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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
52static size_t shmem_npte(struct file *file)
53{
54 return file->f_mapping->host->i_size >> PAGE_SHIFT;
55}
56
57static void __shmem_unpin_map(struct file *file, void *ptr, size_t n_pte)
58{
59 unsigned long pfn;
60
61 vunmap(ptr);
62
63 for (pfn = 0; pfn < n_pte; pfn++) {
64 struct page *page;
65
66 page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
67 GFP_KERNEL);
68 if (!WARN_ON(IS_ERR(page))) {
69 put_page(page);
70 put_page(page);
71 }
72 }
73}
74
75void *shmem_pin_map(struct file *file)
76{
77 const size_t n_pte = shmem_npte(file);
78 pte_t *stack[32], **ptes, **mem;
79 struct vm_struct *area;
80 unsigned long pfn;
81
82 mem = stack;
83 if (n_pte > ARRAY_SIZE(stack)) {
84 mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
85 if (!mem)
86 return NULL;
87 }
88
89 area = alloc_vm_area(n_pte << PAGE_SHIFT, mem);
90 if (!area) {
91 if (mem != stack)
92 kvfree(mem);
93 return NULL;
94 }
95
96 ptes = mem;
97 for (pfn = 0; pfn < n_pte; pfn++) {
98 struct page *page;
99
100 page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
101 GFP_KERNEL);
102 if (IS_ERR(page))
103 goto err_page;
104
105 **ptes++ = mk_pte(page, PAGE_KERNEL);
106 }
107
108 if (mem != stack)
109 kvfree(mem);
110
111 mapping_set_unevictable(file->f_mapping);
112 return area->addr;
113
114err_page:
115 if (mem != stack)
116 kvfree(mem);
117
118 __shmem_unpin_map(file, area->addr, pfn);
119 return NULL;
120}
121
122void shmem_unpin_map(struct file *file, void *ptr)
123{
124 mapping_clear_unevictable(file->f_mapping);
125 __shmem_unpin_map(file, ptr, shmem_npte(file));
126}
127
128static int __shmem_rw(struct file *file, loff_t off,
129 void *ptr, size_t len,
130 bool write)
131{
132 unsigned long pfn;
133
134 for (pfn = off >> PAGE_SHIFT; len; pfn++) {
135 unsigned int this =
136 min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
137 struct page *page;
138 void *vaddr;
139
140 page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
141 GFP_KERNEL);
142 if (IS_ERR(page))
143 return PTR_ERR(page);
144
145 vaddr = kmap(page);
146 if (write)
147 memcpy(vaddr + offset_in_page(off), ptr, this);
148 else
149 memcpy(ptr, vaddr + offset_in_page(off), this);
150 kunmap(page);
151 put_page(page);
152
153 len -= this;
154 ptr += this;
155 off = 0;
156 }
157
158 return 0;
159}
160
161int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
162{
163 return __shmem_rw(file, off, dst, len, false);
164}
165
166int shmem_write(struct file *file, loff_t off, void *src, size_t len)
167{
168 return __shmem_rw(file, off, src, len, true);
169}
170
171#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
172#include "st_shmem_utils.c"
173#endif
174
