[PATCH v3 09/15] futex: Add flags2 argument to futex_requeue()

peterz
2023-09-21T20:17:27Z

[-- Attachment #1: peterz-futex2-requeue-flags.patch --]
[-- Type: text/plain, Size: 3988 bytes --]

In order to support mixed size requeue, add a second flags argument to
the internal futex_requeue() function.

No functional change intended.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/futex/futex.h | 5 +++--
kernel/futex/requeue.c | 12 +++++++-----
kernel/futex/syscalls.c | 6 +++---
3 files changed, 13 insertions(+), 10 deletions(-)

Index: linux-2.6/kernel/futex/futex.h
===================================================================
--- linux-2.6.orig/kernel/futex/futex.h
+++ linux-2.6/kernel/futex/futex.h
@@ -328,8 +328,9 @@ extern int futex_wait_requeue_pi(u32 __u
val, ktime_t *abs_time, u32 bitset, u32 __user
*uaddr2);

-extern int futex_requeue(u32 __user *uaddr1, unsigned int flags,
- u32 __user *uaddr2, int nr_wake, int nr_requeue,
+extern int futex_requeue(u32 __user *uaddr1, unsigned int flags1,
+ u32 __user *uaddr2, unsigned int flags2,
+ int nr_wake, int nr_requeue,
u32 *cmpval, int requeue_pi);

extern int __futex_wait(u32 __user *uaddr, unsigned int flags, u32 val,
Index: linux-2.6/kernel/futex/requeue.c
===================================================================
--- linux-2.6.orig/kernel/futex/requeue.c
+++ linux-2.6/kernel/futex/requeue.c
@@ -346,8 +346,9 @@ futex_proxy_trylock_atomic(u32 __user *p
/**
* futex_requeue() - Requeue waiters from uaddr1 to uaddr2
* @uaddr1: source futex user address
- * @flags: futex flags (FLAGS_SHARED, etc.)
+ * @flags1: futex flags (FLAGS_SHARED, etc.)
* @uaddr2: target futex user address
+ * @flags2: futex flags (FLAGS_SHARED, etc.)
* @nr_wake: number of waiters to wake (must be 1 for requeue_pi)
* @nr_requeue: number of waiters to requeue (0-INT_MAX)
* @cmpval: @uaddr1 expected value (or %NULL)
@@ -361,7 +362,8 @@ futex_proxy_trylock_atomic(u32 __user *p
* - >=0 - on success, the number of tasks requeued or woken;
* - <0 - on error
*/
-int futex_requeue(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
+int futex_requeue(u32 __user *uaddr1, unsigned int flags1,
+ u32 __user *uaddr2, unsigned int flags2,
int nr_wake, int nr_requeue, u32 *cmpval, int requeue_pi)
{
union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT;
@@ -424,10 +426,10 @@ int futex_requeue(u32 __user *uaddr1, un
}

retry:
- ret = get_futex_key(uaddr1, flags, &key1, FUTEX_READ);
+ ret = get_futex_key(uaddr1, flags1, &key1, FUTEX_READ);
if (unlikely(ret != 0))
return ret;
- ret = get_futex_key(uaddr2, flags, &key2,
+ ret = get_futex_key(uaddr2, flags2, &key2,
requeue_pi ? FUTEX_WRITE : FUTEX_READ);
if (unlikely(ret != 0))
return ret;
@@ -459,7 +461,7 @@ retry_private:
if (ret)
return ret;

- if (!(flags & FLAGS_SHARED))
+ if (!(flags1 & FLAGS_SHARED))
goto retry_private;

goto retry;
Index: linux-2.6/kernel/futex/syscalls.c
===================================================================
--- linux-2.6.orig/kernel/futex/syscalls.c
+++ linux-2.6/kernel/futex/syscalls.c
@@ -106,9 +106,9 @@ long do_futex(u32 __user *uaddr, int op,
case FUTEX_WAKE_BITSET:
return futex_wake(uaddr, flags, val, val3);
case FUTEX_REQUEUE:
- return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
+ return futex_requeue(uaddr, flags, uaddr2, flags, val, val2, NULL, 0);
case FUTEX_CMP_REQUEUE:
- return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
+ return futex_requeue(uaddr, flags, uaddr2, flags, val, val2, &val3, 0);
case FUTEX_WAKE_OP:
return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
case FUTEX_LOCK_PI:
@@ -125,7 +125,7 @@ long do_futex(u32 __user *uaddr, int op,
return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
uaddr2);
case FUTEX_CMP_REQUEUE_PI:
- return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
+ return futex_requeue(uaddr, flags, uaddr2, flags, val, val2, &val3, 1);
}
return -ENOSYS;
}