[RFC][PATCH 08/10] futex: Propagate flags into futex_get_value_locked()

From: Peter Zijlstra
Date: Fri Jul 14 2023 - 10:16:50 EST


In order to facilitate variable sized futexes propagate the flags into
futex_get_value_locked().

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
kernel/futex/core.c | 4 ++--
kernel/futex/futex.h | 2 +-
kernel/futex/pi.c | 8 ++++----
kernel/futex/requeue.c | 4 ++--
kernel/futex/waitwake.c | 4 ++--
5 files changed, 11 insertions(+), 11 deletions(-)

--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -506,12 +506,12 @@ int futex_cmpxchg_value_locked(u32 *curv
return ret;
}

-int futex_get_value_locked(u32 *dest, u32 __user *from)
+int futex_get_value_locked(u32 *dest, u32 __user *from, unsigned int flags)
{
int ret;

pagefault_disable();
- ret = __get_user(*dest, from);
+ ret = futex_get_value(dest, from, flags);
pagefault_enable();

return ret ? -EFAULT : 0;
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -190,7 +190,7 @@ extern void futex_wake_mark(struct wake_

extern int fault_in_user_writeable(u32 __user *uaddr);
extern int futex_cmpxchg_value_locked(u32 *curval, u32 __user *uaddr, u32 uval, u32 newval);
-extern int futex_get_value_locked(u32 *dest, u32 __user *from);
+extern int futex_get_value_locked(u32 *dest, u32 __user *from, unsigned int flags);
extern struct futex_q *futex_top_waiter(struct futex_hash_bucket *hb, union futex_key *key);

extern void __futex_unqueue(struct futex_q *q);
--- a/kernel/futex/pi.c
+++ b/kernel/futex/pi.c
@@ -239,7 +239,7 @@ static int attach_to_pi_state(u32 __user
* still is what we expect it to be, otherwise retry the entire
* operation.
*/
- if (futex_get_value_locked(&uval2, uaddr))
+ if (futex_get_value_locked(&uval2, uaddr, FLAGS_SIZE_32))
goto out_efault;

if (uval != uval2)
@@ -358,7 +358,7 @@ static int handle_exit_race(u32 __user *
* The same logic applies to the case where the exiting task is
* already gone.
*/
- if (futex_get_value_locked(&uval2, uaddr))
+ if (futex_get_value_locked(&uval2, uaddr, FLAGS_SIZE_32))
return -EFAULT;

/* If the user space value has changed, try again. */
@@ -526,7 +526,7 @@ int futex_lock_pi_atomic(u32 __user *uad
* Read the user space value first so we can validate a few
* things before proceeding further.
*/
- if (futex_get_value_locked(&uval, uaddr))
+ if (futex_get_value_locked(&uval, uaddr, FLAGS_SIZE_32))
return -EFAULT;

if (unlikely(should_fail_futex(true)))
@@ -762,7 +762,7 @@ static int __fixup_pi_state_owner(u32 __
if (!pi_state->owner)
newtid |= FUTEX_OWNER_DIED;

- err = futex_get_value_locked(&uval, uaddr);
+ err = futex_get_value_locked(&uval, uaddr, FLAGS_SIZE_32);
if (err)
goto handle_err;

--- a/kernel/futex/requeue.c
+++ b/kernel/futex/requeue.c
@@ -273,7 +273,7 @@ futex_proxy_trylock_atomic(u32 __user *p
u32 curval;
int ret;

- if (futex_get_value_locked(&curval, pifutex))
+ if (futex_get_value_locked(&curval, pifutex, FLAGS_SIZE_32))
return -EFAULT;

if (unlikely(should_fail_futex(true)))
@@ -449,7 +449,7 @@ int futex_requeue(u32 __user *uaddr1, un
if (likely(cmpval != NULL)) {
u32 curval;

- ret = futex_get_value_locked(&curval, uaddr1);
+ ret = futex_get_value_locked(&curval, uaddr1, FLAGS_SIZE_32);

if (unlikely(ret)) {
double_unlock_hb(hb1, hb2);
--- a/kernel/futex/waitwake.c
+++ b/kernel/futex/waitwake.c
@@ -439,7 +439,7 @@ static int futex_wait_multiple_setup(str
u32 val = vs[i].w.val;

hb = futex_q_lock(q);
- ret = futex_get_value_locked(&uval, uaddr);
+ ret = futex_get_value_locked(&uval, uaddr, FLAGS_SIZE_32);

if (!ret && uval == val) {
/*
@@ -607,7 +607,7 @@ int futex_wait_setup(u32 __user *uaddr,
retry_private:
*hb = futex_q_lock(q);

- ret = futex_get_value_locked(&uval, uaddr);
+ ret = futex_get_value_locked(&uval, uaddr, FLAGS_SIZE_32);

if (ret) {
futex_q_unlock(*hb);