Merge tag 'locking-urgent-2024-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fixes from Thomas Gleixner:
 "Two fixes for locking and jump labels:

   - Ensure that the atomic_cmpxchg() conditions are correct and
     evaluating to true on any non-zero value except 1. The missing
     check of the return value leads to inconsisted state of the jump
     label counter.

   - Add a missing type conversion in the paravirt spinlock code which
     makes loongson build again"

* tag 'locking-urgent-2024-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  jump_label: Fix the fix, brown paper bags galore
  locking/pvqspinlock: Correct the type of "old" variable in pv_kick_node()

Author: torvalds

kernel/jump_label.c

@@ -236,7 +236,7 @@ void static_key_disable_cpuslocked(struct static_key *key)
 	}
 
 	jump_label_lock();
-	if (atomic_cmpxchg(&key->enabled, 1, 0))
+	if (atomic_cmpxchg(&key->enabled, 1, 0) == 1)
 		jump_label_update(key);
 	jump_label_unlock();
 }
@@ -289,7 +289,7 @@ static void __static_key_slow_dec_cpuslocked(struct static_key *key)
 		return;
 
 	guard(mutex)(&jump_label_mutex);
-	if (atomic_cmpxchg(&key->enabled, 1, 0))
+	if (atomic_cmpxchg(&key->enabled, 1, 0) == 1)
 		jump_label_update(key);
 	else
 		WARN_ON_ONCE(!static_key_slow_try_dec(key));

kernel/locking/qspinlock_paravirt.h

@@ -357,7 +357,7 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
 static void pv_kick_node(struct qspinlock *lock, struct mcs_spinlock *node)
 {
 	struct pv_node *pn = (struct pv_node *)node;
-	enum vcpu_state old = vcpu_halted;
+	u8 old = vcpu_halted;
 	/*
 	 * If the vCPU is indeed halted, advance its state to match that of
 	 * pv_wait_node(). If OTOH this fails, the vCPU was running and will