change system file

hc

2024-10-09 244b2c5ca8b14627e4a17755e5922221e121c771

 kernel/drivers/net/wireguard/queueing.h
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@@ -119,20 +119,17 @@
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 	return cpu;
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 }
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-/* This function is racy, in the sense that next is unlocked, so it could return
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- * the same CPU twice. A race-free version of this would be to instead store an
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- * atomic sequence number, do an increment-and-return, and then iterate through
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- * every possible CPU until we get to that index -- choose_cpu. However that's
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- * a bit slower, and it doesn't seem like this potential race actually
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- * introduces any performance loss, so we live with it.
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+/* This function is racy, in the sense that it's called while last_cpu is
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+ * unlocked, so it could return the same CPU twice. Adding locking or using
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+ * atomic sequence numbers is slower though, and the consequences of racing are
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+ * harmless, so live with it.
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  */
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-static inline int wg_cpumask_next_online(int *next)
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+static inline int wg_cpumask_next_online(int *last_cpu)
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 {
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-	int cpu = *next;
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-
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-	while (unlikely(!cpumask_test_cpu(cpu, cpu_online_mask)))
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-		cpu = cpumask_next(cpu, cpu_online_mask) % nr_cpumask_bits;
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-	*next = cpumask_next(cpu, cpu_online_mask) % nr_cpumask_bits;
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+	int cpu = cpumask_next(*last_cpu, cpu_online_mask);
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+	if (cpu >= nr_cpu_ids)
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+		cpu = cpumask_first(cpu_online_mask);
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+	*last_cpu = cpu;
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 	return cpu;
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 }
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@@ -161,7 +158,7 @@
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 static inline int wg_queue_enqueue_per_device_and_peer(
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 	struct crypt_queue *device_queue, struct prev_queue *peer_queue,
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-	struct sk_buff *skb, struct workqueue_struct *wq, int *next_cpu)
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+	struct sk_buff *skb, struct workqueue_struct *wq)
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 {
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 	int cpu;
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@@ -175,7 +172,7 @@
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 	/* Then we queue it up in the device queue, which consumes the
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 	 * packet as soon as it can.
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 	 */
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-	cpu = wg_cpumask_next_online(next_cpu);
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+	cpu = wg_cpumask_next_online(&device_queue->last_cpu);
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 	if (unlikely(ptr_ring_produce_bh(&device_queue->ring, skb)))
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 		return -EPIPE;
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 	queue_work_on(cpu, wq, &per_cpu_ptr(device_queue->worker, cpu)->work);