uaccess: Define pagefault lock guard

Define a pagefault lock guard which allows to simplify functions that
need to disable page faults.

Signed-off-by: Viktor Malik <[email protected]>
Link: https://lore.kernel.org/r/8a01beb0b671923976f08297d81242bb2129881d.1750917800.git.vmalik@redhat.com
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: viktormalik

include/linux/uaccess.h

@@ -296,6 +296,8 @@ static inline bool pagefault_disabled(void)
  */
 #define faulthandler_disabled() (pagefault_disabled() || in_atomic())
 
+DEFINE_LOCK_GUARD_0(pagefault, pagefault_disable(), pagefault_enable())
+
 #ifndef CONFIG_ARCH_HAS_SUBPAGE_FAULTS
 
 /**