diff options
Diffstat (limited to 'mm')
-rw-r--r-- | mm/util.c | 30 |
1 files changed, 30 insertions, 0 deletions
@@ -70,6 +70,36 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp) | |||
70 | EXPORT_SYMBOL(kmemdup); | 70 | EXPORT_SYMBOL(kmemdup); |
71 | 71 | ||
72 | /** | 72 | /** |
73 | * memdup_user - duplicate memory region from user space | ||
74 | * | ||
75 | * @src: source address in user space | ||
76 | * @len: number of bytes to copy | ||
77 | * | ||
78 | * Returns an ERR_PTR() on failure. | ||
79 | */ | ||
80 | void *memdup_user(const void __user *src, size_t len) | ||
81 | { | ||
82 | void *p; | ||
83 | |||
84 | /* | ||
85 | * Always use GFP_KERNEL, since copy_from_user() can sleep and | ||
86 | * cause pagefault, which makes it pointless to use GFP_NOFS | ||
87 | * or GFP_ATOMIC. | ||
88 | */ | ||
89 | p = kmalloc_track_caller(len, GFP_KERNEL); | ||
90 | if (!p) | ||
91 | return ERR_PTR(-ENOMEM); | ||
92 | |||
93 | if (copy_from_user(p, src, len)) { | ||
94 | kfree(p); | ||
95 | return ERR_PTR(-EFAULT); | ||
96 | } | ||
97 | |||
98 | return p; | ||
99 | } | ||
100 | EXPORT_SYMBOL(memdup_user); | ||
101 | |||
102 | /** | ||
73 | * __krealloc - like krealloc() but don't free @p. | 103 | * __krealloc - like krealloc() but don't free @p. |
74 | * @p: object to reallocate memory for. | 104 | * @p: object to reallocate memory for. |
75 | * @new_size: how many bytes of memory are required. | 105 | * @new_size: how many bytes of memory are required. |