From patchwork Fri Aug 7 11:50:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Maguire X-Patchwork-Id: 1342251 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=oracle.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=oracle.com header.i=@oracle.com header.a=rsa-sha256 header.s=corp-2020-01-29 header.b=eC3rj+Wq; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4BNNxb6VFWz9sTQ for ; Fri, 7 Aug 2020 21:51:47 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728419AbgHGLvq (ORCPT ); Fri, 7 Aug 2020 07:51:46 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:36502 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726293AbgHGLvp (ORCPT ); Fri, 7 Aug 2020 07:51:45 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 077BmC3q067021; Fri, 7 Aug 2020 11:51:00 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2020-01-29; bh=BzRCQKw4HJidRU+uGZjtCmLzqvvN9xHo3BaIpDfHdFI=; b=eC3rj+WqLjibfxMc8cBJn3xQ7T5RWcR9Fi15EaKyTm3zJsjjs7fJmMcg8ohGQvKzdZFJ Og8lRTpa0h4W3dX+/Vh+DsTgo0JKdFbRAyqQBt9xbs7p0reXCUN0OTUAlbaFdghOE3J6 yp3LMKkv3LxUY8/MHjTcUr8fNgemJyml4rNVywNyd1vdX9VHe566w7cOU1QfTRXU7sc7 TgLDBkczJBpfDIPezM9A8O04JcrCm30jQotAMyqXNA8CPmTXBILPQInF5lmA0FNZH6oa SPzgvASaHBWOGA5mxqRCU/p4Vn161eY+rpexvUNPHSbGyl24IKMQenr5bzjMHKjnQicP 7A== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 32r6ep84af-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 07 Aug 2020 11:50:59 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 077BnEcx045454; Fri, 7 Aug 2020 11:50:59 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3020.oracle.com with ESMTP id 32qy8qfmuy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 07 Aug 2020 11:50:59 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 077BosmC014478; Fri, 7 Aug 2020 11:50:54 GMT Received: from localhost.uk.oracle.com (/10.175.183.82) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 07 Aug 2020 04:50:54 -0700 From: Alan Maguire To: ast@kernel.org, daniel@iogearbox.net Cc: kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com, john.fastabend@gmail.com, kpsingh@chromium.org, rostedt@goodmis.org, linux-doc@vger.kernel.org, corbet@lwn.net, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, Alan Maguire Subject: [PATCH bpf] bpf: doc: remove references to warning message when using bpf_trace_printk() Date: Fri, 7 Aug 2020 12:50:29 +0100 Message-Id: <1596801029-32395-1-git-send-email-alan.maguire@oracle.com> X-Mailer: git-send-email 1.8.3.1 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9705 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 spamscore=0 bulkscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008070085 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9705 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 bulkscore=0 malwarescore=0 clxscore=1011 mlxscore=0 priorityscore=1501 adultscore=0 impostorscore=0 lowpriorityscore=0 phishscore=0 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008070085 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The BPF helper bpf_trace_printk() no longer uses trace_printk(); it is now triggers a dedicated trace event. Hence the described warning is no longer present, so remove the discussion of it as it may confuse people. Fixes: ac5a72ea5c89 ("bpf: Use dedicated bpf_trace_printk event instead of trace_printk()") Signed-off-by: Alan Maguire --- Documentation/bpf/bpf_design_QA.rst | 11 ----------- 1 file changed, 11 deletions(-) diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst index 12a246f..2df7b06 100644 --- a/Documentation/bpf/bpf_design_QA.rst +++ b/Documentation/bpf/bpf_design_QA.rst @@ -246,17 +246,6 @@ program is loaded the kernel will print warning message, so this helper is only useful for experiments and prototypes. Tracing BPF programs are root only. -Q: bpf_trace_printk() helper warning ------------------------------------- -Q: When bpf_trace_printk() helper is used the kernel prints nasty -warning message. Why is that? - -A: This is done to nudge program authors into better interfaces when -programs need to pass data to user space. Like bpf_perf_event_output() -can be used to efficiently stream data via perf ring buffer. -BPF maps can be used for asynchronous data sharing between kernel -and user space. bpf_trace_printk() should only be used for debugging. - Q: New functionality via kernel modules? ---------------------------------------- Q: Can BPF functionality such as new program or map types, new