From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E084C433EF for ; Wed, 18 May 2022 06:35:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231485AbiERGfR (ORCPT ); Wed, 18 May 2022 02:35:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231393AbiERGet (ORCPT ); Wed, 18 May 2022 02:34:49 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2C92E732A for ; Tue, 17 May 2022 23:34:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id DF8E0B81E97 for ; Wed, 18 May 2022 06:34:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87BDFC385A5; Wed, 18 May 2022 06:34:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652855683; bh=6RX38PTogMqBCoxL6IVoMVc9ZZyqDGD+JmwMnqv+PU0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MJA/WcobQ7FWEWeojPA9tZNvbkiY4Io3+IuQh0rxseer0XndVwG+DNHMCXZtr2nqt 7EfsCTJMeZU1LqKGhxlbRaKFqaTlrLL3GJ9U0X88enS44/bRrtf8zooJDQZ81JB+hX 1kF8sa7rsjfc0uylLXiXsMlhb5FoXcGWoujEqUsigxk+5os6zpQhnVdcHCQ0XN+4K7 P9/qc+bsFdPx5VOsFTUQxaZTgEFeWlQqtGFaxmocwQLqTzT57Q8ERk1lpaA45xnuya Aj0KUqsS0S++lBnE3tF5myoSbD6J2uJRTJDmEDW01jRLciBHn/AyO4lnybgMpYg50U HOwszrg3CoMjw== From: Saeed Mahameed To: "David S. Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, Maxim Mikityanskiy , Tariq Toukan , Saeed Mahameed Subject: [net 04/11] net/mlx5e: Wrap mlx5e_trap_napi_poll into rcu_read_lock Date: Tue, 17 May 2022 23:34:20 -0700 Message-Id: <20220518063427.123758-5-saeed@kernel.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220518063427.123758-1-saeed@kernel.org> References: <20220518063427.123758-1-saeed@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Maxim Mikityanskiy The body of mlx5e_napi_poll is wrapped into rcu_read_lock to be able to read the XDP program pointer using rcu_dereference. However, the trap RQ NAPI doesn't use rcu_read_lock, because the trap RQ works only in the non-linear mode, and mlx5e_skb_from_cqe_nonlinear, until recently, didn't support XDP and didn't call rcu_dereference. Starting from the cited commit, mlx5e_skb_from_cqe_nonlinear supports XDP and calls rcu_dereference, but mlx5e_trap_napi_poll doesn't wrap it into rcu_read_lock. It leads to RCU-lockdep warnings like this: WARNING: suspicious RCU usage This commit fixes the issue by adding an rcu_read_lock to mlx5e_trap_napi_poll, similarly to mlx5e_napi_poll. Fixes: ea5d49bdae8b ("net/mlx5e: Add XDP multi buffer support to the non-linear legacy RQ") Signed-off-by: Maxim Mikityanskiy Reviewed-by: Tariq Toukan Signed-off-by: Saeed Mahameed --- drivers/net/ethernet/mellanox/mlx5/core/en/trap.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c b/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c index a55b066746cb..857840ab1e91 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c @@ -14,19 +14,26 @@ static int mlx5e_trap_napi_poll(struct napi_struct *napi, int budget) bool busy = false; int work_done = 0; + rcu_read_lock(); + ch_stats->poll++; work_done = mlx5e_poll_rx_cq(&rq->cq, budget); busy |= work_done == budget; busy |= rq->post_wqes(rq); - if (busy) - return budget; + if (busy) { + work_done = budget; + goto out; + } if (unlikely(!napi_complete_done(napi, work_done))) - return work_done; + goto out; mlx5e_cq_arm(&rq->cq); + +out: + rcu_read_unlock(); return work_done; } -- 2.36.1