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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 35DC6C11F67 for ; Thu, 1 Jul 2021 07:34:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 10A7561443 for ; Thu, 1 Jul 2021 07:34:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234886AbhGAHg4 (ORCPT ); Thu, 1 Jul 2021 03:36:56 -0400 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:8490 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229906AbhGAHg4 (ORCPT ); Thu, 1 Jul 2021 03:36:56 -0400 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 1617X6Sk001658; Thu, 1 Jul 2021 09:34:17 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=selector1; bh=SSHQUCjcRxi9e5An3G6X83mmduwQejsBAT0L1Ct09B8=; b=ojdxAKW5GCGIg+5cylEW4dy9Pwkf+Zdq8+tnZmcCcjf8gBAJsfJY8xiG58lE2Td5BhGE a8LT4yWnwBDkAWFglQ2f6gawJSw0xZGwUTLv+37FtV9MebN0qA8Z017Q+EGP9s2LP/vQ fphZxvwr9bol9B3440X74Lqad+XZnZWRi0Qfh3ynOkK8G8vsXI/Q3BjlneMLxrH0obQw 4wRppKgispjd+Q708HmdfAjhjM+4rpOB75btdOM93RQgQ/P8cDZCPVrIpDEJnA5SwIPT VVRK11FPx71OUslJb5SyPEs6VrsFGCEUysVodx3NtU9IoewbhWewX0fI3xy4kuL9zAy4 1w== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 39gn11ew0r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 01 Jul 2021 09:34:17 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 6B44010002A; Thu, 1 Jul 2021 09:34:16 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag2node3.st.com [10.75.127.6]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 365BF212FCE; Thu, 1 Jul 2021 09:34:16 +0200 (CEST) Received: from lmecxl0889.lme.st.com (10.75.127.49) by SFHDAG2NODE3.st.com (10.75.127.6) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 1 Jul 2021 09:34:15 +0200 Subject: Re: [PATCH v2 3/4] rpmsg: char: Add possibility to use default endpoint of the rpmsg device. To: Mathieu Poirier CC: Bjorn Andersson , Ohad Ben-Cohen , , , , References: <20210623150504.14450-1-arnaud.pouliquen@foss.st.com> <20210623150504.14450-4-arnaud.pouliquen@foss.st.com> <20210630204823.GC1290178@p14s> From: Arnaud POULIQUEN Message-ID: <18de7b63-7b7a-15d6-0d3d-50409caf0649@foss.st.com> Date: Thu, 1 Jul 2021 09:34:14 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210630204823.GC1290178@p14s> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.49] X-ClientProxiedBy: SFHDAG1NODE2.st.com (10.75.127.2) To SFHDAG2NODE3.st.com (10.75.127.6) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-01_01:2021-06-30,2021-07-01 signatures=0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Mathieu, On 6/30/21 10:48 PM, Mathieu Poirier wrote: > On Wed, Jun 23, 2021 at 05:05:03PM +0200, Arnaud Pouliquen wrote: >> Current implementation create/destroy a new endpoint on each >> rpmsg_eptdev_open/rpmsg_eptdev_release calls. >> >> For a rpmsg device created by the NS announcement mechanism we need to >> use a unique static endpoint that is the default rpmsg device endpoint >> associated to the channel. >> >> This patch prepares the introduction of a rpmsg channel device for the >> char device. The rpmsg channel device will require a default endpoint to >> communicate to the remote processor. >> >> Add the static_ept field in rpmsg_eptdev structure. This boolean >> determines the behavior on rpmsg_eptdev_open and rpmsg_eptdev_release call. >> >> - If static_ept == false: >> Use the legacy behavior by creating a new endpoint each time >> rpmsg_eptdev_open is called and release it when rpmsg_eptdev_release >> is called on /dev/rpmsgX device open/close. >> >> - If static_ept == true: >> use the rpmsg device default endpoint for the communication. >> - Address the update of _rpmsg_chrdev_eptdev_create in e separate patch for readability. >> >> Add protection in rpmsg_eptdev_ioctl to prevent to destroy a default endpoint. >> >> Signed-off-by: Arnaud Pouliquen >> --- >> update vs V1: >> - remove the management of the default endpoint creation from rpmsg_eptdev_open. >> >> --- >> drivers/rpmsg/rpmsg_char.c | 21 +++++++++++++++++++-- >> 1 file changed, 19 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c >> index 50b7d4b00175..a75dce1e29d8 100644 >> --- a/drivers/rpmsg/rpmsg_char.c >> +++ b/drivers/rpmsg/rpmsg_char.c >> @@ -45,6 +45,8 @@ static DEFINE_IDA(rpmsg_minor_ida); >> * @queue_lock: synchronization of @queue operations >> * @queue: incoming message queue >> * @readq: wait object for incoming queue >> + * @static_ept: specify if the endpoint has to be created at each device opening or >> + * if the default endpoint should be used. >> */ >> struct rpmsg_eptdev { >> struct device dev; >> @@ -59,6 +61,8 @@ struct rpmsg_eptdev { >> spinlock_t queue_lock; >> struct sk_buff_head queue; >> wait_queue_head_t readq; >> + >> + bool static_ept; >> }; >> >> int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) >> @@ -116,7 +120,15 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) >> >> get_device(dev); >> >> - ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo); >> + /* >> + * If the static_ept is set to true, the rpmsg device default endpoint is used. >> + * Else a new endpoint is created on open that will be destroyed on release. >> + */ >> + if (eptdev->static_ept) >> + ept = rpdev->ept; >> + else >> + ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo); >> + >> if (!ept) { >> dev_err(dev, "failed to open %s\n", eptdev->chinfo.name); >> put_device(dev); >> @@ -137,7 +149,8 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp) >> /* Close the endpoint, if it's not already destroyed by the parent */ >> mutex_lock(&eptdev->ept_lock); >> if (eptdev->ept) { >> - rpmsg_destroy_ept(eptdev->ept); >> + if (!eptdev->static_ept) >> + rpmsg_destroy_ept(eptdev->ept); >> eptdev->ept = NULL; >> } >> mutex_unlock(&eptdev->ept_lock); >> @@ -264,6 +277,10 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd, >> if (cmd != RPMSG_DESTROY_EPT_IOCTL) >> return -EINVAL; >> >> + /* Don't allow to destroy a default endpoint. */ >> + if (!eptdev->rpdev || eptdev->ept == eptdev->rpdev->ept) > > Did you find a scenario where eptdev->rpdev would not be valid when this is > called? To me if this code is called __rpmsg_chrdev_eptdev_create() has setup > the rpdev pointer and therefore it will be valid. > > If there is a scenario where it is possible that eptdev->rpdev is invalid then > please add a comment with the details. Otherwise simply remove the first part > of the condition. > > Reviewed-by: Mathieu Poirier Good catch! you are right, it seems an over protection, i will verify this making a new revision that will take into account your other remarks. Thanks for all your advices and patchset reviews related to rpmsg_char restructuring. Arnaud > >> + return -EPERM; >> + >> return rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL); >> } >> >> -- >> 2.17.1 >>