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 3FF11377EC5; Wed, 8 Jul 2026 09:59:50 +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=1783504791; cv=none; b=IJ/7VfjBfV6NWyuWlIU9SgaGs1NXQ/WCYmdrrpYrDGrNAcF2QSObKbw0jJR7d9UPw2eKlRhp/Q3nu3JW53l910rUqzy2tdtohyUEl2j1GSO3JuXZj0MqFbg8XndGfVmrGXBphAZxhlyxEcBF8TZNmqQ9y6Eoy2yOK2JesS99/y0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783504791; c=relaxed/simple; bh=JJDqb+QYIrzkUFHCjuAHhY+kICr+yewKLzrGB/+PSeY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=K+Uapd02hAeW9syvGVqPueTmCS0cIbcddUgVjpINR97caARDz+2v1WRFNR+V45thg2Pj7Nni0OSL37JQVN/+QxriMv2w8MU9i2O+kZwbgJ+Zm7zrKWTxMTqyOUAsnTr2HjXV2FDRFhN5snPYMWXRQ9zYO/MjAe12TsrhFWDLwU4= 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=EXsPvVwd; 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="EXsPvVwd" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codeconstruct.com.au; s=2022a; t=1783504788; bh=10byGrDBUYzD4vHT2KKk0ZCCXHuZx1Ictsu4qzZcgms=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=EXsPvVwdAmEdVM3iJ2LPnNajLjP0VpXPB/VgUEAkhSZcgcBsuIEnMv6X+Smu1tbPP VLbEFmhqkNdEMSs7p7CLhdhKZl2D/FVibRTjyywYEbyUl9W3okLtkvjzd0ntJtdLYm qJHIbGMIP5QPH+K6FU6UauBbf3bdKNyBWI3c5WpY4dxatXq5PTYYrqzMkMy+HsRLyT cTzSzl5CEMtb/rg9N0yXyJd1vtMJPyluyP+66hs/3uzrFKiZC1G88eLCZGwq/VoOTl vXu3i2zrStlqCWiIOrffPliovoQrlzfqxK2dNaMSGTdZ3Tq7rTGDT1obt9yRYsPga6 EXQunUtvPfN9Q== Received: by codeconstruct.com.au (Postfix, from userid 10000) id 9BC7866526; Wed, 8 Jul 2026 17:59:48 +0800 (AWST) From: Jeremy Kerr Date: Wed, 08 Jul 2026 17:58:40 +0800 Subject: [PATCH net-next v3 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: <20260708-dev-mctp-usb-1-1-v3-9-9e710155cdbf@codeconstruct.com.au> References: <20260708-dev-mctp-usb-1-1-v3-0-9e710155cdbf@codeconstruct.com.au> In-Reply-To: <20260708-dev-mctp-usb-1-1-v3-0-9e710155cdbf@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 644e7f88ce8b..0507307c875f 100644 --- a/drivers/net/mctp/mctp-usb.c +++ b/drivers/net/mctp/mctp-usb.c @@ -321,7 +321,7 @@ static int mctp_usb_probe(struct usb_interface *intf, usb_set_intfdata(intf, dev); mctp_usblib_rx_init(&dev->rx, le16_to_cpu(ep_in->wMaxPacketSize), false); - 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 dad876c4da68..4131be31db1a 100644 --- a/drivers/net/mctp/mctp-usblib.c +++ b/drivers/net/mctp/mctp-usblib.c @@ -239,7 +239,7 @@ 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, @@ -249,18 +249,19 @@ 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) @@ -349,6 +350,12 @@ 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) @@ -357,11 +364,11 @@ 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); @@ -370,6 +377,7 @@ 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); @@ -434,15 +442,17 @@ 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; } @@ -481,7 +491,7 @@ 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 c8fe22d7f68e..35cc2cc15f9a 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