored by Dmitry Osipenko's avatar Dmitry Osipenko
Browse files

drm/shmem-helper: Use refcount_t for vmap_use_count 



Use refcount_t helper for vmap_use_count to make refcounting consistent
with pages_use_count and pages_pin_count that use refcount_t. This also
makes vmapping to benefit from the refcount_t's overflow checks.

Acked-by: default avatarMaxime Ripard <mripard@kernel.org>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Suggested-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Acked-by: default avatarThomas Zimmermann <tzimmermann@suse.d>
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250322212608.40511-11-dmitry.osipenko@collabora.com
parent 0271cc48

drivers/gpu/drm/drm_gem_shmem_helper.c

+12 −16
Original line number Diff line number Diff line
@@ -165,7 +165,7 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) 
	} else {

		dma_resv_lock(shmem->base.resv, NULL);



		drm_WARN_ON(obj->dev, shmem->vmap_use_count);

		drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count));



		if (shmem->sgt) {

			dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
@@ -355,23 +355,25 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, 


		dma_resv_assert_held(shmem->base.resv);



		if (shmem->vmap_use_count++ > 0) {

		if (refcount_inc_not_zero(&shmem->vmap_use_count)) {

			iosys_map_set_vaddr(map, shmem->vaddr);

			return 0;

		}



		ret = drm_gem_shmem_pin_locked(shmem);

		if (ret)

			goto err_zero_use;

			return ret;



		if (shmem->map_wc)

			prot = pgprot_writecombine(prot);

		shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,

				    VM_MAP, prot);

		if (!shmem->vaddr)

		if (!shmem->vaddr) {

			ret = -ENOMEM;

		else

		} else {

			iosys_map_set_vaddr(map, shmem->vaddr);

			refcount_set(&shmem->vmap_use_count, 1);

		}

	}



	if (ret) {
@@ -384,8 +386,6 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, 
err_put_pages:

	if (!drm_gem_is_imported(obj))

		drm_gem_shmem_unpin_locked(shmem);

err_zero_use:

	shmem->vmap_use_count = 0;



	return ret;

}
@@ -413,15 +413,11 @@ void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, 
	} else {

		dma_resv_assert_held(shmem->base.resv);



		if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count))

			return;



		if (--shmem->vmap_use_count > 0)

			return;



		if (refcount_dec_and_test(&shmem->vmap_use_count)) {

			vunmap(shmem->vaddr);

			drm_gem_shmem_unpin_locked(shmem);

		}

	}



	shmem->vaddr = NULL;

}
@@ -672,7 +668,7 @@ void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem, 


	drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count));

	drm_printf_indent(p, indent, "pages_use_count=%u\n", refcount_read(&shmem->pages_use_count));

	drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);

	drm_printf_indent(p, indent, "vmap_use_count=%u\n", refcount_read(&shmem->vmap_use_count));

	drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);

}

EXPORT_SYMBOL_GPL(drm_gem_shmem_print_info);

drivers/gpu/drm/tests/drm_gem_shmem_test.c

+3 −3
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ static void drm_gem_shmem_test_vmap(struct kunit *test) 
	shmem = drm_gem_shmem_create(drm_dev, TEST_SIZE);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);

	KUNIT_EXPECT_NULL(test, shmem->vaddr);

	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 0);

	KUNIT_EXPECT_EQ(test, refcount_read(&shmem->vmap_use_count), 0);



	ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);

	KUNIT_ASSERT_EQ(test, ret, 0);
@@ -177,7 +177,7 @@ static void drm_gem_shmem_test_vmap(struct kunit *test) 
	KUNIT_ASSERT_EQ(test, ret, 0);

	KUNIT_ASSERT_NOT_NULL(test, shmem->vaddr);

	KUNIT_ASSERT_FALSE(test, iosys_map_is_null(&map));

	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 1);

	KUNIT_EXPECT_EQ(test, refcount_read(&shmem->vmap_use_count), 1);



	iosys_map_memset(&map, 0, TEST_BYTE, TEST_SIZE);

	for (i = 0; i < TEST_SIZE; i++)
@@ -185,7 +185,7 @@ static void drm_gem_shmem_test_vmap(struct kunit *test) 


	drm_gem_shmem_vunmap_locked(shmem, &map);

	KUNIT_EXPECT_NULL(test, shmem->vaddr);

	KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 0);

	KUNIT_EXPECT_EQ(test, refcount_read(&shmem->vmap_use_count), 0);

}



/*

include/drm/drm_gem_shmem_helper.h

+1 −1
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ struct drm_gem_shmem_object { 
	 * Reference count on the virtual address.

	 * The address are un-mapped when the count reaches zero.

	 */

	unsigned int vmap_use_count;

	refcount_t vmap_use_count;



	/**

	 * @pages_mark_dirty_on_put: