From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from codeconstruct.com.au (pi.codeconstruct.com.au [203.29.241.158]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 843CC36B920; Fri, 24 Jul 2026 05:15:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.29.241.158 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784870161; cv=none; b=BQwmmvf2UAT1v2UISsAzCmynw0/K9VusM/YbxdaLkS5kuPVBziSv5KbpyvEgOZxw/Rv00uibul7svgruJxvMnNC9lbq8p3I/+m9GxYHOC8QU1wUjfYIQVOtaQrDHWXqdJOFz9Aet7zWtkt62ueri7iNG3Lf4W+Cf0FdPcSuGQ/4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784870161; c=relaxed/simple; bh=8QNE4Jg9czPrMfSdZDBYbvsG9uLL8b402gsiedUfdDs=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=AwiJ0i7UTcd6RFPND5iwp1y9417JavVbSK7NEp1NHMvee/EHPA8PAHxQLjiI8A8+OpIekwfqo8pVHxgTSQjtDPHrNONxCsbNuMjzLbBF+YpFSqd/Q78UUl9m45rxOBtXPJ0RdBRf11HTMBRBtgz+XYNQ3u/IULYl8o+LWbWUE90= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codeconstruct.com.au; spf=pass smtp.mailfrom=codeconstruct.com.au; dkim=pass (2048-bit key) header.d=codeconstruct.com.au header.i=@codeconstruct.com.au header.b=e3zZ2z/Q; arc=none smtp.client-ip=203.29.241.158 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codeconstruct.com.au Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codeconstruct.com.au Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codeconstruct.com.au header.i=@codeconstruct.com.au header.b="e3zZ2z/Q" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codeconstruct.com.au; s=2022a; t=1784870143; bh=zQA/lAdWT1G2TPowypQluYQTGVIVqEckouEduuRgadg=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=e3zZ2z/Q34zxc/tJF5dDni8+1StCmvgMr+Jf8Zg0Cw1E9fyyue6KbBPPf+HTLDPSo XS/6N2s7oahq5YUaIYiPJRGkWJyjFD/4NUeNxBf094roOAltT7Wt1W1BBJUE9d1nLT S8CXfRsks3/uqtXgd09G9KUDZzeUo3HlxiQG3jqewoDUNw10cX3aoBqbgt60CnjIra VMCTVJK8Kk3FtYwgEHsiap2FoPCMckUIQ/BnhWu+aShyBCE5k/MEK0kU23jRGphvCL I9c6tE7VSWqgj6C9akGjklg3xIj16Wos55G5vS2jQkKxHQGx05a+6Vo8+RH8tGnsNH Q2NlfOgqIKRzw== Received: by codeconstruct.com.au (Postfix, from userid 10000) id A5B0B66F41; Fri, 24 Jul 2026 13:15:43 +0800 (AWST) From: Jeremy Kerr Date: Fri, 24 Jul 2026 13:15:30 +0800 Subject: [PATCH net-next v5 09/12] net: mctp: usblib: Implement transmit-side packet spanning Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260724-dev-mctp-usb-1-1-v5-9-e66bbba0dbdc@codeconstruct.com.au> References: <20260724-dev-mctp-usb-1-1-v5-0-e66bbba0dbdc@codeconstruct.com.au> In-Reply-To: <20260724-dev-mctp-usb-1-1-v5-0-e66bbba0dbdc@codeconstruct.com.au> To: Matt Johnston , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Greg Kroah-Hartman Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org X-Mailer: b4 0.16-dev Add support for packet spanning as defined in DSP0283 v1.1. With the existing v1.0 implementation of multi-packet transfers, all we need here is to adjust the buffer sizes to suit v1.1. Signed-off-by: Jeremy Kerr --- drivers/net/mctp/mctp-usb.c | 2 +- drivers/net/mctp/mctp-usblib.c | 28 +++++++++++++++++++--------- include/linux/usb/mctp-usb.h | 4 +++- 3 files changed, 23 insertions(+), 11 deletions(-) diff --git a/drivers/net/mctp/mctp-usb.c b/drivers/net/mctp/mctp-usb.c index 439e92722a0a..2240c81cc6e7 100644 --- a/drivers/net/mctp/mctp-usb.c +++ b/drivers/net/mctp/mctp-usb.c @@ -344,7 +344,7 @@ static int mctp_usb_probe(struct usb_interface *intf, false); if (rc) goto err_free_netdev; - mctp_usblib_tx_init(&dev->tx, &tx_ops, dev); + mctp_usblib_tx_init(&dev->tx, &tx_ops, dev, false); init_usb_anchor(&dev->tx_anchor); dev->ep_in = ep_in->bEndpointAddress; diff --git a/drivers/net/mctp/mctp-usblib.c b/drivers/net/mctp/mctp-usblib.c index 2304e33193b5..816a86b26a11 100644 --- a/drivers/net/mctp/mctp-usblib.c +++ b/drivers/net/mctp/mctp-usblib.c @@ -248,7 +248,7 @@ EXPORT_SYMBOL_GPL(mctp_usblib_rx_cancel); struct mctp_usblib_tx_ctx { struct mctp_usblib_tx *tx; struct sk_buff_head skbs; - unsigned int len; + unsigned int buf_len, len; enum mctp_usblib_tx_buf_type { TX_SINGLE, TX_FLAT, @@ -258,18 +258,19 @@ struct mctp_usblib_tx_ctx { void mctp_usblib_tx_init(struct mctp_usblib_tx *tx, const struct mctp_usblib_tx_ops *ops, - void *priv) + void *priv, bool span) { memset(tx, 0, sizeof(*tx)); tx->ops = *ops; tx->priv = priv; + tx->span = span; spin_lock_init(&tx->lock); } EXPORT_SYMBOL_GPL(mctp_usblib_tx_init); static int mctp_usblib_tx_avail(struct mctp_usblib_tx_ctx *ctx) { - return ctx->buf_type == TX_SINGLE ? 0 : MCTP_USB_1_0_XFER_SIZE - ctx->len; + return ctx->buf_type == TX_SINGLE ? 0 : ctx->buf_len - ctx->len; } static bool mctp_usblib_tx_should_send(struct mctp_usblib_tx_ctx *ctx) @@ -358,6 +359,12 @@ void mctp_usblib_tx_fini(struct mctp_usblib_tx *tx) } EXPORT_SYMBOL_GPL(mctp_usblib_tx_fini); +/* Max size of a spanned TX. Since we allocate a separate span buffer, limit + * the tx-time allocations to 4k. Larger packets will be sent as single + * transfers. + */ +static const unsigned int TX_SPAN_MAX = 4096 - sizeof(struct mctp_usblib_tx_ctx); + static struct mctp_usblib_tx_ctx * mctp_usblib_tx_ctx_create(struct mctp_usblib_tx *tx, struct sk_buff *skb, bool single) @@ -366,11 +373,11 @@ mctp_usblib_tx_ctx_create(struct mctp_usblib_tx *tx, struct sk_buff *skb, struct mctp_usblib_tx_ctx *ctx; size_t sz = 0; - if (single) { + if (single || skb->len > TX_SPAN_MAX) { type = TX_SINGLE; } else { type = TX_FLAT; - sz = MCTP_USB_1_0_XFER_SIZE; + sz = tx->span ? TX_SPAN_MAX : MCTP_USB_1_0_XFER_SIZE; } ctx = kzalloc_flex(*ctx, buf, sz, GFP_ATOMIC); @@ -379,6 +386,7 @@ mctp_usblib_tx_ctx_create(struct mctp_usblib_tx *tx, struct sk_buff *skb, ctx->tx = tx; ctx->buf_type = type; + ctx->buf_len = sz; ctx->len = skb->len; skb_queue_head_init(&ctx->skbs); __skb_queue_tail(&ctx->skbs, skb); @@ -443,15 +451,17 @@ EXPORT_SYMBOL_GPL(mctp_usblib_tx_send_complete); * * On error, populates @reason. */ -static int mctp_usblib_tx_skb_prepare(struct sk_buff *skb, +static int mctp_usblib_tx_skb_prepare(struct sk_buff *skb, bool span, enum skb_drop_reason *reason) { + unsigned long plen, max_len; struct mctp_usb_hdr *hdr; - unsigned long plen; int rc; + max_len = span ? MCTP_USB_1_1_PKTLEN_MAX : MCTP_USB_1_0_PKTLEN_MAX; + plen = skb->len; - if (plen + sizeof(*hdr) > MCTP_USB_1_0_PKTLEN_MAX) { + if (plen + sizeof(*hdr) > max_len) { *reason = SKB_DROP_REASON_PKT_TOO_BIG; return -EMSGSIZE; } @@ -490,7 +500,7 @@ int mctp_usblib_tx_push(struct net_device *dev, unsigned long flags; int try = 1, rc; - rc = mctp_usblib_tx_skb_prepare(skb, &reason); + rc = mctp_usblib_tx_skb_prepare(skb, tx->span, &reason); if (rc) { mctp_usblib_tx_stats_single_drop(dev); kfree_skb_reason(skb, reason); diff --git a/include/linux/usb/mctp-usb.h b/include/linux/usb/mctp-usb.h index 2979ddaa4dab..4bb04a371105 100644 --- a/include/linux/usb/mctp-usb.h +++ b/include/linux/usb/mctp-usb.h @@ -81,6 +81,7 @@ struct mctp_usblib_tx_ops { struct mctp_usblib_tx { struct mctp_usblib_tx_ops ops; void *priv; + bool span; /* protects access to cur_ctx */ spinlock_t lock; /* context to which we are adding packets, cleared on send */ @@ -88,7 +89,8 @@ struct mctp_usblib_tx { }; void mctp_usblib_tx_init(struct mctp_usblib_tx *tx, - const struct mctp_usblib_tx_ops *ops, void *priv); + const struct mctp_usblib_tx_ops *ops, void *priv, + bool span); void mctp_usblib_tx_fini(struct mctp_usblib_tx *tx); void *mctp_usblib_tx_ctx_priv(struct mctp_usblib_tx_ctx *tx_ctx); -- 2.47.3