[patch V4 08/12] uaccess: Provide put/get_user_scoped()

[Thomas Gleixner]

Provide conveniance wrappers around scoped user access similiar to
put/get_user(), which reduce the usage sites to:

       if (!get_user_scoped(val, ptr))
       		return -EFAULT;

Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
---
V4: Rename to scoped
---
 include/linux/uaccess.h |   44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -825,6 +825,50 @@ for (bool done = false; !done; done = tr
 #define scoped_user_rw_access(uptr, elbl)				\
 	scoped_user_rw_access_size(uptr, sizeof(*(uptr)), elbl)
 
+/**
+ * get_user_scoped - Read user data with scoped access
+ * @val:	The variable to store the value read from user memory
+ * @usrc:	Pointer to the user space memory to read from
+ *
+ * Return: true if successful, false when faulted
+ */
+#define get_user_scoped(val, usrc)				\
+({								\
+	__label__ efault;					\
+	typeof(usrc) _tmpsrc = usrc;				\
+	bool _ret = true;					\
+								\
+	scoped_user_read_access(_tmpsrc, efault)		\
+		unsafe_get_user(val, _tmpsrc, efault);		\
+	if (0) {						\
+	efault:							\
+		_ret = false;					\
+	}							\
+	_ret;							\
+})
+
+/**
+ * put_user_scoped - Write to user memory with scoped access
+ * @val:	The value to write
+ * @udst:	Pointer to the user space memory to write to
+ *
+ * Return: true if successful, false when faulted
+ */
+#define put_user_scoped(val, udst)				\
+({								\
+	__label__ efault;					\
+	typeof(udst) _tmpdst = udst;				\
+	bool _ret = true;					\
+								\
+	scoped_user_write_access(_tmpdst, efault)		\
+		unsafe_put_user(val, _tmpdst, efault);		\
+	if (0) {						\
+	efault:							\
+		_ret = false;					\
+	}							\
+	_ret;							\
+})
+
 #ifdef CONFIG_HARDENED_USERCOPY
 void __noreturn usercopy_abort(const char *name, const char *detail,
 			       bool to_user, unsigned long offset,