From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 512A5265602; Tue, 8 Apr 2025 11:32:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744111930; cv=none; b=s89lOkClHL/xBdrM2Q/aVtjx4OQjgRqwrTZlzgoMcx+f/61Da+rtbbliCJai1KACxTaWKAgzXpEIK6phnhf4xQMg+M/Aj+ySlP5X/mwYzOKnd9aAYiwT1gXlNmvzJvFCn2wcGKQoN3qNo19MD/srRQp5sR9ITZCiK4fJNnkal78= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744111930; c=relaxed/simple; bh=flDltspZppSkBKjW55PMGnJlpPIR3p5CZKgIRb71JPQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dpms94nU1hJPWpGzhOhLG5j7YqJRNipsQyBC6cUUtdrBptobzajC3ANyUX/z0B9+bFUQdMDHAljkJ7EzC3H3b7F0kl+ojOdm8a2XQg1QgxnjhS7fN7RE7J1JHF38zoAQjzw8vKYhUhEZQYKPyFj79Sm89zF+4SupRolfsNSegmg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=v3yGbOpE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="v3yGbOpE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7345BC4CEE5; Tue, 8 Apr 2025 11:32:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744111929; bh=flDltspZppSkBKjW55PMGnJlpPIR3p5CZKgIRb71JPQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=v3yGbOpEIxvGz2EE3StZQQ37i8+19oSdN74JrvCE8d2aBDbyFgcSsKpllivE/H6gg tMiKBoCRytnaZYCo4UgRu2V0TBebyA0TJ31bumlT892sQLUzRbkqaVWhx9NFx/I0ey XMViL9FBkNHTZXfNrUeo6KcUu5itbyfcntzyhuUs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Song Yoong Siang , Martin KaFai Lau , Faizal Rahim , Maciej Fijalkowski , Sasha Levin Subject: [PATCH 6.14 612/731] igc: Refactor empty frame insertion for launch time support Date: Tue, 8 Apr 2025 12:48:29 +0200 Message-ID: <20250408104928.507168542@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104914.247897328@linuxfoundation.org> References: <20250408104914.247897328@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Song Yoong Siang [ Upstream commit f9b53bb13923f0a6ed2e784a35301cfb4c28f4f4 ] Refactor the code for inserting an empty frame into a new function igc_insert_empty_frame(). This change extracts the logic for inserting an empty packet from igc_xmit_frame_ring() into a separate function, allowing it to be reused in future implementations, such as the XDP zero copy transmit function. Remove the igc_desc_unused() checking in igc_init_tx_empty_descriptor() because the number of descriptors needed is guaranteed. Ensure that skb allocation and DMA mapping work for the empty frame, before proceeding to fill in igc_tx_buffer info, context descriptor, and data descriptor. Rate limit the error messages for skb allocation and DMA mapping failures. Update the comment to indicate that the 2 descriptors needed by the empty frame are already taken into consideration in igc_xmit_frame_ring(). Handle the case where the insertion of an empty frame fails and explain the reason behind this handling. Signed-off-by: Song Yoong Siang Signed-off-by: Martin KaFai Lau Reviewed-by: Faizal Rahim Reviewed-by: Maciej Fijalkowski Link: https://patch.msgid.link/20250216093430.957880-5-yoong.siang.song@intel.com Stable-dep-of: d931cf9b38da ("igc: Fix TX drops in XDP ZC") Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/igc/igc_main.c | 82 ++++++++++++++--------- 1 file changed, 50 insertions(+), 32 deletions(-) diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 84307bb7313e0..1bfa71545e371 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -1092,7 +1092,8 @@ static int igc_init_empty_frame(struct igc_ring *ring, dma = dma_map_single(ring->dev, skb->data, size, DMA_TO_DEVICE); if (dma_mapping_error(ring->dev, dma)) { - netdev_err_once(ring->netdev, "Failed to map DMA for TX\n"); + net_err_ratelimited("%s: DMA mapping error for empty frame\n", + netdev_name(ring->netdev)); return -ENOMEM; } @@ -1108,20 +1109,12 @@ static int igc_init_empty_frame(struct igc_ring *ring, return 0; } -static int igc_init_tx_empty_descriptor(struct igc_ring *ring, - struct sk_buff *skb, - struct igc_tx_buffer *first) +static void igc_init_tx_empty_descriptor(struct igc_ring *ring, + struct sk_buff *skb, + struct igc_tx_buffer *first) { union igc_adv_tx_desc *desc; u32 cmd_type, olinfo_status; - int err; - - if (!igc_desc_unused(ring)) - return -EBUSY; - - err = igc_init_empty_frame(ring, first, skb); - if (err) - return err; cmd_type = IGC_ADVTXD_DTYP_DATA | IGC_ADVTXD_DCMD_DEXT | IGC_ADVTXD_DCMD_IFCS | IGC_TXD_DCMD | @@ -1140,8 +1133,6 @@ static int igc_init_tx_empty_descriptor(struct igc_ring *ring, ring->next_to_use++; if (ring->next_to_use == ring->count) ring->next_to_use = 0; - - return 0; } #define IGC_EMPTY_FRAME_SIZE 60 @@ -1567,6 +1558,40 @@ static bool igc_request_tx_tstamp(struct igc_adapter *adapter, struct sk_buff *s return false; } +static int igc_insert_empty_frame(struct igc_ring *tx_ring) +{ + struct igc_tx_buffer *empty_info; + struct sk_buff *empty_skb; + void *data; + int ret; + + empty_info = &tx_ring->tx_buffer_info[tx_ring->next_to_use]; + empty_skb = alloc_skb(IGC_EMPTY_FRAME_SIZE, GFP_ATOMIC); + if (unlikely(!empty_skb)) { + net_err_ratelimited("%s: skb alloc error for empty frame\n", + netdev_name(tx_ring->netdev)); + return -ENOMEM; + } + + data = skb_put(empty_skb, IGC_EMPTY_FRAME_SIZE); + memset(data, 0, IGC_EMPTY_FRAME_SIZE); + + /* Prepare DMA mapping and Tx buffer information */ + ret = igc_init_empty_frame(tx_ring, empty_info, empty_skb); + if (unlikely(ret)) { + dev_kfree_skb_any(empty_skb); + return ret; + } + + /* Prepare advanced context descriptor for empty packet */ + igc_tx_ctxtdesc(tx_ring, 0, false, 0, 0, 0); + + /* Prepare advanced data descriptor for empty packet */ + igc_init_tx_empty_descriptor(tx_ring, empty_skb, empty_info); + + return 0; +} + static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, struct igc_ring *tx_ring) { @@ -1586,6 +1611,7 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, * + 1 desc for skb_headlen/IGC_MAX_DATA_PER_TXD, * + 2 desc gap to keep tail from touching head, * + 1 desc for context descriptor, + * + 2 desc for inserting an empty packet for launch time, * otherwise try next time */ for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) @@ -1605,24 +1631,16 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, launch_time = igc_tx_launchtime(tx_ring, txtime, &first_flag, &insert_empty); if (insert_empty) { - struct igc_tx_buffer *empty_info; - struct sk_buff *empty; - void *data; - - empty_info = &tx_ring->tx_buffer_info[tx_ring->next_to_use]; - empty = alloc_skb(IGC_EMPTY_FRAME_SIZE, GFP_ATOMIC); - if (!empty) - goto done; - - data = skb_put(empty, IGC_EMPTY_FRAME_SIZE); - memset(data, 0, IGC_EMPTY_FRAME_SIZE); - - igc_tx_ctxtdesc(tx_ring, 0, false, 0, 0, 0); - - if (igc_init_tx_empty_descriptor(tx_ring, - empty, - empty_info) < 0) - dev_kfree_skb_any(empty); + /* Reset the launch time if the required empty frame fails to + * be inserted. However, this packet is not dropped, so it + * "dirties" the current Qbv cycle. This ensures that the + * upcoming packet, which is scheduled in the next Qbv cycle, + * does not require an empty frame. This way, the launch time + * continues to function correctly despite the current failure + * to insert the empty frame. + */ + if (igc_insert_empty_frame(tx_ring)) + launch_time = 0; } done: -- 2.39.5