blob: 88ea1bd661c0f5164e37a8415050808fa815808f [file] [log] [blame]
Andrew Morton16d69262008-07-25 19:44:36 -07001#include <linux/mm.h>
Matt Mackall30992c92006-01-08 01:01:43 -08002#include <linux/slab.h>
3#include <linux/string.h>
4#include <linux/module.h>
Davi Arnaut96840aa2006-03-24 03:18:42 -08005#include <linux/err.h>
Adrian Bunk3b8f14b2008-07-26 15:22:28 -07006#include <linux/sched.h>
Davi Arnaut96840aa2006-03-24 03:18:42 -08007#include <asm/uaccess.h>
Matt Mackall30992c92006-01-08 01:01:43 -08008
Namhyung Kim6038def2011-05-24 17:11:22 -07009#include "internal.h"
10
Steven Rostedta8d154b2009-04-10 09:36:00 -040011#define CREATE_TRACE_POINTS
Steven Rostedtad8d75f2009-04-14 19:39:12 -040012#include <trace/events/kmem.h>
Steven Rostedta8d154b2009-04-10 09:36:00 -040013
Matt Mackall30992c92006-01-08 01:01:43 -080014/**
Matt Mackall30992c92006-01-08 01:01:43 -080015 * kstrdup - allocate space for and copy an existing string
Matt Mackall30992c92006-01-08 01:01:43 -080016 * @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;
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -070028 buf = kmalloc_track_caller(len, gfp);
Matt Mackall30992c92006-01-08 01:01:43 -080029 if (buf)
30 memcpy(buf, s, len);
31 return buf;
32}
33EXPORT_SYMBOL(kstrdup);
Davi Arnaut96840aa2006-03-24 03:18:42 -080034
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070035/**
Jeremy Fitzhardinge1e66df32007-07-17 18:37:02 -070036 * 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/**
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070060 * 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
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -070070 p = kmalloc_track_caller(len, gfp);
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070071 if (p)
72 memcpy(p, src, len);
73 return p;
74}
75EXPORT_SYMBOL(kmemdup);
76
Christoph Lameteref2ad802007-07-17 04:03:21 -070077/**
Li Zefan610a77e2009-03-31 15:23:16 -070078 * 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/**
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700108 * __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/**
Christoph Lameteref2ad802007-07-17 04:03:21 -0700140 * 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;
Christoph Lameteref2ad802007-07-17 04:03:21 -0700153
154 if (unlikely(!new_size)) {
155 kfree(p);
Christoph Lameter6cb8f912007-07-17 04:03:22 -0700156 return ZERO_SIZE_PTR;
Christoph Lameteref2ad802007-07-17 04:03:21 -0700157 }
158
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700159 ret = __krealloc(p, new_size, flags);
160 if (ret && p != ret)
Christoph Lameteref2ad802007-07-17 04:03:21 -0700161 kfree(p);
Pekka Enberg93bc4e82008-07-26 17:49:33 -0700162
Christoph Lameteref2ad802007-07-17 04:03:21 -0700163 return ret;
164}
165EXPORT_SYMBOL(krealloc);
166
Johannes Weiner3ef0e5b2009-02-20 15:38:41 -0800167/**
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.
Pekka Enberga234bdc2009-05-31 13:50:38 +0300173 *
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.
Johannes Weiner3ef0e5b2009-02-20 15:38:41 -0800177 */
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
Davi Arnaut96840aa2006-03-24 03:18:42 -0800191/*
192 * strndup_user - duplicate an existing string from user space
Davi Arnaut96840aa2006-03-24 03:18:42 -0800193 * @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
Julia Lawall90d74042010-08-09 17:18:26 -0700209 p = memdup_user(s, length);
Davi Arnaut96840aa2006-03-24 03:18:42 -0800210
Julia Lawall90d74042010-08-09 17:18:26 -0700211 if (IS_ERR(p))
212 return p;
Davi Arnaut96840aa2006-03-24 03:18:42 -0800213
214 p[length - 1] = '\0';
215
216 return p;
217}
218EXPORT_SYMBOL(strndup_user);
Andrew Morton16d69262008-07-25 19:44:36 -0700219
Namhyung Kim6038def2011-05-24 17:11:22 -0700220void __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
David Howellsefc1a3b2010-01-15 17:01:35 -0800242#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
Andrew Morton16d69262008-07-25 19:44:36 -0700243void 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
Rusty Russell912985d2008-08-12 17:52:52 -0500250
Xiao Guangrong45888a02010-08-22 19:08:57 +0800251/*
252 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
253 * back to the regular GUP.
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300254 * If the architecture not support this function, simply return with no
Xiao Guangrong45888a02010-08-22 19:08:57 +0800255 * 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
Andy Grover9de100d2009-04-13 14:40:05 -0700264/**
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 *
Andy Grover9de100d2009-04-13 14:40:05 -0700272 * 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.
Nick Piggind2bf6be2009-06-16 15:31:39 -0700275 *
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.
Andy Grover9de100d2009-04-13 14:40:05 -0700287 */
Rusty Russell912985d2008-08-12 17:52:52 -0500288int __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);
Eduard - Gabriel Munteanuca2b84cb2009-03-23 15:12:24 +0200302
303/* Tracepoints definitions. */
Eduard - Gabriel Munteanuca2b84cb2009-03-23 15:12:24 +0200304EXPORT_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);