From nobody Sat Feb 7 17:55:16 2026 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B293332D43F; Tue, 11 Nov 2025 08:14:40 +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=1762848882; cv=none; b=HKRz6ECel8j/gMqXNh4iwAGa1PgoenMO84DKzd0oGeAkGYW8uawCRPHtOKhTyYwFG7cqxJXJcP4OdWmRg0hr3RlPUGYBlg8gOw3B/j6b4FFKu1rmGdBMxbSwfDsW6hT+u0rsLZUbJhuqIjBlJJ/jec0AHyeMEcydwXmmefnu3DE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762848882; c=relaxed/simple; bh=1h4gdR+TCSYQGJF48StulHpEy7fFsWRuNP3JneEhd2s=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=sp1GaPNxtjGp4qikzIvN+8udH+I1Q2gDoYZPVylX4jHWqs9Pm1r2uX7zbbWjS8ogp8o4K05ZTK0HFt3ot/BY3JUhZlTnkzi7vYKDEyXNBHxDHWlMtA1F6PXTnuALSQU9p0vnWbTX7dd/Kzvvp4dm51yeMMIzLoVXtsCQfkgSXXM= 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=P7JPprkQ; 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="P7JPprkQ" Received: by linux.microsoft.com (Postfix, from userid 1231) id 76222212AE45; Tue, 11 Nov 2025 00:14:40 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 76222212AE45 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1762848880; bh=kGKvStNQ+JNMppHZ3F98mObNapVsEdbSU4ej1cfRrDE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P7JPprkQxd4EM+oL7Qgwij+7I2VGhGw89iWPfw27Q8Wn2W6ywf/uDak1QJwgxdvO3 RCcUGkuHhnIykI6p1DT9DTfO891nt0zF+fss3b16gbSBEDBxGPK0m8rTanAYyFwtob mcGiyu0jOAQyk4fWBXCFcRk0s6+JsGbDacXrsYCU= 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, ssengar@linux.microsoft.com, ernis@linux.microsoft.com, dipayanroy@linux.microsoft.com, shirazsaleem@microsoft.com, leon@kernel.org, mlevitsk@redhat.com, yury.norov@gmail.com, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, gargaditya@microsoft.com Cc: Aditya Garg Subject: [PATCH net-next v3 1/2] net: mana: Handle SKB if TX SGEs exceed hardware limit Date: Tue, 11 Nov 2025 00:13:00 -0800 Message-Id: <1762848781-357-2-git-send-email-gargaditya@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1762848781-357-1-git-send-email-gargaditya@linux.microsoft.com> References: <1762848781-357-1-git-send-email-gargaditya@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The MANA hardware supports a maximum of 30 scatter-gather entries (SGEs) per TX WQE. Exceeding this limit can cause TX failures. Add ndo_features_check() callback to validate SKB layout before transmission. For GSO SKBs that would exceed the hardware SGE limit, clear NETIF_F_GSO_MASK to enforce software segmentation in the stack. Add a fallback in mana_start_xmit() to linearize non-GSO SKBs that still exceed the SGE limit. Also, Add ethtool counter for SKBs linearized Co-developed-by: Dipayaan Roy Signed-off-by: Dipayaan Roy Signed-off-by: Aditya Garg --- drivers/net/ethernet/microsoft/mana/mana_en.c | 37 ++++++++++++++++++- .../ethernet/microsoft/mana/mana_ethtool.c | 2 + include/net/mana/gdma.h | 6 ++- include/net/mana/mana.h | 1 + 4 files changed, 43 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/et= hernet/microsoft/mana/mana_en.c index cccd5b63cee6..67ae5421f9ee 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_en.c +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c @@ -11,6 +11,7 @@ #include #include #include +#include =20 #include #include @@ -329,6 +330,20 @@ 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 + if (MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES && + skb_shinfo(skb)->nr_frags + 2 > MAX_TX_WQE_SGL_ENTRIES) { + /* GSO skb with Hardware SGE limit exceeded is not expected here + * as they are handled in mana_features_check() callback + */ + if (skb_linearize(skb)) { + netdev_warn_once(ndev, "Failed to linearize skb with nr_frags=3D%d and = is_gso=3D%d\n", + skb_shinfo(skb)->nr_frags, + skb_is_gso(skb)); + goto tx_drop_count; + } + apc->eth_stats.linear_pkt_tx_cnt++; + } + pkg.tx_oob.s_oob.vcq_num =3D cq->gdma_id; pkg.tx_oob.s_oob.vsq_frame =3D txq->vsq_frame; =20 @@ -442,8 +457,6 @@ 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 { @@ -518,6 +531,25 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struc= t net_device *ndev) return NETDEV_TX_OK; } =20 +static netdev_features_t mana_features_check(struct sk_buff *skb, + struct net_device *ndev, + netdev_features_t features) +{ + if (MAX_SKB_FRAGS + 2 > MAX_TX_WQE_SGL_ENTRIES && + skb_shinfo(skb)->nr_frags + 2 > MAX_TX_WQE_SGL_ENTRIES) { + /* Exceeds HW SGE limit. + * GSO case: + * Disable GSO so the stack will software-segment the skb + * into smaller skbs that fit the SGE budget. + * Non-GSO case: + * The xmit path will attempt skb_linearize() as a fallback. + */ + if (skb_is_gso(skb)) + features &=3D ~NETIF_F_GSO_MASK; + } + return features; +} + static void mana_get_stats64(struct net_device *ndev, struct rtnl_link_stats64 *st) { @@ -878,6 +910,7 @@ static const struct net_device_ops mana_devops =3D { .ndo_open =3D mana_open, .ndo_stop =3D mana_close, .ndo_select_queue =3D mana_select_queue, + .ndo_features_check =3D mana_features_check, .ndo_start_xmit =3D mana_start_xmit, .ndo_validate_addr =3D eth_validate_addr, .ndo_get_stats64 =3D mana_get_stats64, diff --git a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c b/drivers/n= et/ethernet/microsoft/mana/mana_ethtool.c index a1afa75a9463..fa5e1a2f06a9 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c +++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c @@ -71,6 +71,8 @@ static const struct mana_stats_desc mana_eth_stats[] =3D { {"tx_cq_err", offsetof(struct mana_ethtool_stats, tx_cqe_err)}, {"tx_cqe_unknown_type", offsetof(struct mana_ethtool_stats, tx_cqe_unknown_type)}, + {"linear_pkt_tx_cnt", offsetof(struct mana_ethtool_stats, + linear_pkt_tx_cnt)}, {"rx_coalesced_err", offsetof(struct mana_ethtool_stats, rx_coalesced_err)}, {"rx_cqe_unknown_type", offsetof(struct mana_ethtool_stats, diff --git a/include/net/mana/gdma.h b/include/net/mana/gdma.h index 637f42485dba..84614ebe0f4c 100644 --- a/include/net/mana/gdma.h +++ b/include/net/mana/gdma.h @@ -592,6 +592,9 @@ enum { #define GDMA_DRV_CAP_FLAG_1_HANDLE_RECONFIG_EQE BIT(17) #define GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE BIT(6) =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 | \ @@ -601,7 +604,8 @@ enum { 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_HW_VPORT_LINK_AWARE) + GDMA_DRV_CAP_FLAG_1_HW_VPORT_LINK_AWARE | \ + 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 8906901535f5..50a532fb30d6 100644 --- a/include/net/mana/mana.h +++ b/include/net/mana/mana.h @@ -404,6 +404,7 @@ struct mana_ethtool_stats { u64 hc_tx_err_gdma; u64 tx_cqe_err; u64 tx_cqe_unknown_type; + u64 linear_pkt_tx_cnt; u64 rx_coalesced_err; u64 rx_cqe_unknown_type; }; --=20 2.43.0 From nobody Sat Feb 7 17:55:16 2026 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D82C032E14A; Tue, 11 Nov 2025 08:14:42 +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=1762848884; cv=none; b=nM5FnaZ3Hh/O4JOCVU8GuJVl7oF047ue2YGpZFJ1JVxmCae7e1Z7IC7Q0TEWjODqLGv1Iv2sVX9FGGcgUGOjFhBfGj4AoOIW6OctJLpKzeqoOUBJW6RbgXCKr0DaM3y/97abNIFk/BF6iStN6VIAyyFn0VWdUqVzCKPg39WgV0A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762848884; c=relaxed/simple; bh=papQpdMxZeZiO6Qt8EOXXoWcGPBUIrAgpmOX1fAOG5Q=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=aYa8lPHP1YUt1OBk6TqA0mRbhRqjGApHux3OFJf4WHDY1mj3ydwFGMA12JXFx1693BmdFaC7Mekg2YtE4RdM0Y4QhL3/3GZqhRDrmnOXUWFk6ZwrN8N+2221lOhPmbPGg7EFvYQVBRs1zTGEzlTkH7lDYXhxxMi+7RtiwX8KFCc= 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=P+CjRbeD; 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="P+CjRbeD" Received: by linux.microsoft.com (Postfix, from userid 1231) id 8DFF2212AE4B; Tue, 11 Nov 2025 00:14:42 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 8DFF2212AE4B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1762848882; bh=T4NA8arxo+rcogMEzVL17or5uDR3MncUC/lGtD/Hn6o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P+CjRbeD4IJ74AlXQL5IEVSDdThbsyK9diqgJLhxKXRlqw6uiwy76aLAgeYvOE8+L vt1nvE9/X854hHkksfeDNluXdVfClT4HMio9HMYo/OFQsaT4/dLISssPrX6sf/IBNp Z2sMVAMqpUFxmeDPPOG3YT+ImPixe+sh88yZ2M/Q= 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, ssengar@linux.microsoft.com, ernis@linux.microsoft.com, dipayanroy@linux.microsoft.com, shirazsaleem@microsoft.com, leon@kernel.org, mlevitsk@redhat.com, yury.norov@gmail.com, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, gargaditya@microsoft.com Cc: Aditya Garg Subject: [PATCH net-next v3 2/2] net: mana: Drop TX skb on post_work_request failure and unmap resources Date: Tue, 11 Nov 2025 00:13:01 -0800 Message-Id: <1762848781-357-3-git-send-email-gargaditya@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1762848781-357-1-git-send-email-gargaditya@linux.microsoft.com> References: <1762848781-357-1-git-send-email-gargaditya@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Drop TX packets when posting the work request fails and ensure DMA mappings are always cleaned up. Signed-off-by: Aditya Garg --- drivers/net/ethernet/microsoft/mana/gdma_main.c | 1 - drivers/net/ethernet/microsoft/mana/mana_en.c | 7 +++---- include/net/mana/mana.h | 1 + 3 files changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/= ethernet/microsoft/mana/gdma_main.c index effe0a2f207a..65dd8060c7f4 100644 --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c @@ -1332,7 +1332,6 @@ int mana_gd_post_work_request(struct gdma_queue *wq, =20 if (wq->monitor_avl_buf && wqe_size > mana_gd_wq_avail_space(wq)) { gc =3D wq->gdma_dev->gdma_context; - dev_err(gc->dev, "unsuccessful flow control!\n"); return -ENOSPC; } =20 diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/et= hernet/microsoft/mana/mana_en.c index 67ae5421f9ee..066d822f68f0 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_en.c +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c @@ -491,9 +491,9 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct= 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; + goto free_sgl_ptr; } =20 err =3D NETDEV_TX_OK; @@ -513,7 +513,6 @@ netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct= net_device *ndev) tx_stats->bytes +=3D len + ((num_gso_seg - 1) * gso_hs); u64_stats_update_end(&tx_stats->syncp); =20 -tx_busy: if (netif_tx_queue_stopped(net_txq) && mana_can_tx(gdma_sq)) { netif_tx_wake_queue(net_txq); apc->eth_stats.wake_queue++; @@ -1679,7 +1678,7 @@ 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/mana.h b/include/net/mana/mana.h index 50a532fb30d6..d05457d3e1ab 100644 --- a/include/net/mana/mana.h +++ b/include/net/mana/mana.h @@ -585,6 +585,7 @@ 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 2.43.0