On 9/12/19 10:50 pm, Christophe Leroy wrote:
-extern unsigned long __clear_user(void __user *addr, unsigned long
size);
+extern unsigned long clear_user_asm(void __user *addr, unsigned long
size);
static inline unsigned long clear_user(void __user *addr, unsigned
long size)
{
@@ -409,12 +409,17 @@ static inline unsigned long clear_user(void
__user *addr, unsigned long size)
might_fault();
if (likely(access_ok(addr, size))) {
allow_write_to_user(addr, size);
- ret = __clear_user(addr, size);
+ ret = clear_user_asm(addr, size);
prevent_write_to_user(addr, size);
}
What about changing the above by the following ?
if (likely(access_ok(addr, size))) ret =
__clear_user(addr, size);
return ret;
}
+static inline unsigned long __clear_user(void __user *addr, unsigned
long size)
+{
+ return clear_user(addr, size);
+}
+
Then
static inline unsigned long __clear_user(void __user *addr, unsigned
long size)
{
allow_write_to_user(addr, size);
ret = clear_user_asm(addr, size);
prevent_write_to_user(addr, size);
return ret;
}
This is exactly the patch I initially wrote, I ran it past mpe privately
and he suggested aliasing clear_user() -> __clear_user() instead, as
there's not much point keeping a separate path around for a single user
for a basically non-existent performance gain.
--
Andrew Donnellan OzLabs, ADL Canberra
[email protected] IBM Australia Limited
