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v3.1
  1#include <linux/mm.h>
  2#include <linux/slab.h>
  3#include <linux/string.h>
  4#include <linux/module.h>
 
  5#include <linux/err.h>
  6#include <linux/sched.h>
 
 
 
 
 
 
 
  7#include <asm/uaccess.h>
  8
  9#include "internal.h"
 10
 11#define CREATE_TRACE_POINTS
 12#include <trace/events/kmem.h>
 13
 14/**
 15 * kstrdup - allocate space for and copy an existing string
 16 * @s: the string to duplicate
 17 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 18 */
 19char *kstrdup(const char *s, gfp_t gfp)
 20{
 21	size_t len;
 22	char *buf;
 23
 24	if (!s)
 25		return NULL;
 26
 27	len = strlen(s) + 1;
 28	buf = kmalloc_track_caller(len, gfp);
 29	if (buf)
 30		memcpy(buf, s, len);
 31	return buf;
 32}
 33EXPORT_SYMBOL(kstrdup);
 34
 35/**
 36 * kstrndup - allocate space for and copy an existing string
 37 * @s: the string to duplicate
 38 * @max: read at most @max chars from @s
 39 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 40 */
 41char *kstrndup(const char *s, size_t max, gfp_t gfp)
 42{
 43	size_t len;
 44	char *buf;
 45
 46	if (!s)
 47		return NULL;
 48
 49	len = strnlen(s, max);
 50	buf = kmalloc_track_caller(len+1, gfp);
 51	if (buf) {
 52		memcpy(buf, s, len);
 53		buf[len] = '\0';
 54	}
 55	return buf;
 56}
 57EXPORT_SYMBOL(kstrndup);
 58
 59/**
 60 * kmemdup - duplicate region of memory
 61 *
 62 * @src: memory region to duplicate
 63 * @len: memory region length
 64 * @gfp: GFP mask to use
 65 */
 66void *kmemdup(const void *src, size_t len, gfp_t gfp)
 67{
 68	void *p;
 69
 70	p = kmalloc_track_caller(len, gfp);
 71	if (p)
 72		memcpy(p, src, len);
 73	return p;
 74}
 75EXPORT_SYMBOL(kmemdup);
 76
 77/**
 78 * memdup_user - duplicate memory region from user space
 79 *
 80 * @src: source address in user space
 81 * @len: number of bytes to copy
 82 *
 83 * Returns an ERR_PTR() on failure.
 84 */
 85void *memdup_user(const void __user *src, size_t len)
 86{
 87	void *p;
 88
 89	/*
 90	 * Always use GFP_KERNEL, since copy_from_user() can sleep and
 91	 * cause pagefault, which makes it pointless to use GFP_NOFS
 92	 * or GFP_ATOMIC.
 93	 */
 94	p = kmalloc_track_caller(len, GFP_KERNEL);
 95	if (!p)
 96		return ERR_PTR(-ENOMEM);
 97
 98	if (copy_from_user(p, src, len)) {
 99		kfree(p);
100		return ERR_PTR(-EFAULT);
101	}
102
103	return p;
104}
105EXPORT_SYMBOL(memdup_user);
106
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
107/**
108 * __krealloc - like krealloc() but don't free @p.
109 * @p: object to reallocate memory for.
110 * @new_size: how many bytes of memory are required.
111 * @flags: the type of memory to allocate.
112 *
113 * This function is like krealloc() except it never frees the originally
114 * allocated buffer. Use this if you don't want to free the buffer immediately
115 * like, for example, with RCU.
116 */
117void *__krealloc(const void *p, size_t new_size, gfp_t flags)
118{
119	void *ret;
120	size_t ks = 0;
121
122	if (unlikely(!new_size))
123		return ZERO_SIZE_PTR;
124
125	if (p)
126		ks = ksize(p);
127
128	if (ks >= new_size)
129		return (void *)p;
130
131	ret = kmalloc_track_caller(new_size, flags);
132	if (ret && p)
133		memcpy(ret, p, ks);
134
135	return ret;
136}
137EXPORT_SYMBOL(__krealloc);
138
139/**
140 * krealloc - reallocate memory. The contents will remain unchanged.
141 * @p: object to reallocate memory for.
142 * @new_size: how many bytes of memory are required.
143 * @flags: the type of memory to allocate.
144 *
145 * The contents of the object pointed to are preserved up to the
146 * lesser of the new and old sizes.  If @p is %NULL, krealloc()
147 * behaves exactly like kmalloc().  If @size is 0 and @p is not a
148 * %NULL pointer, the object pointed to is freed.
149 */
150void *krealloc(const void *p, size_t new_size, gfp_t flags)
151{
152	void *ret;
153
154	if (unlikely(!new_size)) {
155		kfree(p);
156		return ZERO_SIZE_PTR;
157	}
158
159	ret = __krealloc(p, new_size, flags);
160	if (ret && p != ret)
161		kfree(p);
162
163	return ret;
164}
165EXPORT_SYMBOL(krealloc);
166
167/**
168 * kzfree - like kfree but zero memory
169 * @p: object to free memory of
170 *
171 * The memory of the object @p points to is zeroed before freed.
172 * If @p is %NULL, kzfree() does nothing.
173 *
174 * Note: this function zeroes the whole allocated buffer which can be a good
175 * deal bigger than the requested buffer size passed to kmalloc(). So be
176 * careful when using this function in performance sensitive code.
177 */
178void kzfree(const void *p)
179{
180	size_t ks;
181	void *mem = (void *)p;
182
183	if (unlikely(ZERO_OR_NULL_PTR(mem)))
184		return;
185	ks = ksize(mem);
186	memset(mem, 0, ks);
187	kfree(mem);
188}
189EXPORT_SYMBOL(kzfree);
190
191/*
192 * strndup_user - duplicate an existing string from user space
193 * @s: The string to duplicate
194 * @n: Maximum number of bytes to copy, including the trailing NUL.
195 */
196char *strndup_user(const char __user *s, long n)
197{
198	char *p;
199	long length;
200
201	length = strnlen_user(s, n);
202
203	if (!length)
204		return ERR_PTR(-EFAULT);
205
206	if (length > n)
207		return ERR_PTR(-EINVAL);
208
209	p = memdup_user(s, length);
210
211	if (IS_ERR(p))
212		return p;
213
214	p[length - 1] = '\0';
215
216	return p;
217}
218EXPORT_SYMBOL(strndup_user);
219
220void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
221		struct vm_area_struct *prev, struct rb_node *rb_parent)
222{
223	struct vm_area_struct *next;
224
225	vma->vm_prev = prev;
226	if (prev) {
227		next = prev->vm_next;
228		prev->vm_next = vma;
229	} else {
230		mm->mmap = vma;
231		if (rb_parent)
232			next = rb_entry(rb_parent,
233					struct vm_area_struct, vm_rb);
234		else
235			next = NULL;
236	}
237	vma->vm_next = next;
238	if (next)
239		next->vm_prev = vma;
240}
241
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
242#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
243void arch_pick_mmap_layout(struct mm_struct *mm)
244{
245	mm->mmap_base = TASK_UNMAPPED_BASE;
246	mm->get_unmapped_area = arch_get_unmapped_area;
247	mm->unmap_area = arch_unmap_area;
248}
249#endif
250
251/*
252 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
253 * back to the regular GUP.
254 * If the architecture not support this function, simply return with no
255 * page pinned
256 */
257int __attribute__((weak)) __get_user_pages_fast(unsigned long start,
258				 int nr_pages, int write, struct page **pages)
259{
260	return 0;
261}
262EXPORT_SYMBOL_GPL(__get_user_pages_fast);
263
264/**
265 * get_user_pages_fast() - pin user pages in memory
266 * @start:	starting user address
267 * @nr_pages:	number of pages from start to pin
268 * @write:	whether pages will be written to
269 * @pages:	array that receives pointers to the pages pinned.
270 *		Should be at least nr_pages long.
271 *
272 * Returns number of pages pinned. This may be fewer than the number
273 * requested. If nr_pages is 0 or negative, returns 0. If no pages
274 * were pinned, returns -errno.
275 *
276 * get_user_pages_fast provides equivalent functionality to get_user_pages,
277 * operating on current and current->mm, with force=0 and vma=NULL. However
278 * unlike get_user_pages, it must be called without mmap_sem held.
279 *
280 * get_user_pages_fast may take mmap_sem and page table locks, so no
281 * assumptions can be made about lack of locking. get_user_pages_fast is to be
282 * implemented in a way that is advantageous (vs get_user_pages()) when the
283 * user memory area is already faulted in and present in ptes. However if the
284 * pages have to be faulted in, it may turn out to be slightly slower so
285 * callers need to carefully consider what to use. On many architectures,
286 * get_user_pages_fast simply falls back to get_user_pages.
287 */
288int __attribute__((weak)) get_user_pages_fast(unsigned long start,
289				int nr_pages, int write, struct page **pages)
290{
291	struct mm_struct *mm = current->mm;
292	int ret;
293
294	down_read(&mm->mmap_sem);
295	ret = get_user_pages(current, mm, start, nr_pages,
296					write, 0, pages, NULL);
297	up_read(&mm->mmap_sem);
298
299	return ret;
300}
301EXPORT_SYMBOL_GPL(get_user_pages_fast);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
302
303/* Tracepoints definitions. */
304EXPORT_TRACEPOINT_SYMBOL(kmalloc);
305EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
306EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
307EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
308EXPORT_TRACEPOINT_SYMBOL(kfree);
309EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
v3.15
  1#include <linux/mm.h>
  2#include <linux/slab.h>
  3#include <linux/string.h>
  4#include <linux/compiler.h>
  5#include <linux/export.h>
  6#include <linux/err.h>
  7#include <linux/sched.h>
  8#include <linux/security.h>
  9#include <linux/swap.h>
 10#include <linux/swapops.h>
 11#include <linux/mman.h>
 12#include <linux/hugetlb.h>
 13#include <linux/vmalloc.h>
 14
 15#include <asm/uaccess.h>
 16
 17#include "internal.h"
 18
 19#define CREATE_TRACE_POINTS
 20#include <trace/events/kmem.h>
 21
 22/**
 23 * kstrdup - allocate space for and copy an existing string
 24 * @s: the string to duplicate
 25 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 26 */
 27char *kstrdup(const char *s, gfp_t gfp)
 28{
 29	size_t len;
 30	char *buf;
 31
 32	if (!s)
 33		return NULL;
 34
 35	len = strlen(s) + 1;
 36	buf = kmalloc_track_caller(len, gfp);
 37	if (buf)
 38		memcpy(buf, s, len);
 39	return buf;
 40}
 41EXPORT_SYMBOL(kstrdup);
 42
 43/**
 44 * kstrndup - allocate space for and copy an existing string
 45 * @s: the string to duplicate
 46 * @max: read at most @max chars from @s
 47 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 48 */
 49char *kstrndup(const char *s, size_t max, gfp_t gfp)
 50{
 51	size_t len;
 52	char *buf;
 53
 54	if (!s)
 55		return NULL;
 56
 57	len = strnlen(s, max);
 58	buf = kmalloc_track_caller(len+1, gfp);
 59	if (buf) {
 60		memcpy(buf, s, len);
 61		buf[len] = '\0';
 62	}
 63	return buf;
 64}
 65EXPORT_SYMBOL(kstrndup);
 66
 67/**
 68 * kmemdup - duplicate region of memory
 69 *
 70 * @src: memory region to duplicate
 71 * @len: memory region length
 72 * @gfp: GFP mask to use
 73 */
 74void *kmemdup(const void *src, size_t len, gfp_t gfp)
 75{
 76	void *p;
 77
 78	p = kmalloc_track_caller(len, gfp);
 79	if (p)
 80		memcpy(p, src, len);
 81	return p;
 82}
 83EXPORT_SYMBOL(kmemdup);
 84
 85/**
 86 * memdup_user - duplicate memory region from user space
 87 *
 88 * @src: source address in user space
 89 * @len: number of bytes to copy
 90 *
 91 * Returns an ERR_PTR() on failure.
 92 */
 93void *memdup_user(const void __user *src, size_t len)
 94{
 95	void *p;
 96
 97	/*
 98	 * Always use GFP_KERNEL, since copy_from_user() can sleep and
 99	 * cause pagefault, which makes it pointless to use GFP_NOFS
100	 * or GFP_ATOMIC.
101	 */
102	p = kmalloc_track_caller(len, GFP_KERNEL);
103	if (!p)
104		return ERR_PTR(-ENOMEM);
105
106	if (copy_from_user(p, src, len)) {
107		kfree(p);
108		return ERR_PTR(-EFAULT);
109	}
110
111	return p;
112}
113EXPORT_SYMBOL(memdup_user);
114
115static __always_inline void *__do_krealloc(const void *p, size_t new_size,
116					   gfp_t flags)
117{
118	void *ret;
119	size_t ks = 0;
120
121	if (p)
122		ks = ksize(p);
123
124	if (ks >= new_size)
125		return (void *)p;
126
127	ret = kmalloc_track_caller(new_size, flags);
128	if (ret && p)
129		memcpy(ret, p, ks);
130
131	return ret;
132}
133
134/**
135 * __krealloc - like krealloc() but don't free @p.
136 * @p: object to reallocate memory for.
137 * @new_size: how many bytes of memory are required.
138 * @flags: the type of memory to allocate.
139 *
140 * This function is like krealloc() except it never frees the originally
141 * allocated buffer. Use this if you don't want to free the buffer immediately
142 * like, for example, with RCU.
143 */
144void *__krealloc(const void *p, size_t new_size, gfp_t flags)
145{
 
 
 
146	if (unlikely(!new_size))
147		return ZERO_SIZE_PTR;
148
149	return __do_krealloc(p, new_size, flags);
 
 
 
 
 
 
 
 
150
 
151}
152EXPORT_SYMBOL(__krealloc);
153
154/**
155 * krealloc - reallocate memory. The contents will remain unchanged.
156 * @p: object to reallocate memory for.
157 * @new_size: how many bytes of memory are required.
158 * @flags: the type of memory to allocate.
159 *
160 * The contents of the object pointed to are preserved up to the
161 * lesser of the new and old sizes.  If @p is %NULL, krealloc()
162 * behaves exactly like kmalloc().  If @new_size is 0 and @p is not a
163 * %NULL pointer, the object pointed to is freed.
164 */
165void *krealloc(const void *p, size_t new_size, gfp_t flags)
166{
167	void *ret;
168
169	if (unlikely(!new_size)) {
170		kfree(p);
171		return ZERO_SIZE_PTR;
172	}
173
174	ret = __do_krealloc(p, new_size, flags);
175	if (ret && p != ret)
176		kfree(p);
177
178	return ret;
179}
180EXPORT_SYMBOL(krealloc);
181
182/**
183 * kzfree - like kfree but zero memory
184 * @p: object to free memory of
185 *
186 * The memory of the object @p points to is zeroed before freed.
187 * If @p is %NULL, kzfree() does nothing.
188 *
189 * Note: this function zeroes the whole allocated buffer which can be a good
190 * deal bigger than the requested buffer size passed to kmalloc(). So be
191 * careful when using this function in performance sensitive code.
192 */
193void kzfree(const void *p)
194{
195	size_t ks;
196	void *mem = (void *)p;
197
198	if (unlikely(ZERO_OR_NULL_PTR(mem)))
199		return;
200	ks = ksize(mem);
201	memset(mem, 0, ks);
202	kfree(mem);
203}
204EXPORT_SYMBOL(kzfree);
205
206/*
207 * strndup_user - duplicate an existing string from user space
208 * @s: The string to duplicate
209 * @n: Maximum number of bytes to copy, including the trailing NUL.
210 */
211char *strndup_user(const char __user *s, long n)
212{
213	char *p;
214	long length;
215
216	length = strnlen_user(s, n);
217
218	if (!length)
219		return ERR_PTR(-EFAULT);
220
221	if (length > n)
222		return ERR_PTR(-EINVAL);
223
224	p = memdup_user(s, length);
225
226	if (IS_ERR(p))
227		return p;
228
229	p[length - 1] = '\0';
230
231	return p;
232}
233EXPORT_SYMBOL(strndup_user);
234
235void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
236		struct vm_area_struct *prev, struct rb_node *rb_parent)
237{
238	struct vm_area_struct *next;
239
240	vma->vm_prev = prev;
241	if (prev) {
242		next = prev->vm_next;
243		prev->vm_next = vma;
244	} else {
245		mm->mmap = vma;
246		if (rb_parent)
247			next = rb_entry(rb_parent,
248					struct vm_area_struct, vm_rb);
249		else
250			next = NULL;
251	}
252	vma->vm_next = next;
253	if (next)
254		next->vm_prev = vma;
255}
256
257/* Check if the vma is being used as a stack by this task */
258static int vm_is_stack_for_task(struct task_struct *t,
259				struct vm_area_struct *vma)
260{
261	return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
262}
263
264/*
265 * Check if the vma is being used as a stack.
266 * If is_group is non-zero, check in the entire thread group or else
267 * just check in the current task. Returns the pid of the task that
268 * the vma is stack for.
269 */
270pid_t vm_is_stack(struct task_struct *task,
271		  struct vm_area_struct *vma, int in_group)
272{
273	pid_t ret = 0;
274
275	if (vm_is_stack_for_task(task, vma))
276		return task->pid;
277
278	if (in_group) {
279		struct task_struct *t;
280		rcu_read_lock();
281		if (!pid_alive(task))
282			goto done;
283
284		t = task;
285		do {
286			if (vm_is_stack_for_task(t, vma)) {
287				ret = t->pid;
288				goto done;
289			}
290		} while_each_thread(task, t);
291done:
292		rcu_read_unlock();
293	}
294
295	return ret;
296}
297
298#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
299void arch_pick_mmap_layout(struct mm_struct *mm)
300{
301	mm->mmap_base = TASK_UNMAPPED_BASE;
302	mm->get_unmapped_area = arch_get_unmapped_area;
 
303}
304#endif
305
306/*
307 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
308 * back to the regular GUP.
309 * If the architecture not support this function, simply return with no
310 * page pinned
311 */
312int __weak __get_user_pages_fast(unsigned long start,
313				 int nr_pages, int write, struct page **pages)
314{
315	return 0;
316}
317EXPORT_SYMBOL_GPL(__get_user_pages_fast);
318
319/**
320 * get_user_pages_fast() - pin user pages in memory
321 * @start:	starting user address
322 * @nr_pages:	number of pages from start to pin
323 * @write:	whether pages will be written to
324 * @pages:	array that receives pointers to the pages pinned.
325 *		Should be at least nr_pages long.
326 *
327 * Returns number of pages pinned. This may be fewer than the number
328 * requested. If nr_pages is 0 or negative, returns 0. If no pages
329 * were pinned, returns -errno.
330 *
331 * get_user_pages_fast provides equivalent functionality to get_user_pages,
332 * operating on current and current->mm, with force=0 and vma=NULL. However
333 * unlike get_user_pages, it must be called without mmap_sem held.
334 *
335 * get_user_pages_fast may take mmap_sem and page table locks, so no
336 * assumptions can be made about lack of locking. get_user_pages_fast is to be
337 * implemented in a way that is advantageous (vs get_user_pages()) when the
338 * user memory area is already faulted in and present in ptes. However if the
339 * pages have to be faulted in, it may turn out to be slightly slower so
340 * callers need to carefully consider what to use. On many architectures,
341 * get_user_pages_fast simply falls back to get_user_pages.
342 */
343int __weak get_user_pages_fast(unsigned long start,
344				int nr_pages, int write, struct page **pages)
345{
346	struct mm_struct *mm = current->mm;
347	int ret;
348
349	down_read(&mm->mmap_sem);
350	ret = get_user_pages(current, mm, start, nr_pages,
351					write, 0, pages, NULL);
352	up_read(&mm->mmap_sem);
353
354	return ret;
355}
356EXPORT_SYMBOL_GPL(get_user_pages_fast);
357
358unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
359	unsigned long len, unsigned long prot,
360	unsigned long flag, unsigned long pgoff)
361{
362	unsigned long ret;
363	struct mm_struct *mm = current->mm;
364	unsigned long populate;
365
366	ret = security_mmap_file(file, prot, flag);
367	if (!ret) {
368		down_write(&mm->mmap_sem);
369		ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff,
370				    &populate);
371		up_write(&mm->mmap_sem);
372		if (populate)
373			mm_populate(ret, populate);
374	}
375	return ret;
376}
377
378unsigned long vm_mmap(struct file *file, unsigned long addr,
379	unsigned long len, unsigned long prot,
380	unsigned long flag, unsigned long offset)
381{
382	if (unlikely(offset + PAGE_ALIGN(len) < offset))
383		return -EINVAL;
384	if (unlikely(offset & ~PAGE_MASK))
385		return -EINVAL;
386
387	return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
388}
389EXPORT_SYMBOL(vm_mmap);
390
391void kvfree(const void *addr)
392{
393	if (is_vmalloc_addr(addr))
394		vfree(addr);
395	else
396		kfree(addr);
397}
398EXPORT_SYMBOL(kvfree);
399
400struct address_space *page_mapping(struct page *page)
401{
402	struct address_space *mapping = page->mapping;
403
404	/* This happens if someone calls flush_dcache_page on slab page */
405	if (unlikely(PageSlab(page)))
406		return NULL;
407
408	if (unlikely(PageSwapCache(page))) {
409		swp_entry_t entry;
410
411		entry.val = page_private(page);
412		mapping = swap_address_space(entry);
413	} else if ((unsigned long)mapping & PAGE_MAPPING_ANON)
414		mapping = NULL;
415	return mapping;
416}
417
418int overcommit_ratio_handler(struct ctl_table *table, int write,
419			     void __user *buffer, size_t *lenp,
420			     loff_t *ppos)
421{
422	int ret;
423
424	ret = proc_dointvec(table, write, buffer, lenp, ppos);
425	if (ret == 0 && write)
426		sysctl_overcommit_kbytes = 0;
427	return ret;
428}
429
430int overcommit_kbytes_handler(struct ctl_table *table, int write,
431			     void __user *buffer, size_t *lenp,
432			     loff_t *ppos)
433{
434	int ret;
435
436	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
437	if (ret == 0 && write)
438		sysctl_overcommit_ratio = 0;
439	return ret;
440}
441
442/*
443 * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used
444 */
445unsigned long vm_commit_limit(void)
446{
447	unsigned long allowed;
448
449	if (sysctl_overcommit_kbytes)
450		allowed = sysctl_overcommit_kbytes >> (PAGE_SHIFT - 10);
451	else
452		allowed = ((totalram_pages - hugetlb_total_pages())
453			   * sysctl_overcommit_ratio / 100);
454	allowed += total_swap_pages;
455
456	return allowed;
457}
458
459/**
460 * get_cmdline() - copy the cmdline value to a buffer.
461 * @task:     the task whose cmdline value to copy.
462 * @buffer:   the buffer to copy to.
463 * @buflen:   the length of the buffer. Larger cmdline values are truncated
464 *            to this length.
465 * Returns the size of the cmdline field copied. Note that the copy does
466 * not guarantee an ending NULL byte.
467 */
468int get_cmdline(struct task_struct *task, char *buffer, int buflen)
469{
470	int res = 0;
471	unsigned int len;
472	struct mm_struct *mm = get_task_mm(task);
473	if (!mm)
474		goto out;
475	if (!mm->arg_end)
476		goto out_mm;	/* Shh! No looking before we're done */
477
478	len = mm->arg_end - mm->arg_start;
479
480	if (len > buflen)
481		len = buflen;
482
483	res = access_process_vm(task, mm->arg_start, buffer, len, 0);
484
485	/*
486	 * If the nul at the end of args has been overwritten, then
487	 * assume application is using setproctitle(3).
488	 */
489	if (res > 0 && buffer[res-1] != '\0' && len < buflen) {
490		len = strnlen(buffer, res);
491		if (len < res) {
492			res = len;
493		} else {
494			len = mm->env_end - mm->env_start;
495			if (len > buflen - res)
496				len = buflen - res;
497			res += access_process_vm(task, mm->env_start,
498						 buffer+res, len, 0);
499			res = strnlen(buffer, res);
500		}
501	}
502out_mm:
503	mmput(mm);
504out:
505	return res;
506}
507
508/* Tracepoints definitions. */
509EXPORT_TRACEPOINT_SYMBOL(kmalloc);
510EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
511EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
512EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
513EXPORT_TRACEPOINT_SYMBOL(kfree);
514EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);