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 X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D214C49EA5 for ; Wed, 23 Jun 2021 11:13:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 48199610F7 for ; Wed, 23 Jun 2021 11:13:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230272AbhFWLQD (ORCPT ); Wed, 23 Jun 2021 07:16:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:54841 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230234AbhFWLQC (ORCPT ); Wed, 23 Jun 2021 07:16:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624446824; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZRUA/Y9lIwzUgTw5uRoa39eJ4yIyIch6xpJH66I9Qdc=; b=cBV1dY+56IayfjMygaVM6XwcOpfakBGjMPq0+MyBVXYFJO1GFZqL4Y5tMv2uAyKa6N959V oyXd62GJ1aOLuBPoORa5NreVE9+Al8i59DZL89FFL5da7bvBgysE/dsr3hZFFN7I81HD4G hiRlxbVN8+xj6e6O48bWWc0Uh3gRtkk= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-490-khex4e86NEGqwEePj9nchA-1; Wed, 23 Jun 2021 07:13:43 -0400 X-MC-Unique: khex4e86NEGqwEePj9nchA-1 Received: by mail-ed1-f70.google.com with SMTP id ee28-20020a056402291cb0290394a9a0bfaeso1112493edb.6 for ; Wed, 23 Jun 2021 04:13:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ZRUA/Y9lIwzUgTw5uRoa39eJ4yIyIch6xpJH66I9Qdc=; b=V9wdVlMyxJXa20gbRIO3rQF4ciQhRq98Ecu4+Bn+cAsn3GBa24GaKy3opQdiaSXrAo HJFHV57xR5vSiFoSAzE5Y5dsRkbMH8FW9ZEA00qHxYYymAnl9NHqr8Y4X0DA8vHZaJCC mMM8l+dZuFMuabUQFqdx2/HlDabyWTIgC/xKiFMKXbaCtB59XcAv2gOad1QhnX/rJPWZ tx+P/IaPrpRY8AxXsJzEUk/PJGiG4RZoLBOjpn5LwkPTBoO/Vjl8oOieN5+XrZSWtGMb TBtHA1sf14UFoyjgTzavmhdiq6JLFEf5OhmV9jsA2RF5J4KrALbkmAHOlBOfAAtYNpaL m68w== X-Gm-Message-State: AOAM532MjrGV8GjVpdaAwz6oPXJHEuNAkoQfhYjgR7aQc6dggYfsdY2N MmPJi9zUIIhrADwlqjxzAvx9r6xsn87JvNw68Am4LJEyOVW5/IzoNob0ovvZiiKVfyHGQWJjG04 kYpJmiTOM5Q61 X-Received: by 2002:a17:906:34cf:: with SMTP id h15mr9261315ejb.526.1624446821843; Wed, 23 Jun 2021 04:13:41 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwNBQa0CtVLyqSCtU7E+yLdrrdnxdFKoAi4uPGzq58jwGDY1F5UViDRBybswKmPs7D4pY6M7Q== X-Received: by 2002:a17:906:34cf:: with SMTP id h15mr9261282ejb.526.1624446821485; Wed, 23 Jun 2021 04:13:41 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([2a0c:4d80:42:443::2]) by smtp.gmail.com with ESMTPSA id ml14sm3124574ejb.27.2021.06.23.04.13.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Jun 2021 04:13:40 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 6C06218073F; Wed, 23 Jun 2021 13:07:28 +0200 (CEST) From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= To: bpf@vger.kernel.org, netdev@vger.kernel.org Cc: Martin KaFai Lau , Hangbin Liu , Jesper Dangaard Brouer , Magnus Karlsson , "Paul E . McKenney" , Jakub Kicinski , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Ariel Elior , GR-everest-linux-l2@marvell.com Subject: [PATCH bpf-next v4 15/19] qede: remove rcu_read_lock() around XDP program invocation Date: Wed, 23 Jun 2021 13:07:23 +0200 Message-Id: <20210623110727.221922-16-toke@redhat.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210623110727.221922-1-toke@redhat.com> References: <20210623110727.221922-1-toke@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org The qede driver has rcu_read_lock()/rcu_read_unlock() pairs around XDP program invocations. However, the actual lifetime of the objects referred by the XDP program invocation is longer, all the way through to the call to xdp_do_flush(), making the scope of the rcu_read_lock() too small. This turns out to be harmless because it all happens in a single NAPI poll cycle (and thus under local_bh_disable()), but it makes the rcu_read_lock() misleading. Rather than extend the scope of the rcu_read_lock(), just get rid of it entirely. With the addition of RCU annotations to the XDP_REDIRECT map types that take bh execution into account, lockdep even understands this to be safe, so there's really no reason to keep it around. Cc: Ariel Elior Cc: GR-everest-linux-l2@marvell.com Signed-off-by: Toke Høiland-Jørgensen --- drivers/net/ethernet/qlogic/qede/qede_fp.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c index 8e150dd4f899..065e9004598e 100644 --- a/drivers/net/ethernet/qlogic/qede/qede_fp.c +++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c @@ -1089,13 +1089,7 @@ static bool qede_rx_xdp(struct qede_dev *edev, xdp_prepare_buff(&xdp, page_address(bd->data), *data_offset, *len, false); - /* Queues always have a full reset currently, so for the time - * being until there's atomic program replace just mark read - * side for map helpers. - */ - rcu_read_lock(); act = bpf_prog_run_xdp(prog, &xdp); - rcu_read_unlock(); /* Recalculate, as XDP might have changed the headers */ *data_offset = xdp.data - xdp.data_hard_start; -- 2.32.0