kernel/2.6.29.6-aldebaran-rt/mm/util.c

   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 <linux/tracepoint.h>
   8 #include <asm/uaccess.h>
   9
  10 /**
  11  * kstrdup - allocate space for and copy an existing string
  12  * @s: the string to duplicate
  13  * @gfp: the GFP mask used in the kmalloc() call when allocating memory
  14  */
  15 char *kstrdup(const char *s, gfp_t gfp)
  16 {
  17         size_t len;
  18         char *buf;
  19
  20         if (!s)
  21                 return NULL;
  22
  23         len = strlen(s) + 1;
  24         buf = kmalloc_track_caller(len, gfp);
  25         if (buf)
  26                 memcpy(buf, s, len);
  27         return buf;
  28 }
  29 EXPORT_SYMBOL(kstrdup);
  30
  31 /**
  32  * kstrndup - allocate space for and copy an existing string
  33  * @s: the string to duplicate
  34  * @max: read at most @max chars from @s
  35  * @gfp: the GFP mask used in the kmalloc() call when allocating memory
  36  */
  37 char *kstrndup(const char *s, size_t max, gfp_t gfp)
  38 {
  39         size_t len;
  40         char *buf;
  41
  42         if (!s)
  43                 return NULL;
  44
  45         len = strnlen(s, max);
  46         buf = kmalloc_track_caller(len+1, gfp);
  47         if (buf) {
  48                 memcpy(buf, s, len);
  49                 buf[len] = '\0';
  50         }
  51         return buf;
  52 }
  53 EXPORT_SYMBOL(kstrndup);
  54
  55 /**
  56  * kmemdup - duplicate region of memory
  57  *
  58  * @src: memory region to duplicate
  59  * @len: memory region length
  60  * @gfp: GFP mask to use
  61  */
  62 void *kmemdup(const void *src, size_t len, gfp_t gfp)
  63 {
  64         void *p;
  65
  66         p = kmalloc_track_caller(len, gfp);
  67         if (p)
  68                 memcpy(p, src, len);
  69         return p;
  70 }
  71 EXPORT_SYMBOL(kmemdup);
  72
  73 /**
  74  * __krealloc - like krealloc() but don't free @p.
  75  * @p: object to reallocate memory for.
  76  * @new_size: how many bytes of memory are required.
  77  * @flags: the type of memory to allocate.
  78  *
  79  * This function is like krealloc() except it never frees the originally
  80  * allocated buffer. Use this if you don't want to free the buffer immediately
  81  * like, for example, with RCU.
  82  */
  83 void *__krealloc(const void *p, size_t new_size, gfp_t flags)
  84 {
  85         void *ret;
  86         size_t ks = 0;
  87
  88         if (unlikely(!new_size))
  89                 return ZERO_SIZE_PTR;
  90
  91         if (p)
  92                 ks = ksize(p);
  93
  94         if (ks >= new_size)
  95                 return (void *)p;
  96
  97         ret = kmalloc_track_caller(new_size, flags);
  98         if (ret && p)
  99                 memcpy(ret, p, ks);
 100
 101         return ret;
 102 }
 103 EXPORT_SYMBOL(__krealloc);
 104
 105 /**
 106  * krealloc - reallocate memory. The contents will remain unchanged.
 107  * @p: object to reallocate memory for.
 108  * @new_size: how many bytes of memory are required.
 109  * @flags: the type of memory to allocate.
 110  *
 111  * The contents of the object pointed to are preserved up to the
 112  * lesser of the new and old sizes.  If @p is %NULL, krealloc()
 113  * behaves exactly like kmalloc().  If @size is 0 and @p is not a
 114  * %NULL pointer, the object pointed to is freed.
 115  */
 116 void *krealloc(const void *p, size_t new_size, gfp_t flags)
 117 {
 118         void *ret;
 119
 120         if (unlikely(!new_size)) {
 121                 kfree(p);
 122                 return ZERO_SIZE_PTR;
 123         }
 124
 125         ret = __krealloc(p, new_size, flags);
 126         if (ret && p != ret)
 127                 kfree(p);
 128
 129         return ret;
 130 }
 131 EXPORT_SYMBOL(krealloc);
 132
 133 /**
 134  * kzfree - like kfree but zero memory
 135  * @p: object to free memory of
 136  *
 137  * The memory of the object @p points to is zeroed before freed.
 138  * If @p is %NULL, kzfree() does nothing.
 139  */
 140 void kzfree(const void *p)
 141 {
 142         size_t ks;
 143         void *mem = (void *)p;
 144
 145         if (unlikely(ZERO_OR_NULL_PTR(mem)))
 146                 return;
 147         ks = ksize(mem);
 148         memset(mem, 0, ks);
 149         kfree(mem);
 150 }
 151 EXPORT_SYMBOL(kzfree);
 152
 153 /*
 154  * strndup_user - duplicate an existing string from user space
 155  * @s: The string to duplicate
 156  * @n: Maximum number of bytes to copy, including the trailing NUL.
 157  */
 158 char *strndup_user(const char __user *s, long n)
 159 {
 160         char *p;
 161         long length;
 162
 163         length = strnlen_user(s, n);
 164
 165         if (!length)
 166                 return ERR_PTR(-EFAULT);
 167
 168         if (length > n)
 169                 return ERR_PTR(-EINVAL);
 170
 171         p = kmalloc(length, GFP_KERNEL);
 172
 173         if (!p)
 174                 return ERR_PTR(-ENOMEM);
 175
 176         if (copy_from_user(p, s, length)) {
 177                 kfree(p);
 178                 return ERR_PTR(-EFAULT);
 179         }
 180
 181         p[length - 1] = '\0';
 182
 183         return p;
 184 }
 185 EXPORT_SYMBOL(strndup_user);
 186
 187 #ifndef HAVE_ARCH_PICK_MMAP_LAYOUT
 188 void arch_pick_mmap_layout(struct mm_struct *mm)
 189 {
 190         mm->mmap_base = TASK_UNMAPPED_BASE;
 191         mm->get_unmapped_area = arch_get_unmapped_area;
 192         mm->unmap_area = arch_unmap_area;
 193 }
 194 #endif
 195
 196 int __attribute__((weak)) get_user_pages_fast(unsigned long start,
 197                                 int nr_pages, int write, struct page **pages)
 198 {
 199         struct mm_struct *mm = current->mm;
 200         int ret;
 201
 202         down_read(&mm->mmap_sem);
 203         ret = get_user_pages(current, mm, start, nr_pages,
 204                                         write, 0, pages, NULL);
 205         up_read(&mm->mmap_sem);
 206
 207         return ret;
 208 }
 209 EXPORT_SYMBOL_GPL(get_user_pages_fast);
 210
 211 /* Tracepoints definitions. */
 212 DEFINE_TRACE(kmalloc);
 213 DEFINE_TRACE(kmem_cache_alloc);
 214 DEFINE_TRACE(kmalloc_node);
 215 DEFINE_TRACE(kmem_cache_alloc_node);
 216 DEFINE_TRACE(kfree);
 217 DEFINE_TRACE(kmem_cache_free);
 218
 219 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
 220 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
 221 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
 222 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
 223 EXPORT_TRACEPOINT_SYMBOL(kfree);
 224 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);