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[66.187.233.206]) by smtp.gmail.com with ESMTPSA id j15sm2497542qtv.11.2021.05.27.19.46.37 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 May 2021 19:46:37 -0700 (PDT) From: Hangbin Liu To: bpf@vger.kernel.org Cc: Daniel Borkmann , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , John Fastabend , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Jesper Dangaard Brouer , Hangbin Liu Subject: [PATCH bpf-next] bpf/devmap: remove drops variable from bq_xmit_all() Date: Thu, 27 May 2021 22:43:56 -0400 Message-Id: <20210528024356.24333-1-liuhangbin@gmail.com> X-Mailer: git-send-email 2.18.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As Colin pointed out, the first drops assignment after declaration will be overwritten by the second drops assignment before using, which makes it useless. Since the drops variable will be used only once. Just remove it and use "cnt - sent" in trace_xdp_devmap_xmit() Reported-by: Colin Ian King Fixes: cb261b594b41 ("bpf: Run devmap xdp_prog on flush instead of bulk enqueue") Signed-off-by: Hangbin Liu --- kernel/bpf/devmap.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index f9148daab0e3..2a75e6c2d27d 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -370,8 +370,8 @@ static int dev_map_bpf_prog_run(struct bpf_prog *xdp_prog, static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) { struct net_device *dev = bq->dev; - int sent = 0, drops = 0, err = 0; unsigned int cnt = bq->count; + int sent = 0, err = 0; int to_send = cnt; int i; @@ -388,8 +388,6 @@ static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) to_send = dev_map_bpf_prog_run(bq->xdp_prog, bq->q, cnt, dev); if (!to_send) goto out; - - drops = cnt - to_send; } sent = dev->netdev_ops->ndo_xdp_xmit(dev, to_send, bq->q, flags); @@ -408,9 +406,8 @@ static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) xdp_return_frame_rx_napi(bq->q[i]); out: - drops = cnt - sent; bq->count = 0; - trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, drops, err); + trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, cnt - sent, err); } /* __dev_flush is called from xdp_do_flush() which _must_ be signaled -- 2.26.3