From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.13]) (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 5AC012E2EF3; Mon, 22 Sep 2025 15:26:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758554792; cv=none; b=Bz94RuYge/7PQvMddj1V4cFEXfsSAjlshlsDpQA6qMgSNELmdQjPtRb5RHxQ8b9jtp8UDmm4Ms2mylPtw9HJ248cdttzvJlSLuQt98WVdZksram9cqQxFPmBe0WKkgg08sEiojEX4vOGvwrwtsKRMpw0QX8RNyLLEEvY98DWvDo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758554792; c=relaxed/simple; bh=Y4fnleyqyoss5s3md/xjL2CyA4kvaa4yNTBzeIKaYE8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=kciY5wI60uFmCRQ5Vr4r6yEQhj4yvXtJmN24maqYCB+DgFirJXnfrmtaAY5rn//QZ+rbQIXcoui2pnQNA9tnnaulXFc22TPJsQYdOddoZ+qNadK011A0bo4QU0fdwIBEshxAGeda8zlrV1AY7KUX2r/JwyM1Txu1nVwY8LJYX/8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=N0Numu2v; arc=none smtp.client-ip=192.198.163.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="N0Numu2v" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1758554791; x=1790090791; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Y4fnleyqyoss5s3md/xjL2CyA4kvaa4yNTBzeIKaYE8=; b=N0Numu2vvun2JkHeNbf5oChvqD0o7KIf3/9tTdTVBU27DeSLpEogDVFp jn9rGSkFuVVR5jaVpvPkqdPuq52jipEqLqR9ogqTc+5b10hWaoVBcHzwP /rW5ZMP/JUCx35SlVk2eSF95WqTPtkh4JhCy9uiq3Mub8/VL8MMRUDqnb 864PIm8a7sGWY4846ZNpv5gfFxRQ3psR+ZUegALA9wtmn2YZ4IlNed6/e ufGxQmx5bVKI3eVVe7IGWSa3sCwAorzYMypjZPZ5roct/dlnAdXetkt6g N+E5wXjj41lwD7HWuKa2Zfgs5WrWKr0FELI0d1WZcaNwjAzw3oxs4iIj/ A==; X-CSE-ConnectionGUID: ZLAcn+2eR22tBlS4KF69XA== X-CSE-MsgGUID: cFaGar8cTtGOB9PG963FCg== X-IronPort-AV: E=McAfee;i="6800,10657,11561"; a="63449214" X-IronPort-AV: E=Sophos;i="6.18,285,1751266800"; d="scan'208";a="63449214" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Sep 2025 08:26:31 -0700 X-CSE-ConnectionGUID: PVXFiifhSPiRHnmTtk37bQ== X-CSE-MsgGUID: KyDR+kg0R9WK9bn7HBEtIg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,285,1751266800"; d="scan'208";a="207242236" Received: from boxer.igk.intel.com ([10.102.20.173]) by orviesa002.jf.intel.com with ESMTP; 22 Sep 2025 08:26:29 -0700 From: Maciej Fijalkowski To: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org Cc: netdev@vger.kernel.org, magnus.karlsson@intel.com, stfomichev@gmail.com, kerneljasonxing@gmail.com, Maciej Fijalkowski Subject: [PATCH bpf-next 2/3] xsk: remove @first_frag from xsk_build_skb() Date: Mon, 22 Sep 2025 17:25:59 +0200 Message-Id: <20250922152600.2455136-3-maciej.fijalkowski@intel.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20250922152600.2455136-1-maciej.fijalkowski@intel.com> References: <20250922152600.2455136-1-maciej.fijalkowski@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Devices that set IFF_TX_SKB_NO_LINEAR will not execute branch that handles metadata, as we set @first_frag only for !IFF_TX_SKB_NO_LINEAR code in xsk_build_skb(). Same functionality can be achieved with checking if xsk_get_num_desc() returns 0. To replace current usage of @first_frag with XSKCB(skb)->num_descs check, pull out the code from xsk_set_destructor_arg() that initializes sk_buff::cb and call it before skb_store_bits() in branch that creates skb against first processed frag. This so error path has the XSKCB(skb)->num_descs initialized and can free skb in case skb_store_bits() failed. Signed-off-by: Maciej Fijalkowski --- net/xdp/xsk.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 72194f0a3fc0..064238400036 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -605,6 +605,13 @@ static u32 xsk_get_num_desc(struct sk_buff *skb) return XSKCB(skb)->num_descs; } +static void xsk_init_cb(struct sk_buff *skb) +{ + BUILD_BUG_ON(sizeof(struct xsk_addr_head) > sizeof(skb->cb)); + INIT_LIST_HEAD(&XSKCB(skb)->addrs_list); + XSKCB(skb)->num_descs = 0; +} + static void xsk_destruct_skb(struct sk_buff *skb) { struct xsk_tx_metadata_compl *compl = &skb_shinfo(skb)->xsk_meta; @@ -620,9 +627,6 @@ static void xsk_destruct_skb(struct sk_buff *skb) static void xsk_set_destructor_arg(struct sk_buff *skb, u64 addr) { - BUILD_BUG_ON(sizeof(struct xsk_addr_head) > sizeof(skb->cb)); - INIT_LIST_HEAD(&XSKCB(skb)->addrs_list); - XSKCB(skb)->num_descs = 0; skb_shinfo(skb)->destructor_arg = (void *)(uintptr_t)addr; } @@ -672,7 +676,7 @@ static struct sk_buff *xsk_build_skb_zerocopy(struct xdp_sock *xs, return ERR_PTR(err); skb_reserve(skb, hr); - + xsk_init_cb(skb); xsk_set_destructor_arg(skb, desc->addr); } else { xsk_addr = kmem_cache_zalloc(xsk_tx_generic_cache, GFP_KERNEL); @@ -725,7 +729,6 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, struct xsk_tx_metadata *meta = NULL; struct net_device *dev = xs->dev; struct sk_buff *skb = xs->skb; - bool first_frag = false; int err; if (dev->priv_flags & IFF_TX_SKB_NO_LINEAR) { @@ -742,8 +745,6 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, len = desc->len; if (!skb) { - first_frag = true; - hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(dev->needed_headroom)); tr = dev->needed_tailroom; skb = sock_alloc_send_skb(&xs->sk, hr + len + tr, 1, &err); @@ -752,6 +753,7 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, skb_reserve(skb, hr); skb_put(skb, len); + xsk_init_cb(skb); err = skb_store_bits(skb, 0, buffer, len); if (unlikely(err)) @@ -797,7 +799,7 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, list_add_tail(&xsk_addr->addr_node, &XSKCB(skb)->addrs_list); } - if (first_frag && desc->options & XDP_TX_METADATA) { + if (!xsk_get_num_desc(skb) && desc->options & XDP_TX_METADATA) { if (unlikely(xs->pool->tx_metadata_len == 0)) { err = -EINVAL; goto free_err; @@ -839,7 +841,7 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, return skb; free_err: - if (first_frag && skb) + if (skb && !xsk_get_num_desc(skb)) kfree_skb(skb); if (err == -EOVERFLOW) { -- 2.43.0