From: "Aneesh Kumar K.V" Explicity specify that the caller should pin the user memory otherwise the function will sleep Signed-off-by: Aneesh Kumar K.V Signed-off-by: Andrew Morton --- include/asm-i386/uaccess.h | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff -puN include/asm-i386/uaccess.h~update-__copy_to_user_inatomic include/asm-i386/uaccess.h --- a/include/asm-i386/uaccess.h~update-__copy_to_user_inatomic +++ a/include/asm-i386/uaccess.h @@ -397,7 +397,19 @@ unsigned long __must_check __copy_from_u unsigned long __must_check __copy_from_user_ll_nocache_nozero(void *to, const void __user *from, unsigned long n); -/* +/** + * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. + * @to: Destination address, in user space. + * @from: Source address, in kernel space. + * @n: Number of bytes to copy. + * + * Context: User context only. + * + * Copy data from kernel space to user space. Caller must check + * the specified block with access_ok() before calling this function. + * The caller should also make sure he pins the user space address + * so that the we don't result in page fault and sleep. + * * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault * we return the initial request size (1, 2 or 4), as copy_*_user should do. * If a store crosses a page boundary and gets a fault, the x86 will not write _