From nobody Wed Dec 17 17:46:41 2025 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B44AB1C6B4; Fri, 3 Oct 2025 15:47:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759506446; cv=none; b=W87+3zHm9TEdmq2uXo4+GudTHGp+cswJZQInLEVMYCGrclfUOcuxwjzFyE3WAHsOnY1QynR3FQRYQCPlkqq+KmBSnNBK1abGj82rubuerEkpy6MsxMA1v0lgYaT8QLiU3zBTbOFf9eqPhVXxpp0kqzJBBQ/WlotsqXtw6KXBqN8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759506446; c=relaxed/simple; bh=QeOdkk/HPd8F+lWj3osQlyj0903mD8z9jFN3xWQIL0E=; h=Date:From:To:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=AHWrUFac4qmjwypit5su/bpU2DwvBUoGgcDkeHldsqwIfWMvgNc0onaW5wIXC3wQei1wLJ2RBWDAP/H2V1Pw1yUF+zkIBIp3vXeJNXuz6ZXkVYKK/ArIwbGI2tu/5bZTQb8Q+NWt+dd/KaLigW2Go/7JH4yDYtKZ2pi3oXaBUUA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=qlYiUHkF; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="qlYiUHkF" Received: by linux.microsoft.com (Postfix, from userid 1231) id 474EB211C261; Fri, 3 Oct 2025 08:47:24 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 474EB211C261 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1759506444; bh=pXrCFoiP29LJ+ofNopBlzkuBSlGEqfHo1NT4ymmIUKA=; h=Date:From:To:Subject:From; b=qlYiUHkFqtHJubOJCMK9OZoof82SUso7n1G2o6BzLuNsUoh4LxrK3sJlRHhNNxZiq hAJbqFA//t+eVjeE2c9F3Wh6qE+zdJYbSx/dxYPPZgpLWCUmcLfdjmhjZFem+jK/KO hnej7hLI1LKUWaQOTHaSrr8TeoUByWwaAmJ2FlzI= Date: Fri, 3 Oct 2025 08:47:24 -0700 From: Aditya Garg To: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, longli@microsoft.com, kotaranov@microsoft.com, horms@kernel.org, shradhagupta@linux.microsoft.com, ernis@linux.microsoft.com, dipayanroy@linux.microsoft.com, shirazsaleem@microsoft.com, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, gargaditya@microsoft.com, gargaditya@linux.microsoft.com, ssengar@linux.microsoft.com Subject: [PATCH net-next] net: mana: Linearize SKB if TX SGEs exceeds hardware limit Message-ID: <20251003154724.GA15670@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The MANA hardware supports a maximum of 30 scatter-gather entries (SGEs) per TX WQE. In rare configurations where MAX_SKB_FRAGS + 2 exceeds this limit, the driver drops the skb. Add a check in mana_start_xmit() to detect such cases and linearize the SKB before transmission. Return NETDEV_TX_BUSY only for -ENOSPC from mana_gd_post_work_request(), send other errors to free_sgl_ptr to free resources and record the tx drop. Signed-off-by: Aditya Garg Reviewed-by: Dipayaan Roy --- drivers/net/ethernet/microsoft/mana/mana_en.c | 26 +++++++++++++++---- include/net/mana/gdma.h | 8 +++++- include/net/mana/mana.h | 1 + 3 files changed, 29 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/et= hernet/microsoft/mana/mana_en.c index f4fc86f20213..22605753ca84 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_en.c +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c @@ -20,6 +20,7 @@ =20 #include #include +#include =20 static DEFINE_IDA(mana_adev_ida); =20 @@ -289,6 +290,19 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struc= t net_device *ndev) cq =3D &apc->tx_qp[txq_idx].tx_cq; tx_stats =3D &txq->stats; =20 + BUILD_BUG_ON(MAX_TX_WQE_SGL_ENTRIES !=3D MANA_MAX_TX_WQE_SGL_ENTRIES); + #if (MAX_SKB_FRAGS + 2 > MANA_MAX_TX_WQE_SGL_ENTRIES) + if (skb_shinfo(skb)->nr_frags + 2 > MANA_MAX_TX_WQE_SGL_ENTRIES) { + netdev_info_once(ndev, + "nr_frags %d exceeds max supported sge limit. Attempting skb_lineari= ze\n", + skb_shinfo(skb)->nr_frags); + if (skb_linearize(skb)) { + netdev_warn_once(ndev, "Failed to linearize skb\n"); + goto tx_drop_count; + } + } + #endif + pkg.tx_oob.s_oob.vcq_num =3D cq->gdma_id; pkg.tx_oob.s_oob.vsq_frame =3D txq->vsq_frame; =20 @@ -402,8 +416,6 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct= net_device *ndev) } } =20 - WARN_ON_ONCE(pkg.wqe_req.num_sge > MAX_TX_WQE_SGL_ENTRIES); - if (pkg.wqe_req.num_sge <=3D ARRAY_SIZE(pkg.sgl_array)) { pkg.wqe_req.sgl =3D pkg.sgl_array; } else { @@ -438,9 +450,13 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struc= t net_device *ndev) =20 if (err) { (void)skb_dequeue_tail(&txq->pending_skbs); + mana_unmap_skb(skb, apc); netdev_warn(ndev, "Failed to post TX OOB: %d\n", err); - err =3D NETDEV_TX_BUSY; - goto tx_busy; + if (err =3D=3D -ENOSPC) { + err =3D NETDEV_TX_BUSY; + goto tx_busy; + } + goto free_sgl_ptr; } =20 err =3D NETDEV_TX_OK; @@ -1606,7 +1622,7 @@ static int mana_move_wq_tail(struct gdma_queue *wq, u= 32 num_units) return 0; } =20 -static void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *= apc) +void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *apc) { struct mana_skb_head *ash =3D (struct mana_skb_head *)skb->head; struct gdma_context *gc =3D apc->ac->gdma_dev->gdma_context; diff --git a/include/net/mana/gdma.h b/include/net/mana/gdma.h index 57df78cfbf82..67fab1a5f382 100644 --- a/include/net/mana/gdma.h +++ b/include/net/mana/gdma.h @@ -489,6 +489,8 @@ struct gdma_wqe { #define MAX_TX_WQE_SIZE 512 #define MAX_RX_WQE_SIZE 256 =20 +#define MANA_MAX_TX_WQE_SGL_ENTRIES 30 + #define MAX_TX_WQE_SGL_ENTRIES ((GDMA_MAX_SQE_SIZE - \ sizeof(struct gdma_sge) - INLINE_OOB_SMALL_SIZE) / \ sizeof(struct gdma_sge)) @@ -591,6 +593,9 @@ enum { /* Driver can self reset on FPGA Reconfig EQE notification */ #define GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE BIT(17) =20 +/* Driver supports linearizing the skb when num_sge exceeds hardware limit= */ +#define GDMA_DRV_CAP_FLAG_1_SKB_LINEARIZE BIT(20) + #define GDMA_DRV_CAP_FLAGS1 \ (GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT | \ GDMA_DRV_CAP_FLAG_1_NAPI_WKDONE_FIX | \ @@ -599,7 +604,8 @@ enum { GDMA_DRV_CAP_FLAG_1_DEV_LIST_HOLES_SUP | \ GDMA_DRV_CAP_FLAG_1_DYNAMIC_IRQ_ALLOC_SUPPORT | \ GDMA_DRV_CAP_FLAG_1_SELF_RESET_ON_EQE | \ - GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE) + GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE | \ + GDMA_DRV_CAP_FLAG_1_SKB_LINEARIZE) =20 #define GDMA_DRV_CAP_FLAGS2 0 =20 diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h index 0921485565c0..330e1bb088bb 100644 --- a/include/net/mana/mana.h +++ b/include/net/mana/mana.h @@ -580,6 +580,7 @@ int mana_set_bw_clamp(struct mana_port_context *apc, u3= 2 speed, void mana_query_phy_stats(struct mana_port_context *apc); int mana_pre_alloc_rxbufs(struct mana_port_context *apc, int mtu, int num_= queues); void mana_pre_dealloc_rxbufs(struct mana_port_context *apc); +void mana_unmap_skb(struct sk_buff *skb, struct mana_port_context *apc); =20 extern const struct ethtool_ops mana_ethtool_ops; extern struct dentry *mana_debugfs_root; --=20 2.34.1