xref: /src/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gemfs.c

/*	$NetBSD: i915_gemfs.c,v 1.2 2021/12/18 23:45:30 riastradh Exp $	*/

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright  2017 Intel Corporation
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: i915_gemfs.c,v 1.2 2021/12/18 23:45:30 riastradh Exp $");

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>

#include "i915_drv.h"
#include "i915_gemfs.h"

int i915_gemfs_init(struct drm_i915_private *i915)
{
	struct file_system_type *type;
	struct vfsmount *gemfs;

	type = get_fs_type("tmpfs");
	if (!type)
		return -ENODEV;

	/*
	 * By creating our own shmemfs mountpoint, we can pass in
	 * mount flags that better match our usecase.
	 *
	 * One example, although it is probably better with a per-file
	 * control, is selecting huge page allocations ("huge=within_size").
	 * Currently unused due to bandwidth issues (slow reads) on Broadwell+.
	 */

	gemfs = kern_mount(type);
	if (IS_ERR(gemfs))
		return PTR_ERR(gemfs);

	i915->mm.gemfs = gemfs;

	return 0;
}

void i915_gemfs_fini(struct drm_i915_private *i915)
{
	kern_unmount(i915->mm.gemfs);
}