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12#include <linux/module.h>
13#include <linux/fs.h>
14#include <linux/mm.h>
15#include <linux/pagemap.h>
16#include <linux/highmem.h>
17#include <linux/init.h>
18#include <linux/string.h>
19#include <linux/backing-dev.h>
20#include <linux/ramfs.h>
21#include <linux/pagevec.h>
22#include <linux/mman.h>
23#include <linux/sched.h>
24#include <linux/slab.h>
25
26#include <linux/uaccess.h>
27#include "internal.h"
28
29static int ramfs_nommu_setattr(struct dentry *, struct iattr *);
30static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
31 unsigned long addr,
32 unsigned long len,
33 unsigned long pgoff,
34 unsigned long flags);
35static int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma);
36
37static unsigned ramfs_mmap_capabilities(struct file *file)
38{
39 return NOMMU_MAP_DIRECT | NOMMU_MAP_COPY | NOMMU_MAP_READ |
40 NOMMU_MAP_WRITE | NOMMU_MAP_EXEC;
41}
42
43const struct file_operations ramfs_file_operations = {
44 .mmap_capabilities = ramfs_mmap_capabilities,
45 .mmap = ramfs_nommu_mmap,
46 .get_unmapped_area = ramfs_nommu_get_unmapped_area,
47 .read_iter = generic_file_read_iter,
48 .write_iter = generic_file_write_iter,
49 .fsync = noop_fsync,
50 .splice_read = generic_file_splice_read,
51 .splice_write = iter_file_splice_write,
52 .llseek = generic_file_llseek,
53};
54
55const struct inode_operations ramfs_file_inode_operations = {
56 .setattr = ramfs_nommu_setattr,
57 .getattr = simple_getattr,
58};
59
60
61
62
63
64
65
66int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
67{
68 unsigned long npages, xpages, loop;
69 struct page *pages;
70 unsigned order;
71 void *data;
72 int ret;
73 gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
74
75
76 order = get_order(newsize);
77 if (unlikely(order >= MAX_ORDER))
78 return -EFBIG;
79
80 ret = inode_newsize_ok(inode, newsize);
81 if (ret)
82 return ret;
83
84 i_size_write(inode, newsize);
85
86
87
88 pages = alloc_pages(gfp, order);
89 if (!pages)
90 return -ENOMEM;
91
92
93 xpages = 1UL << order;
94 npages = (newsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
95
96 split_page(pages, order);
97
98
99 for (loop = npages; loop < xpages; loop++)
100 __free_page(pages + loop);
101
102
103 newsize = PAGE_SIZE * npages;
104 data = page_address(pages);
105 memset(data, 0, newsize);
106
107
108 for (loop = 0; loop < npages; loop++) {
109 struct page *page = pages + loop;
110
111 ret = add_to_page_cache_lru(page, inode->i_mapping, loop,
112 gfp);
113 if (ret < 0)
114 goto add_error;
115
116
117 SetPageDirty(page);
118 SetPageUptodate(page);
119
120 unlock_page(page);
121 put_page(page);
122 }
123
124 return 0;
125
126add_error:
127 while (loop < npages)
128 __free_page(pages + loop++);
129 return ret;
130}
131
132
133
134
135
136static int ramfs_nommu_resize(struct inode *inode, loff_t newsize, loff_t size)
137{
138 int ret;
139
140
141
142 if (size == 0) {
143 if (unlikely(newsize >> 32))
144 return -EFBIG;
145
146 return ramfs_nommu_expand_for_mapping(inode, newsize);
147 }
148
149
150 if (newsize < size) {
151 ret = nommu_shrink_inode_mappings(inode, size, newsize);
152 if (ret < 0)
153 return ret;
154 }
155
156 truncate_setsize(inode, newsize);
157 return 0;
158}
159
160
161
162
163
164
165static int ramfs_nommu_setattr(struct dentry *dentry, struct iattr *ia)
166{
167 struct inode *inode = d_inode(dentry);
168 unsigned int old_ia_valid = ia->ia_valid;
169 int ret = 0;
170
171
172 ret = setattr_prepare(dentry, ia);
173 if (ret)
174 return ret;
175
176
177 if (ia->ia_valid & ATTR_SIZE) {
178 loff_t size = inode->i_size;
179
180 if (ia->ia_size != size) {
181 ret = ramfs_nommu_resize(inode, ia->ia_size, size);
182 if (ret < 0 || ia->ia_valid == ATTR_SIZE)
183 goto out;
184 } else {
185
186
187
188 ia->ia_valid |= ATTR_MTIME|ATTR_CTIME;
189 }
190 }
191
192 setattr_copy(inode, ia);
193 out:
194 ia->ia_valid = old_ia_valid;
195 return ret;
196}
197
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201
202
203
204
205static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
206 unsigned long addr, unsigned long len,
207 unsigned long pgoff, unsigned long flags)
208{
209 unsigned long maxpages, lpages, nr, loop, ret;
210 struct inode *inode = file_inode(file);
211 struct page **pages = NULL, **ptr, *page;
212 loff_t isize;
213
214
215 lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
216 isize = i_size_read(inode);
217
218 ret = -ENOSYS;
219 maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT;
220 if (pgoff >= maxpages)
221 goto out;
222
223 if (maxpages - pgoff < lpages)
224 goto out;
225
226
227 pages = kcalloc(lpages, sizeof(struct page *), GFP_KERNEL);
228 if (!pages)
229 goto out_free;
230
231 nr = find_get_pages(inode->i_mapping, pgoff, lpages, pages);
232 if (nr != lpages)
233 goto out_free_pages;
234
235
236 ptr = pages;
237 page = *ptr++;
238 page++;
239 for (loop = lpages; loop > 1; loop--)
240 if (*ptr++ != page++)
241 goto out_free_pages;
242
243
244 ret = (unsigned long) page_address(pages[0]);
245
246out_free_pages:
247 ptr = pages;
248 for (loop = nr; loop > 0; loop--)
249 put_page(*ptr++);
250out_free:
251 kfree(pages);
252out:
253 return ret;
254}
255
256
257
258
259
260static int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma)
261{
262 if (!(vma->vm_flags & (VM_SHARED | VM_MAYSHARE)))
263 return -ENOSYS;
264
265 file_accessed(file);
266 vma->vm_ops = &generic_file_vm_ops;
267 return 0;
268}
269