~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/mm/util.c

Version: ~ [ linux-5.11 ] ~ [ linux-5.10.17 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.99 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.176 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.221 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.257 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.257 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 #include <linux/mm.h>
  2 #include <linux/slab.h>
  3 #include <linux/string.h>
  4 #include <linux/export.h>
  5 #include <linux/err.h>
  6 #include <linux/sched.h>
  7 #include <linux/security.h>
  8 #include <linux/swap.h>
  9 #include <linux/swapops.h>
 10 #include <linux/mman.h>
 11 #include <linux/hugetlb.h>
 12 
 13 #include <asm/uaccess.h>
 14 
 15 #include "internal.h"
 16 
 17 #define CREATE_TRACE_POINTS
 18 #include <trace/events/kmem.h>
 19 
 20 /**
 21  * kstrdup - allocate space for and copy an existing string
 22  * @s: the string to duplicate
 23  * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 24  */
 25 char *kstrdup(const char *s, gfp_t gfp)
 26 {
 27         size_t len;
 28         char *buf;
 29 
 30         if (!s)
 31                 return NULL;
 32 
 33         len = strlen(s) + 1;
 34         buf = kmalloc_track_caller(len, gfp);
 35         if (buf)
 36                 memcpy(buf, s, len);
 37         return buf;
 38 }
 39 EXPORT_SYMBOL(kstrdup);
 40 
 41 /**
 42  * kstrndup - allocate space for and copy an existing string
 43  * @s: the string to duplicate
 44  * @max: read at most @max chars from @s
 45  * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 46  */
 47 char *kstrndup(const char *s, size_t max, gfp_t gfp)
 48 {
 49         size_t len;
 50         char *buf;
 51 
 52         if (!s)
 53                 return NULL;
 54 
 55         len = strnlen(s, max);
 56         buf = kmalloc_track_caller(len+1, gfp);
 57         if (buf) {
 58                 memcpy(buf, s, len);
 59                 buf[len] = '\0';
 60         }
 61         return buf;
 62 }
 63 EXPORT_SYMBOL(kstrndup);
 64 
 65 /**
 66  * kmemdup - duplicate region of memory
 67  *
 68  * @src: memory region to duplicate
 69  * @len: memory region length
 70  * @gfp: GFP mask to use
 71  */
 72 void *kmemdup(const void *src, size_t len, gfp_t gfp)
 73 {
 74         void *p;
 75 
 76         p = kmalloc_track_caller(len, gfp);
 77         if (p)
 78                 memcpy(p, src, len);
 79         return p;
 80 }
 81 EXPORT_SYMBOL(kmemdup);
 82 
 83 /**
 84  * memdup_user - duplicate memory region from user space
 85  *
 86  * @src: source address in user space
 87  * @len: number of bytes to copy
 88  *
 89  * Returns an ERR_PTR() on failure.
 90  */
 91 void *memdup_user(const void __user *src, size_t len)
 92 {
 93         void *p;
 94 
 95         /*
 96          * Always use GFP_KERNEL, since copy_from_user() can sleep and
 97          * cause pagefault, which makes it pointless to use GFP_NOFS
 98          * or GFP_ATOMIC.
 99          */
100         p = kmalloc_track_caller(len, GFP_KERNEL);
101         if (!p)
102                 return ERR_PTR(-ENOMEM);
103 
104         if (copy_from_user(p, src, len)) {
105                 kfree(p);
106                 return ERR_PTR(-EFAULT);
107         }
108 
109         return p;
110 }
111 EXPORT_SYMBOL(memdup_user);
112 
113 static __always_inline void *__do_krealloc(const void *p, size_t new_size,
114                                            gfp_t flags)
115 {
116         void *ret;
117         size_t ks = 0;
118 
119         if (p)
120                 ks = ksize(p);
121 
122         if (ks >= new_size)
123                 return (void *)p;
124 
125         ret = kmalloc_track_caller(new_size, flags);
126         if (ret && p)
127                 memcpy(ret, p, ks);
128 
129         return ret;
130 }
131 
132 /**
133  * __krealloc - like krealloc() but don't free @p.
134  * @p: object to reallocate memory for.
135  * @new_size: how many bytes of memory are required.
136  * @flags: the type of memory to allocate.
137  *
138  * This function is like krealloc() except it never frees the originally
139  * allocated buffer. Use this if you don't want to free the buffer immediately
140  * like, for example, with RCU.
141  */
142 void *__krealloc(const void *p, size_t new_size, gfp_t flags)
143 {
144         if (unlikely(!new_size))
145                 return ZERO_SIZE_PTR;
146 
147         return __do_krealloc(p, new_size, flags);
148 
149 }
150 EXPORT_SYMBOL(__krealloc);
151 
152 /**
153  * krealloc - reallocate memory. The contents will remain unchanged.
154  * @p: object to reallocate memory for.
155  * @new_size: how many bytes of memory are required.
156  * @flags: the type of memory to allocate.
157  *
158  * The contents of the object pointed to are preserved up to the
159  * lesser of the new and old sizes.  If @p is %NULL, krealloc()
160  * behaves exactly like kmalloc().  If @new_size is 0 and @p is not a
161  * %NULL pointer, the object pointed to is freed.
162  */
163 void *krealloc(const void *p, size_t new_size, gfp_t flags)
164 {
165         void *ret;
166 
167         if (unlikely(!new_size)) {
168                 kfree(p);
169                 return ZERO_SIZE_PTR;
170         }
171 
172         ret = __do_krealloc(p, new_size, flags);
173         if (ret && p != ret)
174                 kfree(p);
175 
176         return ret;
177 }
178 EXPORT_SYMBOL(krealloc);
179 
180 /**
181  * kzfree - like kfree but zero memory
182  * @p: object to free memory of
183  *
184  * The memory of the object @p points to is zeroed before freed.
185  * If @p is %NULL, kzfree() does nothing.
186  *
187  * Note: this function zeroes the whole allocated buffer which can be a good
188  * deal bigger than the requested buffer size passed to kmalloc(). So be
189  * careful when using this function in performance sensitive code.
190  */
191 void kzfree(const void *p)
192 {
193         size_t ks;
194         void *mem = (void *)p;
195 
196         if (unlikely(ZERO_OR_NULL_PTR(mem)))
197                 return;
198         ks = ksize(mem);
199         memset(mem, 0, ks);
200         kfree(mem);
201 }
202 EXPORT_SYMBOL(kzfree);
203 
204 /*
205  * strndup_user - duplicate an existing string from user space
206  * @s: The string to duplicate
207  * @n: Maximum number of bytes to copy, including the trailing NUL.
208  */
209 char *strndup_user(const char __user *s, long n)
210 {
211         char *p;
212         long length;
213 
214         length = strnlen_user(s, n);
215 
216         if (!length)
217                 return ERR_PTR(-EFAULT);
218 
219         if (length > n)
220                 return ERR_PTR(-EINVAL);
221 
222         p = memdup_user(s, length);
223 
224         if (IS_ERR(p))
225                 return p;
226 
227         p[length - 1] = '\0';
228 
229         return p;
230 }
231 EXPORT_SYMBOL(strndup_user);
232 
233 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
234                 struct vm_area_struct *prev, struct rb_node *rb_parent)
235 {
236         struct vm_area_struct *next;
237 
238         vma->vm_prev = prev;
239         if (prev) {
240                 next = prev->vm_next;
241                 prev->vm_next = vma;
242         } else {
243                 mm->mmap = vma;
244                 if (rb_parent)
245                         next = rb_entry(rb_parent,
246                                         struct vm_area_struct, vm_rb);
247                 else
248                         next = NULL;
249         }
250         vma->vm_next = next;
251         if (next)
252                 next->vm_prev = vma;
253 }
254 
255 /* Check if the vma is being used as a stack by this task */
256 static int vm_is_stack_for_task(struct task_struct *t,
257                                 struct vm_area_struct *vma)
258 {
259         return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
260 }
261 
262 /*
263  * Check if the vma is being used as a stack.
264  * If is_group is non-zero, check in the entire thread group or else
265  * just check in the current task. Returns the pid of the task that
266  * the vma is stack for.
267  */
268 pid_t vm_is_stack(struct task_struct *task,
269                   struct vm_area_struct *vma, int in_group)
270 {
271         pid_t ret = 0;
272 
273         if (vm_is_stack_for_task(task, vma))
274                 return task->pid;
275 
276         if (in_group) {
277                 struct task_struct *t;
278                 rcu_read_lock();
279                 if (!pid_alive(task))
280                         goto done;
281 
282                 t = task;
283                 do {
284                         if (vm_is_stack_for_task(t, vma)) {
285                                 ret = t->pid;
286                                 goto done;
287                         }
288                 } while_each_thread(task, t);
289 done:
290                 rcu_read_unlock();
291         }
292 
293         return ret;
294 }
295 
296 #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
297 void arch_pick_mmap_layout(struct mm_struct *mm)
298 {
299         mm->mmap_base = TASK_UNMAPPED_BASE;
300         mm->get_unmapped_area = arch_get_unmapped_area;
301 }
302 #endif
303 
304 /*
305  * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
306  * back to the regular GUP.
307  * If the architecture not support this function, simply return with no
308  * page pinned
309  */
310 int __attribute__((weak)) __get_user_pages_fast(unsigned long start,
311                                  int nr_pages, int write, struct page **pages)
312 {
313         return 0;
314 }
315 EXPORT_SYMBOL_GPL(__get_user_pages_fast);
316 
317 /**
318  * get_user_pages_fast() - pin user pages in memory
319  * @start:      starting user address
320  * @nr_pages:   number of pages from start to pin
321  * @write:      whether pages will be written to
322  * @pages:      array that receives pointers to the pages pinned.
323  *              Should be at least nr_pages long.
324  *
325  * Returns number of pages pinned. This may be fewer than the number
326  * requested. If nr_pages is 0 or negative, returns 0. If no pages
327  * were pinned, returns -errno.
328  *
329  * get_user_pages_fast provides equivalent functionality to get_user_pages,
330  * operating on current and current->mm, with force=0 and vma=NULL. However
331  * unlike get_user_pages, it must be called without mmap_sem held.
332  *
333  * get_user_pages_fast may take mmap_sem and page table locks, so no
334  * assumptions can be made about lack of locking. get_user_pages_fast is to be
335  * implemented in a way that is advantageous (vs get_user_pages()) when the
336  * user memory area is already faulted in and present in ptes. However if the
337  * pages have to be faulted in, it may turn out to be slightly slower so
338  * callers need to carefully consider what to use. On many architectures,
339  * get_user_pages_fast simply falls back to get_user_pages.
340  */
341 int __attribute__((weak)) get_user_pages_fast(unsigned long start,
342                                 int nr_pages, int write, struct page **pages)
343 {
344         struct mm_struct *mm = current->mm;
345         int ret;
346 
347         down_read(&mm->mmap_sem);
348         ret = get_user_pages(current, mm, start, nr_pages,
349                                         write, 0, pages, NULL);
350         up_read(&mm->mmap_sem);
351 
352         return ret;
353 }
354 EXPORT_SYMBOL_GPL(get_user_pages_fast);
355 
356 unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
357         unsigned long len, unsigned long prot,
358         unsigned long flag, unsigned long pgoff)
359 {
360         unsigned long ret;
361         struct mm_struct *mm = current->mm;
362         unsigned long populate;
363 
364         ret = security_mmap_file(file, prot, flag);
365         if (!ret) {
366                 down_write(&mm->mmap_sem);
367                 ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff,
368                                     &populate);
369                 up_write(&mm->mmap_sem);
370                 if (populate)
371                         mm_populate(ret, populate);
372         }
373         return ret;
374 }
375 
376 unsigned long vm_mmap(struct file *file, unsigned long addr,
377         unsigned long len, unsigned long prot,
378         unsigned long flag, unsigned long offset)
379 {
380         if (unlikely(offset + PAGE_ALIGN(len) < offset))
381                 return -EINVAL;
382         if (unlikely(offset & ~PAGE_MASK))
383                 return -EINVAL;
384 
385         return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
386 }
387 EXPORT_SYMBOL(vm_mmap);
388 
389 struct address_space *page_mapping(struct page *page)
390 {
391         struct address_space *mapping = page->mapping;
392 
393         /* This happens if someone calls flush_dcache_page on slab page */
394         if (unlikely(PageSlab(page)))
395                 return NULL;
396 
397         if (unlikely(PageSwapCache(page))) {
398                 swp_entry_t entry;
399 
400                 entry.val = page_private(page);
401                 mapping = swap_address_space(entry);
402         } else if ((unsigned long)mapping & PAGE_MAPPING_ANON)
403                 mapping = NULL;
404         return mapping;
405 }
406 
407 /*
408  * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used
409  */
410 unsigned long vm_commit_limit(void)
411 {
412         return ((totalram_pages - hugetlb_total_pages())
413                 * sysctl_overcommit_ratio / 100) + total_swap_pages;
414 }
415 
416 
417 /* Tracepoints definitions. */
418 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
419 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
420 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
421 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
422 EXPORT_TRACEPOINT_SYMBOL(kfree);
423 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
424 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp