From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=202502 header.b=M62pRFpV; dkim-atps=neutral Received: from mail.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by passt.top (Postfix) with ESMTPS id CBA345A061D for ; Tue, 18 Feb 2025 03:50:25 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202502; t=1739847015; bh=XJxp3Q9y8RYkpJ7+U1YgRSStyQELf58tv272wgLFFgw=; h=From:To:Cc:Subject:Date:From; b=M62pRFpVOxBYNnr463Gfn7SpdBRchaLM9PpwiegcuJNkes/I1caz4VwU9Vf0ia5PS GLksKcWoOemx1E3/ML6Ad4ke3E84RD9KxEyUgWGsAQp4tuI1t4RzVx87z6fuWHLHiv Y5x5pwuSPrp0q64dw2dVioHstw4hRgtABVIgk4zPFfpXKz9CFqQiYMG7JYJlqDSIbg AQA23E4d2GKbm+zugEemwR/8hQ2pBUooxwwvXuvkJ89QtGbmuv2QOFUXCrPM+7W63A 5tChzLYrWDOuOCQqYcXFGnYsMj1IFNxMIrsb5ItNAvDGfJih8iSJFhpBMuykkqAWYB hJeqf+jkQ+t4w== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4YxkXR3BTDz4wyw; Tue, 18 Feb 2025 13:50:15 +1100 (AEDT) From: David Gibson To: Stefano Brivio , passt-dev@passt.top Subject: [PATCH] tcp_vu: head_cnt need not be global Date: Tue, 18 Feb 2025 13:50:13 +1100 Message-ID: <20250218025013.1035148-1-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.48.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: O7D6HH2ANJT4UQ4D7YIWYTYFMUJ7DCN3 X-Message-ID-Hash: O7D6HH2ANJT4UQ4D7YIWYTYFMUJ7DCN3 X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: David Gibson , Laurent Vivier X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: head_cnt is a global variable which tracks how many entries in head[] are currently used. The fact that it's global obscures the fact that the lifetime over which it has a meaningful value is quite short: a single call to of tcp_vu_data_from_sock(). Make it a local to tcp_vu_data_from_sock() to make that lifetime clearer. We keep the head[] array global for now - although technically it has the same valid lifetime - because it's large enough we might not want to put it on the stack. Cc: Laurent Vivier Signed-off-by: David Gibson --- tcp_vu.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/tcp_vu.c b/tcp_vu.c index 0622f173..6891ed13 100644 --- a/tcp_vu.c +++ b/tcp_vu.c @@ -38,7 +38,6 @@ static struct iovec iov_vu[VIRTQUEUE_MAX_SIZE + 1]; static struct vu_virtq_element elem[VIRTQUEUE_MAX_SIZE]; static int head[VIRTQUEUE_MAX_SIZE + 1]; -static int head_cnt; /** * tcp_vu_hdrlen() - return the size of the header in level 2 frame (TCP) @@ -183,7 +182,7 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags) static ssize_t tcp_vu_sock_recv(const struct ctx *c, const struct tcp_tap_conn *conn, bool v6, uint32_t already_sent, size_t fillsize, - int *iov_cnt) + int *iov_cnt, int *head_cnt) { struct vu_dev *vdev = c->vdev; struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE]; @@ -202,7 +201,7 @@ static ssize_t tcp_vu_sock_recv(const struct ctx *c, vu_init_elem(elem, &iov_vu[1], VIRTQUEUE_MAX_SIZE); elem_cnt = 0; - head_cnt = 0; + *head_cnt = 0; while (fillsize > 0 && elem_cnt < VIRTQUEUE_MAX_SIZE) { struct iovec *iov; size_t frame_size, dlen; @@ -221,7 +220,7 @@ static ssize_t tcp_vu_sock_recv(const struct ctx *c, ASSERT(iov->iov_len >= hdrlen); iov->iov_base = (char *)iov->iov_base + hdrlen; iov->iov_len -= hdrlen; - head[head_cnt++] = elem_cnt; + head[(*head_cnt)++] = elem_cnt; fillsize -= dlen; elem_cnt += cnt; @@ -261,17 +260,18 @@ static ssize_t tcp_vu_sock_recv(const struct ctx *c, len -= iov->iov_len; } /* adjust head count */ - while (head_cnt > 0 && head[head_cnt - 1] >= i) - head_cnt--; + while (*head_cnt > 0 && head[*head_cnt - 1] >= i) + (*head_cnt)--; + /* mark end of array */ - head[head_cnt] = i; + head[*head_cnt] = i; *iov_cnt = i; /* release unused buffers */ vu_queue_rewind(vq, elem_cnt - i); /* restore space for headers in iov */ - for (i = 0; i < head_cnt; i++) { + for (i = 0; i < *head_cnt; i++) { struct iovec *iov = &elem[head[i]].in_sg[0]; iov->iov_base = (char *)iov->iov_base - hdrlen; @@ -357,11 +357,11 @@ int tcp_vu_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn) struct vu_dev *vdev = c->vdev; struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE]; ssize_t len, previous_dlen; + int i, iov_cnt, head_cnt; size_t hdrlen, fillsize; int v6 = CONN_V6(conn); uint32_t already_sent; const uint16_t *check; - int i, iov_cnt; if (!vu_queue_enabled(vq) || !vu_queue_started(vq)) { debug("Got packet, but RX virtqueue not usable yet"); @@ -396,7 +396,8 @@ int tcp_vu_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn) /* collect the buffers from vhost-user and fill them with the * data from the socket */ - len = tcp_vu_sock_recv(c, conn, v6, already_sent, fillsize, &iov_cnt); + len = tcp_vu_sock_recv(c, conn, v6, already_sent, fillsize, + &iov_cnt, &head_cnt); if (len < 0) { if (len != -EAGAIN && len != -EWOULDBLOCK) { tcp_rst(c, conn); -- 2.48.1