From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 D550A339387; Fri, 7 Aug 2026 15:34:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786116870; cv=none; b=UNxJZmZOiDUFk/HLKes9uwBXcMxAKPGisfHFF7o/ITYgVJTY/+0aDqWB/k+GIuCJ0YuqrgZwNzmJXJeY+SIM39VHizyuQv3QEc90bCsooDtRaBLFHAVvD/DThS26FDekLYaClRpZixDtuKIG3LMszWlB2x+dy7DujyH8ogzYtus= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786116870; c=relaxed/simple; bh=Bgjdblr+tI9FHgX5LVfnDQE706nyUSOz6aLkRSkeIvQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G8HfIZox2WSE4mYxOuZ/9FDna4H+e3zCyv47ASXAVgAUwOciMHoyzf4ezJpW1MfDR6MGTq+HiP5Ifb6B8I/TxPd4aCdD7u26IbgDQ/ic3mK17rVk50x5R/6cLMznDCrSXG76vOsV+S8+yN01v29JngQRkHidfg6bFyt8kjTEXFU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=J8B0tG55; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="J8B0tG55" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D26F1F000E9; Fri, 7 Aug 2026 15:34:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786116868; bh=xUbr9sH8+pXRgTuEMGvXg6B7P+T7EgTMHw7Ds69i0tc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=J8B0tG55+IkYJi7kgYkywFqw7UTPj51ghfe93YL02ZCa/sTBrzYdao4D80zUcyH4D lDl+OLO0sPdgSr0fpjORvjqI/0uGso80fVjZ1nhD9lUZQytcCt+DfiTJee+1D77Oq7 qufr1dUlRhtBf6soZLSbpGrkGW71ogePLKTpsibk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jason Xing , Maciej Fijalkowski , Stanislav Fomichev , Jakub Kicinski , Sasha Levin Subject: [PATCH 7.1 074/438] xsk: drain continuation descs after overflow in xsk_build_skb() Date: Fri, 7 Aug 2026 16:34:30 +0200 Message-ID: <20260807143429.563249728@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143428.008222056@linuxfoundation.org> References: <20260807143428.008222056@linuxfoundation.org> User-Agent: quilt/0.69 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 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Xing [ Upstream commit bd44a6dcd4248883de90f5dad53ae80066e27096 ] Fix generic xmit path multi-buffer logic when packets are either too big (count of descriptors exceed MAX_SKB_FRAGS) or an invalid descriptor is included in fragmented packet. Introduce xdp_sock::drain_cont and act upon this flag - when it is set, keep on consuming descriptors from AF_XDP Tx ring and put them directly onto Cq. Previously these descriptors were silently lost and could never be reached again. Fixes: cf24f5a5feea ("xsk: add support for AF_XDP multi-buffer on Tx path") Closes: https://lore.kernel.org/all/20260425041726.85FB3C2BCB2@smtp.kernel.org/ Reviewed-by: Jason Xing Co-developed-by: Maciej Fijalkowski # wrapped cq addr submission onto routine Signed-off-by: Maciej Fijalkowski Signed-off-by: Jason Xing Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20260719135609.147823-3-maciej.fijalkowski@intel.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/xdp_sock.h | 1 + net/xdp/xsk.c | 45 +++++++++++++++++++++++++++++++++++++++--- 2 files changed, 43 insertions(+), 3 deletions(-) diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h index ebac60a3d8a17..8b51876efbed1 100644 --- a/include/net/xdp_sock.h +++ b/include/net/xdp_sock.h @@ -80,6 +80,7 @@ struct xdp_sock { * call of __xsk_generic_xmit(). */ struct sk_buff *skb; + bool drain_cont; struct list_head map_list; /* Protects map_list */ diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 0a6203c425766..8dadc39ca81f3 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -736,6 +736,19 @@ static void xsk_cq_submit_addr_locked(struct xsk_buff_pool *pool, spin_unlock_irqrestore(&pool->cq_prod_lock, flags); } +static void xsk_cq_submit_addr_single_locked(struct xsk_buff_pool *pool, + struct xdp_desc *desc) +{ + unsigned long flags; + u32 idx; + + spin_lock_irqsave(&pool->cq_prod_lock, flags); + idx = xskq_get_prod(pool->cq); + xskq_prod_write_addr(pool->cq, idx, desc->addr); + xskq_prod_submit_n(pool->cq, 1); + spin_unlock_irqrestore(&pool->cq_prod_lock, flags); +} + static void xsk_cq_cancel_locked(struct xsk_buff_pool *pool, u32 n) { spin_lock(&pool->cq->cq_cached_prod_lock); @@ -1027,13 +1040,14 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, static int __xsk_generic_xmit(struct sock *sk) { struct xdp_sock *xs = xdp_sk(sk); - bool sent_frame = false; struct xdp_desc desc; struct sk_buff *skb; + u32 cached_cons; u32 max_batch; int err = 0; mutex_lock(&xs->mutex); + cached_cons = xs->tx->cached_cons; /* Since we dropped the RCU read lock, the socket state might have changed. */ if (unlikely(!xsk_is_bound(xs))) { @@ -1062,11 +1076,21 @@ static int __xsk_generic_xmit(struct sock *sk) goto out; } + if (unlikely(xs->drain_cont)) { + xsk_cq_submit_addr_single_locked(xs->pool, &desc); + xs->tx->invalid_descs++; + xskq_cons_release(xs->tx); + xs->drain_cont = xp_mb_desc(&desc); + continue; + } + skb = xsk_build_skb(xs, &desc); if (IS_ERR(skb)) { err = PTR_ERR(skb); if (err != -EOVERFLOW) goto out; + if (xp_mb_desc(&desc)) + xs->drain_cont = true; err = 0; continue; } @@ -1095,18 +1119,33 @@ static int __xsk_generic_xmit(struct sock *sk) goto out; } - sent_frame = true; xs->skb = NULL; } if (xskq_has_descs(xs->tx)) { + bool drain = xs->skb || xs->drain_cont || xp_mb_desc(&desc); + + err = xsk_cq_reserve_locked(xs->pool); + if (err) { + xs->tx->invalid_descs--; + if (xs->skb) + xsk_drop_skb(xs->skb); + xs->drain_cont = drain; + err = -EAGAIN; + goto out; + } + if (xs->skb) xsk_drop_skb(xs->skb); + + xsk_cq_submit_addr_single_locked(xs->pool, &desc); + xskq_cons_release(xs->tx); + xs->drain_cont = xp_mb_desc(&desc); } out: - if (sent_frame) + if (xs->tx->cached_cons != cached_cons) __xsk_tx_release(xs); mutex_unlock(&xs->mutex); -- 2.53.0