1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2020 Intel Corporation
4 */
5
6#include <linux/mm.h>
7#include <linux/pagemap.h>
8#include <linux/shmem_fs.h>
9
10#include "gem/i915_gem_object.h"
11#include "shmem_utils.h"
12
13struct file *shmem_create_from_data(const char *name, void *data, size_t len)
14{
15	struct file *file;
16	int err;
17
18	file = shmem_file_setup(name, PAGE_ALIGN(len), VM_NORESERVE);
19	if (IS_ERR(file))
20		return file;
21
22	err = shmem_write(file, 0, data, len);
23	if (err) {
24		fput(file);
25		return ERR_PTR(err);
26	}
27
28	return file;
29}
30
31struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
32{
33	struct file *file;
34	void *ptr;
35
36	if (obj->ops == &i915_gem_shmem_ops) {
37		file = obj->base.filp;
38		atomic_long_inc(&file->f_count);
39		return file;
40	}
41
42	ptr = i915_gem_object_pin_map(obj, I915_MAP_WB);
43	if (IS_ERR(ptr))
44		return ERR_CAST(ptr);
45
46	file = shmem_create_from_data("", ptr, obj->base.size);
47	i915_gem_object_unpin_map(obj);
48
49	return file;
50}
51
52void *shmem_pin_map(struct file *file)
53{
54	struct page **pages;
55	size_t n_pages, i;
56	void *vaddr;
57
58	n_pages = file->f_mapping->host->i_size >> PAGE_SHIFT;
59	pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
60	if (!pages)
61		return NULL;
62
63	for (i = 0; i < n_pages; i++) {
64		pages[i] = shmem_read_mapping_page_gfp(file->f_mapping, i,
65						       GFP_KERNEL);
66		if (IS_ERR(pages[i]))
67			goto err_page;
68	}
69
70	vaddr = vmap(pages, n_pages, VM_MAP_PUT_PAGES, PAGE_KERNEL);
71	if (!vaddr)
72		goto err_page;
73	mapping_set_unevictable(file->f_mapping);
74	return vaddr;
75err_page:
76	while (i--)
77		put_page(pages[i]);
78	kvfree(pages);
79	return NULL;
80}
81
82void shmem_unpin_map(struct file *file, void *ptr)
83{
84	mapping_clear_unevictable(file->f_mapping);
85	vfree(ptr);
86}
87
88static int __shmem_rw(struct file *file, loff_t off,
89		      void *ptr, size_t len,
90		      bool write)
91{
92	unsigned long pfn;
93
94	for (pfn = off >> PAGE_SHIFT; len; pfn++) {
95		unsigned int this =
96			min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
97		struct page *page;
98		void *vaddr;
99
100		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
101						   GFP_KERNEL);
102		if (IS_ERR(page))
103			return PTR_ERR(page);
104
105		vaddr = kmap(page);
106		if (write) {
107			memcpy(vaddr + offset_in_page(off), ptr, this);
108			set_page_dirty(page);
109		} else {
110			memcpy(ptr, vaddr + offset_in_page(off), this);
111		}
112		mark_page_accessed(page);
113		kunmap(page);
114		put_page(page);
115
116		len -= this;
117		ptr += this;
118		off = 0;
119	}
120
121	return 0;
122}
123
124int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
125{
126	return __shmem_rw(file, off, dst, len, false);
127}
128
129int shmem_write(struct file *file, loff_t off, void *src, size_t len)
130{
131	return __shmem_rw(file, off, src, len, true);
132}
133
134#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
135#include "st_shmem_utils.c"
136#endif
137