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7387943fa3
Using `% nr_cpumask_bits` is slow and complicated, and not totally
robust toward dynamic changes to CPU topologies. Rather than storing the
next CPU in the round-robin, just store the last one, and also return
that value. This simplifies the loop drastically into a much more common
pattern.
Fixes: e7096c131e ("net: WireGuard secure network tunnel")
Cc: stable@vger.kernel.org
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Manuel Leiner <manuel.leiner@gmx.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
109 lines
2.7 KiB
C
109 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*/
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#include "queueing.h"
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#include <linux/skb_array.h>
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struct multicore_worker __percpu *
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wg_packet_percpu_multicore_worker_alloc(work_func_t function, void *ptr)
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{
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int cpu;
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struct multicore_worker __percpu *worker = alloc_percpu(struct multicore_worker);
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if (!worker)
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return NULL;
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for_each_possible_cpu(cpu) {
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per_cpu_ptr(worker, cpu)->ptr = ptr;
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INIT_WORK(&per_cpu_ptr(worker, cpu)->work, function);
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}
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return worker;
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}
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int wg_packet_queue_init(struct crypt_queue *queue, work_func_t function,
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unsigned int len)
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{
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int ret;
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memset(queue, 0, sizeof(*queue));
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queue->last_cpu = -1;
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ret = ptr_ring_init(&queue->ring, len, GFP_KERNEL);
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if (ret)
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return ret;
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queue->worker = wg_packet_percpu_multicore_worker_alloc(function, queue);
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if (!queue->worker) {
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ptr_ring_cleanup(&queue->ring, NULL);
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return -ENOMEM;
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}
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return 0;
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}
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void wg_packet_queue_free(struct crypt_queue *queue, bool purge)
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{
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free_percpu(queue->worker);
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WARN_ON(!purge && !__ptr_ring_empty(&queue->ring));
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ptr_ring_cleanup(&queue->ring, purge ? __skb_array_destroy_skb : NULL);
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}
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#define NEXT(skb) ((skb)->prev)
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#define STUB(queue) ((struct sk_buff *)&queue->empty)
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void wg_prev_queue_init(struct prev_queue *queue)
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{
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NEXT(STUB(queue)) = NULL;
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queue->head = queue->tail = STUB(queue);
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queue->peeked = NULL;
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atomic_set(&queue->count, 0);
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BUILD_BUG_ON(
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offsetof(struct sk_buff, next) != offsetof(struct prev_queue, empty.next) -
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offsetof(struct prev_queue, empty) ||
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offsetof(struct sk_buff, prev) != offsetof(struct prev_queue, empty.prev) -
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offsetof(struct prev_queue, empty));
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}
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static void __wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb)
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{
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WRITE_ONCE(NEXT(skb), NULL);
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WRITE_ONCE(NEXT(xchg_release(&queue->head, skb)), skb);
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}
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bool wg_prev_queue_enqueue(struct prev_queue *queue, struct sk_buff *skb)
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{
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if (!atomic_add_unless(&queue->count, 1, MAX_QUEUED_PACKETS))
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return false;
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__wg_prev_queue_enqueue(queue, skb);
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return true;
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}
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struct sk_buff *wg_prev_queue_dequeue(struct prev_queue *queue)
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{
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struct sk_buff *tail = queue->tail, *next = smp_load_acquire(&NEXT(tail));
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if (tail == STUB(queue)) {
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if (!next)
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return NULL;
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queue->tail = next;
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tail = next;
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next = smp_load_acquire(&NEXT(next));
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}
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if (next) {
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queue->tail = next;
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atomic_dec(&queue->count);
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return tail;
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}
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if (tail != READ_ONCE(queue->head))
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return NULL;
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__wg_prev_queue_enqueue(queue, STUB(queue));
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next = smp_load_acquire(&NEXT(tail));
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if (next) {
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queue->tail = next;
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atomic_dec(&queue->count);
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return tail;
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}
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return NULL;
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}
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#undef NEXT
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#undef STUB
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