Merge master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb
[pandora-kernel.git] / include / linux / uaccess.h
1 #ifndef __LINUX_UACCESS_H__
2 #define __LINUX_UACCESS_H__
3
4 #include <asm/uaccess.h>
5
6 #ifndef ARCH_HAS_NOCACHE_UACCESS
7
8 static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
9                                 const void __user *from, unsigned long n)
10 {
11         return __copy_from_user_inatomic(to, from, n);
12 }
13
14 static inline unsigned long __copy_from_user_nocache(void *to,
15                                 const void __user *from, unsigned long n)
16 {
17         return __copy_from_user(to, from, n);
18 }
19
20 #endif          /* ARCH_HAS_NOCACHE_UACCESS */
21
22 /**
23  * probe_kernel_address(): safely attempt to read from a location
24  * @addr: address to read from - its type is type typeof(retval)*
25  * @retval: read into this variable
26  *
27  * Safely read from address @addr into variable @revtal.  If a kernel fault
28  * happens, handle that and return -EFAULT.
29  * We ensure that the __get_user() is executed in atomic context so that
30  * do_page_fault() doesn't attempt to take mmap_sem.  This makes
31  * probe_kernel_address() suitable for use within regions where the caller
32  * already holds mmap_sem, or other locks which nest inside mmap_sem.
33  */
34 #define probe_kernel_address(addr, retval)              \
35         ({                                              \
36                 long ret;                               \
37                                                         \
38                 inc_preempt_count();                    \
39                 ret = __get_user(retval, addr);         \
40                 dec_preempt_count();                    \
41                 ret;                                    \
42         })
43
44 #endif          /* __LINUX_UACCESS_H__ */