Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 1 | /* mm/ashmem.c |
Cruz Julian Bishop | 2258937 | 2012-08-01 14:54:16 +1000 | [diff] [blame] | 2 | * |
| 3 | * Anonymous Shared Memory Subsystem, ashmem |
| 4 | * |
| 5 | * Copyright (C) 2008 Google, Inc. |
| 6 | * |
| 7 | * Robert Love <rlove@google.com> |
| 8 | * |
| 9 | * This software is licensed under the terms of the GNU General Public |
| 10 | * License version 2, as published by the Free Software Foundation, and |
| 11 | * may be copied, distributed, and modified under those terms. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU General Public License for more details. |
| 17 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 18 | |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 19 | #define pr_fmt(fmt) "ashmem: " fmt |
| 20 | |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 21 | #include <linux/module.h> |
| 22 | #include <linux/file.h> |
| 23 | #include <linux/fs.h> |
Hugh Dickins | 3f31d07 | 2012-05-29 15:06:40 -0700 | [diff] [blame] | 24 | #include <linux/falloc.h> |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 25 | #include <linux/miscdevice.h> |
| 26 | #include <linux/security.h> |
| 27 | #include <linux/mm.h> |
| 28 | #include <linux/mman.h> |
| 29 | #include <linux/uaccess.h> |
| 30 | #include <linux/personality.h> |
| 31 | #include <linux/bitops.h> |
| 32 | #include <linux/mutex.h> |
| 33 | #include <linux/shmem_fs.h> |
| 34 | #include "ashmem.h" |
| 35 | |
| 36 | #define ASHMEM_NAME_PREFIX "dev/ashmem/" |
| 37 | #define ASHMEM_NAME_PREFIX_LEN (sizeof(ASHMEM_NAME_PREFIX) - 1) |
| 38 | #define ASHMEM_FULL_NAME_LEN (ASHMEM_NAME_LEN + ASHMEM_NAME_PREFIX_LEN) |
| 39 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 40 | /** |
| 41 | * struct ashmem_area - The anonymous shared memory area |
| 42 | * @name: The optional name in /proc/pid/maps |
| 43 | * @unpinned_list: The list of all ashmem areas |
| 44 | * @file: The shmem-based backing file |
| 45 | * @size: The size of the mapping, in bytes |
| 46 | * @prot_masks: The allowed protection bits, as vm_flags |
| 47 | * |
| 48 | * The lifecycle of this structure is from our parent file's open() until |
| 49 | * its release(). It is also protected by 'ashmem_mutex' |
| 50 | * |
| 51 | * Warning: Mappings do NOT pin this structure; It dies on close() |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 52 | */ |
| 53 | struct ashmem_area { |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 54 | char name[ASHMEM_FULL_NAME_LEN]; |
| 55 | struct list_head unpinned_list; |
| 56 | struct file *file; |
| 57 | size_t size; |
| 58 | unsigned long prot_mask; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 59 | }; |
| 60 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 61 | /** |
| 62 | * struct ashmem_range - A range of unpinned/evictable pages |
| 63 | * @lru: The entry in the LRU list |
| 64 | * @unpinned: The entry in its area's unpinned list |
| 65 | * @asma: The associated anonymous shared memory area. |
| 66 | * @pgstart: The starting page (inclusive) |
| 67 | * @pgend: The ending page (inclusive) |
| 68 | * @purged: The purge status (ASHMEM_NOT or ASHMEM_WAS_PURGED) |
| 69 | * |
| 70 | * The lifecycle of this structure is from unpin to pin. |
| 71 | * It is protected by 'ashmem_mutex' |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 72 | */ |
| 73 | struct ashmem_range { |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 74 | struct list_head lru; |
| 75 | struct list_head unpinned; |
| 76 | struct ashmem_area *asma; |
| 77 | size_t pgstart; |
| 78 | size_t pgend; |
| 79 | unsigned int purged; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 80 | }; |
| 81 | |
| 82 | /* LRU list of unpinned pages, protected by ashmem_mutex */ |
| 83 | static LIST_HEAD(ashmem_lru_list); |
| 84 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 85 | /** |
| 86 | * long lru_count - The count of pages on our LRU list. |
| 87 | * |
| 88 | * This is protected by ashmem_mutex. |
| 89 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 90 | static unsigned long lru_count; |
| 91 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 92 | /** |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 93 | * ashmem_mutex - protects the list of and each individual ashmem_area |
| 94 | * |
| 95 | * Lock Ordering: ashmex_mutex -> i_mutex -> i_alloc_sem |
| 96 | */ |
| 97 | static DEFINE_MUTEX(ashmem_mutex); |
| 98 | |
| 99 | static struct kmem_cache *ashmem_area_cachep __read_mostly; |
| 100 | static struct kmem_cache *ashmem_range_cachep __read_mostly; |
| 101 | |
| 102 | #define range_size(range) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 103 | ((range)->pgend - (range)->pgstart + 1) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 104 | |
| 105 | #define range_on_lru(range) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 106 | ((range)->purged == ASHMEM_NOT_PURGED) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 107 | |
| 108 | #define page_range_subsumes_range(range, start, end) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 109 | (((range)->pgstart >= (start)) && ((range)->pgend <= (end))) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 110 | |
| 111 | #define page_range_subsumed_by_range(range, start, end) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 112 | (((range)->pgstart <= (start)) && ((range)->pgend >= (end))) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 113 | |
| 114 | #define page_in_range(range, page) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 115 | (((range)->pgstart <= (page)) && ((range)->pgend >= (page))) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 116 | |
| 117 | #define page_range_in_range(range, start, end) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 118 | (page_in_range(range, start) || page_in_range(range, end) || \ |
| 119 | page_range_subsumes_range(range, start, end)) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 120 | |
| 121 | #define range_before_page(range, page) \ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 122 | ((range)->pgend < (page)) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 123 | |
| 124 | #define PROT_MASK (PROT_EXEC | PROT_READ | PROT_WRITE) |
| 125 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 126 | /** |
| 127 | * lru_add() - Adds a range of memory to the LRU list |
| 128 | * @range: The memory range being added. |
| 129 | * |
| 130 | * The range is first added to the end (tail) of the LRU list. |
| 131 | * After this, the size of the range is added to @lru_count |
| 132 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 133 | static inline void lru_add(struct ashmem_range *range) |
| 134 | { |
| 135 | list_add_tail(&range->lru, &ashmem_lru_list); |
| 136 | lru_count += range_size(range); |
| 137 | } |
| 138 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 139 | /** |
| 140 | * lru_del() - Removes a range of memory from the LRU list |
| 141 | * @range: The memory range being removed |
| 142 | * |
| 143 | * The range is first deleted from the LRU list. |
| 144 | * After this, the size of the range is removed from @lru_count |
| 145 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 146 | static inline void lru_del(struct ashmem_range *range) |
| 147 | { |
| 148 | list_del(&range->lru); |
| 149 | lru_count -= range_size(range); |
| 150 | } |
| 151 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 152 | /** |
| 153 | * range_alloc() - Allocates and initializes a new ashmem_range structure |
| 154 | * @asma: The associated ashmem_area |
| 155 | * @prev_range: The previous ashmem_range in the sorted asma->unpinned list |
| 156 | * @purged: Initial purge status (ASMEM_NOT_PURGED or ASHMEM_WAS_PURGED) |
| 157 | * @start: The starting page (inclusive) |
| 158 | * @end: The ending page (inclusive) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 159 | * |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 160 | * This function is protected by ashmem_mutex. |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 161 | * |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 162 | * Return: 0 if successful, or -ENOMEM if there is an error |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 163 | */ |
| 164 | static int range_alloc(struct ashmem_area *asma, |
| 165 | struct ashmem_range *prev_range, unsigned int purged, |
| 166 | size_t start, size_t end) |
| 167 | { |
| 168 | struct ashmem_range *range; |
| 169 | |
| 170 | range = kmem_cache_zalloc(ashmem_range_cachep, GFP_KERNEL); |
| 171 | if (unlikely(!range)) |
| 172 | return -ENOMEM; |
| 173 | |
| 174 | range->asma = asma; |
| 175 | range->pgstart = start; |
| 176 | range->pgend = end; |
| 177 | range->purged = purged; |
| 178 | |
| 179 | list_add_tail(&range->unpinned, &prev_range->unpinned); |
| 180 | |
| 181 | if (range_on_lru(range)) |
| 182 | lru_add(range); |
| 183 | |
| 184 | return 0; |
| 185 | } |
| 186 | |
Cruz Julian Bishop | 4d2c9d5 | 2013-09-03 22:05:07 +1000 | [diff] [blame] | 187 | /** |
| 188 | * range_del() - Deletes and dealloctes an ashmem_range structure |
| 189 | * @range: The associated ashmem_range that has previously been allocated |
| 190 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 191 | static void range_del(struct ashmem_range *range) |
| 192 | { |
| 193 | list_del(&range->unpinned); |
| 194 | if (range_on_lru(range)) |
| 195 | lru_del(range); |
| 196 | kmem_cache_free(ashmem_range_cachep, range); |
| 197 | } |
| 198 | |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 199 | /** |
| 200 | * range_shrink() - Shrinks an ashmem_range |
| 201 | * @range: The associated ashmem_range being shrunk |
| 202 | * @start: The starting byte of the new range |
| 203 | * @end: The ending byte of the new range |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 204 | * |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 205 | * This does not modify the data inside the existing range in any way - It |
| 206 | * simply shrinks the boundaries of the range. |
| 207 | * |
| 208 | * Theoretically, with a little tweaking, this could eventually be changed |
| 209 | * to range_resize, and expand the lru_count if the new range is larger. |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 210 | */ |
| 211 | static inline void range_shrink(struct ashmem_range *range, |
| 212 | size_t start, size_t end) |
| 213 | { |
| 214 | size_t pre = range_size(range); |
| 215 | |
| 216 | range->pgstart = start; |
| 217 | range->pgend = end; |
| 218 | |
| 219 | if (range_on_lru(range)) |
| 220 | lru_count -= pre - range_size(range); |
| 221 | } |
| 222 | |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 223 | /** |
| 224 | * ashmem_open() - Opens an Anonymous Shared Memory structure |
| 225 | * @inode: The backing file's index node(?) |
| 226 | * @file: The backing file |
| 227 | * |
| 228 | * Please note that the ashmem_area is not returned by this function - It is |
| 229 | * instead written to "file->private_data". |
| 230 | * |
| 231 | * Return: 0 if successful, or another code if unsuccessful. |
| 232 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 233 | static int ashmem_open(struct inode *inode, struct file *file) |
| 234 | { |
| 235 | struct ashmem_area *asma; |
| 236 | int ret; |
| 237 | |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 238 | ret = generic_file_open(inode, file); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 239 | if (unlikely(ret)) |
| 240 | return ret; |
| 241 | |
| 242 | asma = kmem_cache_zalloc(ashmem_area_cachep, GFP_KERNEL); |
| 243 | if (unlikely(!asma)) |
| 244 | return -ENOMEM; |
| 245 | |
| 246 | INIT_LIST_HEAD(&asma->unpinned_list); |
| 247 | memcpy(asma->name, ASHMEM_NAME_PREFIX, ASHMEM_NAME_PREFIX_LEN); |
| 248 | asma->prot_mask = PROT_MASK; |
| 249 | file->private_data = asma; |
| 250 | |
| 251 | return 0; |
| 252 | } |
| 253 | |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 254 | /** |
| 255 | * ashmem_release() - Releases an Anonymous Shared Memory structure |
| 256 | * @ignored: The backing file's Index Node(?) - It is ignored here. |
| 257 | * @file: The backing file |
| 258 | * |
| 259 | * Return: 0 if successful. If it is anything else, go have a coffee and |
| 260 | * try again. |
| 261 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 262 | static int ashmem_release(struct inode *ignored, struct file *file) |
| 263 | { |
| 264 | struct ashmem_area *asma = file->private_data; |
| 265 | struct ashmem_range *range, *next; |
| 266 | |
| 267 | mutex_lock(&ashmem_mutex); |
| 268 | list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) |
| 269 | range_del(range); |
| 270 | mutex_unlock(&ashmem_mutex); |
| 271 | |
| 272 | if (asma->file) |
| 273 | fput(asma->file); |
| 274 | kmem_cache_free(ashmem_area_cachep, asma); |
| 275 | |
| 276 | return 0; |
| 277 | } |
| 278 | |
Cruz Julian Bishop | 781114c | 2013-09-03 22:05:08 +1000 | [diff] [blame] | 279 | /** |
| 280 | * ashmem_read() - Reads a set of bytes from an Ashmem-enabled file |
| 281 | * @file: The associated backing file. |
| 282 | * @buf: The buffer of data being written to |
| 283 | * @len: The number of bytes being read |
| 284 | * @pos: The position of the first byte to read. |
| 285 | * |
| 286 | * Return: 0 if successful, or another return code if not. |
| 287 | */ |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 288 | static ssize_t ashmem_read(struct file *file, char __user *buf, |
| 289 | size_t len, loff_t *pos) |
| 290 | { |
| 291 | struct ashmem_area *asma = file->private_data; |
| 292 | int ret = 0; |
| 293 | |
| 294 | mutex_lock(&ashmem_mutex); |
| 295 | |
| 296 | /* If size is not set, or set to 0, always return EOF. */ |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 297 | if (asma->size == 0) |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 298 | goto out_unlock; |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 299 | |
| 300 | if (!asma->file) { |
| 301 | ret = -EBADF; |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 302 | goto out_unlock; |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 303 | } |
| 304 | |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 305 | mutex_unlock(&ashmem_mutex); |
| 306 | |
| 307 | /* |
| 308 | * asma and asma->file are used outside the lock here. We assume |
| 309 | * once asma->file is set it will never be changed, and will not |
| 310 | * be destroyed until all references to the file are dropped and |
| 311 | * ashmem_release is called. |
| 312 | */ |
Al Viro | e145286 | 2015-04-03 15:09:38 -0400 | [diff] [blame] | 313 | ret = __vfs_read(asma->file, buf, len, pos); |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 314 | if (ret >= 0) { |
| 315 | /** Update backing file pos, since f_ops->read() doesn't */ |
| 316 | asma->file->f_pos = *pos; |
| 317 | } |
| 318 | return ret; |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 319 | |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 320 | out_unlock: |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 321 | mutex_unlock(&ashmem_mutex); |
| 322 | return ret; |
| 323 | } |
| 324 | |
| 325 | static loff_t ashmem_llseek(struct file *file, loff_t offset, int origin) |
| 326 | { |
| 327 | struct ashmem_area *asma = file->private_data; |
| 328 | int ret; |
| 329 | |
| 330 | mutex_lock(&ashmem_mutex); |
| 331 | |
| 332 | if (asma->size == 0) { |
| 333 | ret = -EINVAL; |
| 334 | goto out; |
| 335 | } |
| 336 | |
| 337 | if (!asma->file) { |
| 338 | ret = -EBADF; |
| 339 | goto out; |
| 340 | } |
| 341 | |
Al Viro | 91360b0 | 2014-08-19 11:08:22 -0400 | [diff] [blame] | 342 | ret = vfs_llseek(asma->file, offset, origin); |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 343 | if (ret < 0) |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 344 | goto out; |
Bjorn Bringert | 5154b93 | 2011-12-20 16:49:52 -0800 | [diff] [blame] | 345 | |
| 346 | /** Copy f_pos from backing file, since f_ops->llseek() sets it */ |
| 347 | file->f_pos = asma->file->f_pos; |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 348 | |
| 349 | out: |
| 350 | mutex_unlock(&ashmem_mutex); |
| 351 | return ret; |
| 352 | } |
| 353 | |
Konstantin Khlebnikov | 7cfce77 | 2012-03-21 02:56:33 -0300 | [diff] [blame] | 354 | static inline vm_flags_t calc_vm_may_flags(unsigned long prot) |
Arve Hjønnevåg | 56f76fc | 2011-12-20 16:49:50 -0800 | [diff] [blame] | 355 | { |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 356 | return _calc_vm_trans(prot, PROT_READ, VM_MAYREAD) | |
Arve Hjønnevåg | 56f76fc | 2011-12-20 16:49:50 -0800 | [diff] [blame] | 357 | _calc_vm_trans(prot, PROT_WRITE, VM_MAYWRITE) | |
| 358 | _calc_vm_trans(prot, PROT_EXEC, VM_MAYEXEC); |
| 359 | } |
Bjorn Bringert | 853ca7a | 2011-12-20 16:49:49 -0800 | [diff] [blame] | 360 | |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 361 | static int ashmem_mmap(struct file *file, struct vm_area_struct *vma) |
| 362 | { |
| 363 | struct ashmem_area *asma = file->private_data; |
| 364 | int ret = 0; |
| 365 | |
| 366 | mutex_lock(&ashmem_mutex); |
| 367 | |
| 368 | /* user needs to SET_SIZE before mapping */ |
| 369 | if (unlikely(!asma->size)) { |
| 370 | ret = -EINVAL; |
| 371 | goto out; |
| 372 | } |
| 373 | |
| 374 | /* requested protection bits must match our allowed protection mask */ |
Arve Hjønnevåg | 56f76fc | 2011-12-20 16:49:50 -0800 | [diff] [blame] | 375 | if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask)) & |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 376 | calc_vm_prot_bits(PROT_MASK))) { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 377 | ret = -EPERM; |
| 378 | goto out; |
| 379 | } |
Arve Hjønnevåg | 56f76fc | 2011-12-20 16:49:50 -0800 | [diff] [blame] | 380 | vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 381 | |
| 382 | if (!asma->file) { |
| 383 | char *name = ASHMEM_NAME_DEF; |
| 384 | struct file *vmfile; |
| 385 | |
| 386 | if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') |
| 387 | name = asma->name; |
| 388 | |
| 389 | /* ... and allocate the backing shmem file */ |
| 390 | vmfile = shmem_file_setup(name, asma->size, vma->vm_flags); |
| 391 | if (unlikely(IS_ERR(vmfile))) { |
| 392 | ret = PTR_ERR(vmfile); |
| 393 | goto out; |
| 394 | } |
| 395 | asma->file = vmfile; |
| 396 | } |
| 397 | get_file(asma->file); |
| 398 | |
| 399 | /* |
Tracey Dent | aa5af97 | 2012-01-22 21:28:44 -0500 | [diff] [blame] | 400 | * XXX - Reworked to use shmem_zero_setup() instead of |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 401 | * shmem_set_file while we're in staging. -jstultz |
| 402 | */ |
| 403 | if (vma->vm_flags & VM_SHARED) { |
| 404 | ret = shmem_zero_setup(vma); |
| 405 | if (ret) { |
| 406 | fput(asma->file); |
| 407 | goto out; |
| 408 | } |
| 409 | } |
| 410 | |
| 411 | if (vma->vm_file) |
| 412 | fput(vma->vm_file); |
| 413 | vma->vm_file = asma->file; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 414 | |
| 415 | out: |
| 416 | mutex_unlock(&ashmem_mutex); |
| 417 | return ret; |
| 418 | } |
| 419 | |
| 420 | /* |
Johannes Weiner | 6b4f779 | 2014-12-12 16:56:13 -0800 | [diff] [blame] | 421 | * ashmem_shrink - our cache shrinker, called from mm/vmscan.c |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 422 | * |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 423 | * 'nr_to_scan' is the number of objects to scan for freeing. |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 424 | * |
| 425 | * 'gfp_mask' is the mask of the allocation that got us into this mess. |
| 426 | * |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 427 | * Return value is the number of objects freed or -1 if we cannot |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 428 | * proceed without risk of deadlock (due to gfp_mask). |
| 429 | * |
| 430 | * We approximate LRU via least-recently-unpinned, jettisoning unpinned partial |
| 431 | * chunks of ashmem regions LRU-wise one-at-a-time until we hit 'nr_to_scan' |
| 432 | * pages freed. |
| 433 | */ |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 434 | static unsigned long |
| 435 | ashmem_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 436 | { |
| 437 | struct ashmem_range *range, *next; |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 438 | unsigned long freed = 0; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 439 | |
| 440 | /* We might recurse into filesystem code, so bail out if necessary */ |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 441 | if (!(sc->gfp_mask & __GFP_FS)) |
| 442 | return SHRINK_STOP; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 443 | |
| 444 | mutex_lock(&ashmem_mutex); |
| 445 | list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 446 | loff_t start = range->pgstart * PAGE_SIZE; |
Hugh Dickins | 3f31d07 | 2012-05-29 15:06:40 -0700 | [diff] [blame] | 447 | loff_t end = (range->pgend + 1) * PAGE_SIZE; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 448 | |
Anna Schumaker | 72c72bd | 2014-11-07 14:44:25 -0500 | [diff] [blame] | 449 | vfs_fallocate(range->asma->file, |
Fabian Holler | 002397c | 2015-01-07 10:39:52 +0100 | [diff] [blame] | 450 | FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, |
| 451 | start, end - start); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 452 | range->purged = ASHMEM_WAS_PURGED; |
| 453 | lru_del(range); |
| 454 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 455 | freed += range_size(range); |
| 456 | if (--sc->nr_to_scan <= 0) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 457 | break; |
| 458 | } |
| 459 | mutex_unlock(&ashmem_mutex); |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 460 | return freed; |
| 461 | } |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 462 | |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 463 | static unsigned long |
| 464 | ashmem_shrink_count(struct shrinker *shrink, struct shrink_control *sc) |
| 465 | { |
| 466 | /* |
| 467 | * note that lru_count is count of pages on the lru, not a count of |
| 468 | * objects on the list. This means the scan function needs to return the |
| 469 | * number of pages freed, not the number of objects scanned. |
| 470 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 471 | return lru_count; |
| 472 | } |
| 473 | |
| 474 | static struct shrinker ashmem_shrinker = { |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 475 | .count_objects = ashmem_shrink_count, |
| 476 | .scan_objects = ashmem_shrink_scan, |
| 477 | /* |
| 478 | * XXX (dchinner): I wish people would comment on why they need on |
| 479 | * significant changes to the default value here |
| 480 | */ |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 481 | .seeks = DEFAULT_SEEKS * 4, |
| 482 | }; |
| 483 | |
| 484 | static int set_prot_mask(struct ashmem_area *asma, unsigned long prot) |
| 485 | { |
| 486 | int ret = 0; |
| 487 | |
| 488 | mutex_lock(&ashmem_mutex); |
| 489 | |
| 490 | /* the user can only remove, not add, protection bits */ |
| 491 | if (unlikely((asma->prot_mask & prot) != prot)) { |
| 492 | ret = -EINVAL; |
| 493 | goto out; |
| 494 | } |
| 495 | |
| 496 | /* does the application expect PROT_READ to imply PROT_EXEC? */ |
| 497 | if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
| 498 | prot |= PROT_EXEC; |
| 499 | |
| 500 | asma->prot_mask = prot; |
| 501 | |
| 502 | out: |
| 503 | mutex_unlock(&ashmem_mutex); |
| 504 | return ret; |
| 505 | } |
| 506 | |
| 507 | static int set_name(struct ashmem_area *asma, void __user *name) |
| 508 | { |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 509 | int len; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 510 | int ret = 0; |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 511 | char local_name[ASHMEM_NAME_LEN]; |
| 512 | |
| 513 | /* |
| 514 | * Holding the ashmem_mutex while doing a copy_from_user might cause |
| 515 | * an data abort which would try to access mmap_sem. If another |
| 516 | * thread has invoked ashmem_mmap then it will be holding the |
| 517 | * semaphore and will be waiting for ashmem_mutex, there by leading to |
| 518 | * deadlock. We'll release the mutex and take the name to a local |
| 519 | * variable that does not need protection and later copy the local |
| 520 | * variable to the structure member with lock held. |
| 521 | */ |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 522 | len = strncpy_from_user(local_name, name, ASHMEM_NAME_LEN); |
| 523 | if (len < 0) |
| 524 | return len; |
| 525 | if (len == ASHMEM_NAME_LEN) |
| 526 | local_name[ASHMEM_NAME_LEN - 1] = '\0'; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 527 | mutex_lock(&ashmem_mutex); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 528 | /* cannot change an existing mapping's name */ |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 529 | if (unlikely(asma->file)) |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 530 | ret = -EINVAL; |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 531 | else |
| 532 | strcpy(asma->name + ASHMEM_NAME_PREFIX_LEN, local_name); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 533 | |
Todd Poynor | 077f6db9 | 2014-02-04 16:08:37 -0800 | [diff] [blame] | 534 | mutex_unlock(&ashmem_mutex); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 535 | return ret; |
| 536 | } |
| 537 | |
| 538 | static int get_name(struct ashmem_area *asma, void __user *name) |
| 539 | { |
| 540 | int ret = 0; |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 541 | size_t len; |
| 542 | /* |
| 543 | * Have a local variable to which we'll copy the content |
| 544 | * from asma with the lock held. Later we can copy this to the user |
| 545 | * space safely without holding any locks. So even if we proceed to |
| 546 | * wait for mmap_sem, it won't lead to deadlock. |
| 547 | */ |
| 548 | char local_name[ASHMEM_NAME_LEN]; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 549 | |
| 550 | mutex_lock(&ashmem_mutex); |
| 551 | if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 552 | /* |
| 553 | * Copying only `len', instead of ASHMEM_NAME_LEN, bytes |
| 554 | * prevents us from revealing one user's stack to another. |
| 555 | */ |
| 556 | len = strlen(asma->name + ASHMEM_NAME_PREFIX_LEN) + 1; |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 557 | memcpy(local_name, asma->name + ASHMEM_NAME_PREFIX_LEN, len); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 558 | } else { |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 559 | len = sizeof(ASHMEM_NAME_DEF); |
| 560 | memcpy(local_name, ASHMEM_NAME_DEF, len); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 561 | } |
| 562 | mutex_unlock(&ashmem_mutex); |
| 563 | |
Shankar Brahadeeswaran | e5834d6 | 2013-02-20 23:41:26 +0530 | [diff] [blame] | 564 | /* |
| 565 | * Now we are just copying from the stack variable to userland |
| 566 | * No lock held |
| 567 | */ |
| 568 | if (unlikely(copy_to_user(name, local_name, len))) |
| 569 | ret = -EFAULT; |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 570 | return ret; |
| 571 | } |
| 572 | |
| 573 | /* |
| 574 | * ashmem_pin - pin the given ashmem region, returning whether it was |
| 575 | * previously purged (ASHMEM_WAS_PURGED) or not (ASHMEM_NOT_PURGED). |
| 576 | * |
| 577 | * Caller must hold ashmem_mutex. |
| 578 | */ |
| 579 | static int ashmem_pin(struct ashmem_area *asma, size_t pgstart, size_t pgend) |
| 580 | { |
| 581 | struct ashmem_range *range, *next; |
| 582 | int ret = ASHMEM_NOT_PURGED; |
| 583 | |
| 584 | list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) { |
| 585 | /* moved past last applicable page; we can short circuit */ |
| 586 | if (range_before_page(range, pgstart)) |
| 587 | break; |
| 588 | |
| 589 | /* |
| 590 | * The user can ask us to pin pages that span multiple ranges, |
| 591 | * or to pin pages that aren't even unpinned, so this is messy. |
| 592 | * |
| 593 | * Four cases: |
| 594 | * 1. The requested range subsumes an existing range, so we |
| 595 | * just remove the entire matching range. |
| 596 | * 2. The requested range overlaps the start of an existing |
| 597 | * range, so we just update that range. |
| 598 | * 3. The requested range overlaps the end of an existing |
| 599 | * range, so we just update that range. |
| 600 | * 4. The requested range punches a hole in an existing range, |
| 601 | * so we have to update one side of the range and then |
| 602 | * create a new range for the other side. |
| 603 | */ |
| 604 | if (page_range_in_range(range, pgstart, pgend)) { |
| 605 | ret |= range->purged; |
| 606 | |
| 607 | /* Case #1: Easy. Just nuke the whole thing. */ |
| 608 | if (page_range_subsumes_range(range, pgstart, pgend)) { |
| 609 | range_del(range); |
| 610 | continue; |
| 611 | } |
| 612 | |
| 613 | /* Case #2: We overlap from the start, so adjust it */ |
| 614 | if (range->pgstart >= pgstart) { |
| 615 | range_shrink(range, pgend + 1, range->pgend); |
| 616 | continue; |
| 617 | } |
| 618 | |
| 619 | /* Case #3: We overlap from the rear, so adjust it */ |
| 620 | if (range->pgend <= pgend) { |
| 621 | range_shrink(range, range->pgstart, pgstart-1); |
| 622 | continue; |
| 623 | } |
| 624 | |
| 625 | /* |
| 626 | * Case #4: We eat a chunk out of the middle. A bit |
| 627 | * more complicated, we allocate a new range for the |
| 628 | * second half and adjust the first chunk's endpoint. |
| 629 | */ |
| 630 | range_alloc(asma, range, range->purged, |
| 631 | pgend + 1, range->pgend); |
| 632 | range_shrink(range, range->pgstart, pgstart - 1); |
| 633 | break; |
| 634 | } |
| 635 | } |
| 636 | |
| 637 | return ret; |
| 638 | } |
| 639 | |
| 640 | /* |
| 641 | * ashmem_unpin - unpin the given range of pages. Returns zero on success. |
| 642 | * |
| 643 | * Caller must hold ashmem_mutex. |
| 644 | */ |
| 645 | static int ashmem_unpin(struct ashmem_area *asma, size_t pgstart, size_t pgend) |
| 646 | { |
| 647 | struct ashmem_range *range, *next; |
| 648 | unsigned int purged = ASHMEM_NOT_PURGED; |
| 649 | |
| 650 | restart: |
| 651 | list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) { |
| 652 | /* short circuit: this is our insertion point */ |
| 653 | if (range_before_page(range, pgstart)) |
| 654 | break; |
| 655 | |
| 656 | /* |
| 657 | * The user can ask us to unpin pages that are already entirely |
| 658 | * or partially pinned. We handle those two cases here. |
| 659 | */ |
| 660 | if (page_range_subsumed_by_range(range, pgstart, pgend)) |
| 661 | return 0; |
| 662 | if (page_range_in_range(range, pgstart, pgend)) { |
| 663 | pgstart = min_t(size_t, range->pgstart, pgstart), |
| 664 | pgend = max_t(size_t, range->pgend, pgend); |
| 665 | purged |= range->purged; |
| 666 | range_del(range); |
| 667 | goto restart; |
| 668 | } |
| 669 | } |
| 670 | |
| 671 | return range_alloc(asma, range, purged, pgstart, pgend); |
| 672 | } |
| 673 | |
| 674 | /* |
| 675 | * ashmem_get_pin_status - Returns ASHMEM_IS_UNPINNED if _any_ pages in the |
| 676 | * given interval are unpinned and ASHMEM_IS_PINNED otherwise. |
| 677 | * |
| 678 | * Caller must hold ashmem_mutex. |
| 679 | */ |
| 680 | static int ashmem_get_pin_status(struct ashmem_area *asma, size_t pgstart, |
| 681 | size_t pgend) |
| 682 | { |
| 683 | struct ashmem_range *range; |
| 684 | int ret = ASHMEM_IS_PINNED; |
| 685 | |
| 686 | list_for_each_entry(range, &asma->unpinned_list, unpinned) { |
| 687 | if (range_before_page(range, pgstart)) |
| 688 | break; |
| 689 | if (page_range_in_range(range, pgstart, pgend)) { |
| 690 | ret = ASHMEM_IS_UNPINNED; |
| 691 | break; |
| 692 | } |
| 693 | } |
| 694 | |
| 695 | return ret; |
| 696 | } |
| 697 | |
| 698 | static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd, |
| 699 | void __user *p) |
| 700 | { |
| 701 | struct ashmem_pin pin; |
| 702 | size_t pgstart, pgend; |
| 703 | int ret = -EINVAL; |
| 704 | |
| 705 | if (unlikely(!asma->file)) |
| 706 | return -EINVAL; |
| 707 | |
| 708 | if (unlikely(copy_from_user(&pin, p, sizeof(pin)))) |
| 709 | return -EFAULT; |
| 710 | |
| 711 | /* per custom, you can pass zero for len to mean "everything onward" */ |
| 712 | if (!pin.len) |
| 713 | pin.len = PAGE_ALIGN(asma->size) - pin.offset; |
| 714 | |
| 715 | if (unlikely((pin.offset | pin.len) & ~PAGE_MASK)) |
| 716 | return -EINVAL; |
| 717 | |
| 718 | if (unlikely(((__u32) -1) - pin.offset < pin.len)) |
| 719 | return -EINVAL; |
| 720 | |
| 721 | if (unlikely(PAGE_ALIGN(asma->size) < pin.offset + pin.len)) |
| 722 | return -EINVAL; |
| 723 | |
| 724 | pgstart = pin.offset / PAGE_SIZE; |
| 725 | pgend = pgstart + (pin.len / PAGE_SIZE) - 1; |
| 726 | |
| 727 | mutex_lock(&ashmem_mutex); |
| 728 | |
| 729 | switch (cmd) { |
| 730 | case ASHMEM_PIN: |
| 731 | ret = ashmem_pin(asma, pgstart, pgend); |
| 732 | break; |
| 733 | case ASHMEM_UNPIN: |
| 734 | ret = ashmem_unpin(asma, pgstart, pgend); |
| 735 | break; |
| 736 | case ASHMEM_GET_PIN_STATUS: |
| 737 | ret = ashmem_get_pin_status(asma, pgstart, pgend); |
| 738 | break; |
| 739 | } |
| 740 | |
| 741 | mutex_unlock(&ashmem_mutex); |
| 742 | |
| 743 | return ret; |
| 744 | } |
| 745 | |
| 746 | static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| 747 | { |
| 748 | struct ashmem_area *asma = file->private_data; |
| 749 | long ret = -ENOTTY; |
| 750 | |
| 751 | switch (cmd) { |
| 752 | case ASHMEM_SET_NAME: |
Fabian Holler | 1703ca9 | 2015-01-07 10:39:54 +0100 | [diff] [blame] | 753 | ret = set_name(asma, (void __user *)arg); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 754 | break; |
| 755 | case ASHMEM_GET_NAME: |
Fabian Holler | 1703ca9 | 2015-01-07 10:39:54 +0100 | [diff] [blame] | 756 | ret = get_name(asma, (void __user *)arg); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 757 | break; |
| 758 | case ASHMEM_SET_SIZE: |
| 759 | ret = -EINVAL; |
| 760 | if (!asma->file) { |
| 761 | ret = 0; |
| 762 | asma->size = (size_t) arg; |
| 763 | } |
| 764 | break; |
| 765 | case ASHMEM_GET_SIZE: |
| 766 | ret = asma->size; |
| 767 | break; |
| 768 | case ASHMEM_SET_PROT_MASK: |
| 769 | ret = set_prot_mask(asma, arg); |
| 770 | break; |
| 771 | case ASHMEM_GET_PROT_MASK: |
| 772 | ret = asma->prot_mask; |
| 773 | break; |
| 774 | case ASHMEM_PIN: |
| 775 | case ASHMEM_UNPIN: |
| 776 | case ASHMEM_GET_PIN_STATUS: |
Fabian Holler | 1703ca9 | 2015-01-07 10:39:54 +0100 | [diff] [blame] | 777 | ret = ashmem_pin_unpin(asma, cmd, (void __user *)arg); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 778 | break; |
| 779 | case ASHMEM_PURGE_ALL_CACHES: |
| 780 | ret = -EPERM; |
| 781 | if (capable(CAP_SYS_ADMIN)) { |
Colin Cross | 33e8fc4 | 2011-12-20 16:49:53 -0800 | [diff] [blame] | 782 | struct shrink_control sc = { |
| 783 | .gfp_mask = GFP_KERNEL, |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 784 | .nr_to_scan = LONG_MAX, |
Colin Cross | 33e8fc4 | 2011-12-20 16:49:53 -0800 | [diff] [blame] | 785 | }; |
John Stultz | 5957324 | 2013-10-21 09:58:07 -0700 | [diff] [blame] | 786 | ret = ashmem_shrink_count(&ashmem_shrinker, &sc); |
Dave Chinner | 7dc19d5 | 2013-08-28 10:18:11 +1000 | [diff] [blame] | 787 | ashmem_shrink_scan(&ashmem_shrinker, &sc); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 788 | } |
| 789 | break; |
| 790 | } |
| 791 | |
| 792 | return ret; |
| 793 | } |
| 794 | |
Serban Constantinescu | e9f5b81 | 2013-03-05 15:27:38 +0000 | [diff] [blame] | 795 | /* support of 32bit userspace on 64bit platforms */ |
| 796 | #ifdef CONFIG_COMPAT |
Marlies Ruck | 017ca3b | 2013-05-10 16:26:30 -0400 | [diff] [blame] | 797 | static long compat_ashmem_ioctl(struct file *file, unsigned int cmd, |
| 798 | unsigned long arg) |
Serban Constantinescu | e9f5b81 | 2013-03-05 15:27:38 +0000 | [diff] [blame] | 799 | { |
Serban Constantinescu | e9f5b81 | 2013-03-05 15:27:38 +0000 | [diff] [blame] | 800 | switch (cmd) { |
| 801 | case COMPAT_ASHMEM_SET_SIZE: |
| 802 | cmd = ASHMEM_SET_SIZE; |
| 803 | break; |
| 804 | case COMPAT_ASHMEM_SET_PROT_MASK: |
| 805 | cmd = ASHMEM_SET_PROT_MASK; |
| 806 | break; |
| 807 | } |
| 808 | return ashmem_ioctl(file, cmd, arg); |
| 809 | } |
| 810 | #endif |
| 811 | |
Tracey Dent | aa5af97 | 2012-01-22 21:28:44 -0500 | [diff] [blame] | 812 | static const struct file_operations ashmem_fops = { |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 813 | .owner = THIS_MODULE, |
| 814 | .open = ashmem_open, |
| 815 | .release = ashmem_release, |
John Stultz | 1efb343 | 2011-12-20 16:49:54 -0800 | [diff] [blame] | 816 | .read = ashmem_read, |
| 817 | .llseek = ashmem_llseek, |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 818 | .mmap = ashmem_mmap, |
| 819 | .unlocked_ioctl = ashmem_ioctl, |
Serban Constantinescu | e9f5b81 | 2013-03-05 15:27:38 +0000 | [diff] [blame] | 820 | #ifdef CONFIG_COMPAT |
| 821 | .compat_ioctl = compat_ashmem_ioctl, |
| 822 | #endif |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 823 | }; |
| 824 | |
| 825 | static struct miscdevice ashmem_misc = { |
| 826 | .minor = MISC_DYNAMIC_MINOR, |
| 827 | .name = "ashmem", |
| 828 | .fops = &ashmem_fops, |
| 829 | }; |
| 830 | |
| 831 | static int __init ashmem_init(void) |
| 832 | { |
| 833 | int ret; |
| 834 | |
| 835 | ashmem_area_cachep = kmem_cache_create("ashmem_area_cache", |
| 836 | sizeof(struct ashmem_area), |
| 837 | 0, 0, NULL); |
| 838 | if (unlikely(!ashmem_area_cachep)) { |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 839 | pr_err("failed to create slab cache\n"); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 840 | return -ENOMEM; |
| 841 | } |
| 842 | |
| 843 | ashmem_range_cachep = kmem_cache_create("ashmem_range_cache", |
| 844 | sizeof(struct ashmem_range), |
| 845 | 0, 0, NULL); |
| 846 | if (unlikely(!ashmem_range_cachep)) { |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 847 | pr_err("failed to create slab cache\n"); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 848 | return -ENOMEM; |
| 849 | } |
| 850 | |
| 851 | ret = misc_register(&ashmem_misc); |
| 852 | if (unlikely(ret)) { |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 853 | pr_err("failed to register misc device!\n"); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 854 | return ret; |
| 855 | } |
| 856 | |
| 857 | register_shrinker(&ashmem_shrinker); |
| 858 | |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 859 | pr_info("initialized\n"); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 860 | |
| 861 | return 0; |
| 862 | } |
| 863 | |
| 864 | static void __exit ashmem_exit(void) |
| 865 | { |
| 866 | int ret; |
| 867 | |
| 868 | unregister_shrinker(&ashmem_shrinker); |
| 869 | |
| 870 | ret = misc_deregister(&ashmem_misc); |
| 871 | if (unlikely(ret)) |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 872 | pr_err("failed to unregister misc device!\n"); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 873 | |
| 874 | kmem_cache_destroy(ashmem_range_cachep); |
| 875 | kmem_cache_destroy(ashmem_area_cachep); |
| 876 | |
Sachin Kamat | c810a39 | 2012-06-05 16:40:10 +0530 | [diff] [blame] | 877 | pr_info("unloaded\n"); |
Robert Love | 11980c2 | 2011-12-20 16:49:48 -0800 | [diff] [blame] | 878 | } |
| 879 | |
| 880 | module_init(ashmem_init); |
| 881 | module_exit(ashmem_exit); |
| 882 | |
| 883 | MODULE_LICENSE("GPL"); |