From patchwork Tue Jun 15 00:30:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergey Ryazanov X-Patchwork-Id: 12320267 X-Patchwork-Delegate: kuba@kernel.org 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 2BF36C2B9F4 for ; Tue, 15 Jun 2021 00:30:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 000B360FF1 for ; Tue, 15 Jun 2021 00:30:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230229AbhFOAcd (ORCPT ); Mon, 14 Jun 2021 20:32:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230211AbhFOAcc (ORCPT ); Mon, 14 Jun 2021 20:32:32 -0400 Received: from mail-lf1-x12b.google.com (mail-lf1-x12b.google.com [IPv6:2a00:1450:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2D32C061280 for ; Mon, 14 Jun 2021 17:30:28 -0700 (PDT) Received: by mail-lf1-x12b.google.com with SMTP id f30so24011696lfj.1 for ; Mon, 14 Jun 2021 17:30:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=cdp9YxzUFC9kGIUU/5fRFVyTA0S6VIcnorPRw1B//34=; b=qGHoBAdd5afRP+ysBAcia5MeML2sTR9FjF1VBYx9rGSnqqeBFDbgHugCZ3r+AyYNCY gGHs7K+n6MHIbLoh8W1PDEGFz4boCMdBn6AXAhIqryksQJsE4JCPrFh0V77CuMl1spnu zzPzVkOtFTKgnqqti7i7HWRmVFbg3HjDJ/S2ObBOwOSlKx5xH2EMg2UfQo3lwZ0etPtI EZD0tDnW+09aXv4knMm7XCU3dRkWI0YlDs72F8iVore+6pO4468PMoC9N1nGKv6B40Dq 2UFw2mzxMX2n02fB/outCqBM4vrHwyBYmGs7ncUbmFffTNCWvjJGqh18SdnwWK2oWw7i qulA== 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=cdp9YxzUFC9kGIUU/5fRFVyTA0S6VIcnorPRw1B//34=; b=ewxO3Gs4rllnq7IhL3TZSYyMXExdIJ6POIU5/OR15MRUj7nA+hsNwuy4lgUjO2/xKn 2Skif6n6z6Qaxzxm/gaHoVUkI1rTqOmXlw6dBq01NmL3MlrgaaWapk6ErpjytuDMqWVX jejkcKPZN9aPf1f67P1bCY2b14R9xepLC9DoL9iHE90EjKJGetn47kR45ahMffNUDKdc xUdEewgmdDtg3nnNGCIpSOD6D+dv15+c88bFfLosBM6Tx4vxFOaxl2NZrPoxwymFWw7t rPdL6rWJQVmrTIg4q5j+IoSkfw+XNG76YkRsWo0ThAAe4pUjzvycBx24djkzMp/jeU+B Gh2w== X-Gm-Message-State: AOAM53385Muv4ULQLjdfUA0AJc0PQ5bUMfOBJgI8XFkW56gzXTvv42oZ HO5sh+0vued5JSyIdTqQ6gg= X-Google-Smtp-Source: ABdhPJy4GzfjWbsXKuniuP01DeLz0Pk9huyLF7+ziiDOg4a7q3Kp7FtWFlS6QwXK45U7fdLIZhN1tA== X-Received: by 2002:a19:e008:: with SMTP id x8mr14115788lfg.439.1623717027286; Mon, 14 Jun 2021 17:30:27 -0700 (PDT) Received: from rsa-laptop.internal.lan ([217.25.229.52]) by smtp.gmail.com with ESMTPSA id 9sm1635522lfy.41.2021.06.14.17.30.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Jun 2021 17:30:26 -0700 (PDT) From: Sergey Ryazanov To: Loic Poulain , Johannes Berg , "David S. Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org Subject: [PATCH net-next 07/10] wwan: core: no more hold netdev ops owning module Date: Tue, 15 Jun 2021 03:30:13 +0300 Message-Id: <20210615003016.477-8-ryazanov.s.a@gmail.com> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210615003016.477-1-ryazanov.s.a@gmail.com> References: <20210615003016.477-1-ryazanov.s.a@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org The WWAN netdev ops owner holding was used to protect from the unexpected memory disappear. This approach causes a dependency cycle (driver -> core -> driver) and effectively prevents a WWAN driver unloading. E.g. WWAN hwsim could not be unloaded until all simulated devices are removed: ~# modprobe wwan_hwsim devices=2 ~# lsmod | grep wwan wwan_hwsim 16384 2 wwan 20480 1 wwan_hwsim ~# rmmod wwan_hwsim rmmod: ERROR: Module wwan_hwsim is in use ~# echo > /sys/kernel/debug/wwan_hwsim/hwsim0/destroy ~# echo > /sys/kernel/debug/wwan_hwsim/hwsim1/destroy ~# lsmod | grep wwan wwan_hwsim 16384 0 wwan 20480 1 wwan_hwsim ~# rmmod wwan_hwsim For a real device driver this will cause an inability to unload module until a served device is physically detached. Since the last commit we are removing all child netdev(s) when a driver unregister the netdev ops. This allows us to permit the driver unloading, since any sane driver will call ops unregistering on a device deinitialization. So, remove the holding of an ops owner to make it easier to unload a driver module. The owner field has also beed removed from the ops structure as there are no more users of this field. Signed-off-by: Sergey Ryazanov --- drivers/net/mhi/net.c | 1 - drivers/net/wwan/wwan_core.c | 10 ---------- drivers/net/wwan/wwan_hwsim.c | 1 - include/linux/wwan.h | 2 -- 4 files changed, 14 deletions(-) diff --git a/drivers/net/mhi/net.c b/drivers/net/mhi/net.c index 64af1e518484..ebd1dbf0a536 100644 --- a/drivers/net/mhi/net.c +++ b/drivers/net/mhi/net.c @@ -383,7 +383,6 @@ static void mhi_net_dellink(void *ctxt, struct net_device *ndev, } const struct wwan_ops mhi_wwan_ops = { - .owner = THIS_MODULE, .priv_size = sizeof(struct mhi_net_dev), .setup = mhi_net_setup, .newlink = mhi_net_newlink, diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c index 3f04e674cdaa..28590405172c 100644 --- a/drivers/net/wwan/wwan_core.c +++ b/drivers/net/wwan/wwan_core.c @@ -921,11 +921,6 @@ int wwan_register_ops(struct device *parent, const struct wwan_ops *ops, return -EBUSY; } - if (!try_module_get(ops->owner)) { - wwan_remove_dev(wwandev); - return -ENODEV; - } - wwandev->ops = ops; wwandev->ops_ctxt = ctxt; @@ -952,7 +947,6 @@ static int wwan_child_dellink(struct device *dev, void *data) void wwan_unregister_ops(struct device *parent) { struct wwan_device *wwandev = wwan_dev_get_by_parent(parent); - struct module *owner; LIST_HEAD(kill_list); if (WARN_ON(IS_ERR(wwandev))) @@ -968,8 +962,6 @@ void wwan_unregister_ops(struct device *parent) */ put_device(&wwandev->dev); - owner = wwandev->ops->owner; /* Preserve ops owner */ - rtnl_lock(); /* Prevent concurent netdev(s) creation/destroying */ /* Remove all child netdev(s), using batch removing */ @@ -981,8 +973,6 @@ void wwan_unregister_ops(struct device *parent) rtnl_unlock(); - module_put(owner); - wwandev->ops_ctxt = NULL; wwan_remove_dev(wwandev); } diff --git a/drivers/net/wwan/wwan_hwsim.c b/drivers/net/wwan/wwan_hwsim.c index c1e850b9c087..a8582a58a385 100644 --- a/drivers/net/wwan/wwan_hwsim.c +++ b/drivers/net/wwan/wwan_hwsim.c @@ -94,7 +94,6 @@ static void wwan_hwsim_netdev_setup(struct net_device *ndev) } static const struct wwan_ops wwan_hwsim_wwan_rtnl_ops = { - .owner = THIS_MODULE, .priv_size = 0, /* No private data */ .setup = wwan_hwsim_netdev_setup, }; diff --git a/include/linux/wwan.h b/include/linux/wwan.h index 430a3a0817de..656a571b52ed 100644 --- a/include/linux/wwan.h +++ b/include/linux/wwan.h @@ -119,14 +119,12 @@ void *wwan_port_get_drvdata(struct wwan_port *port); /** * struct wwan_ops - WWAN device ops - * @owner: module owner of the WWAN ops * @priv_size: size of private netdev data area * @setup: set up a new netdev * @newlink: register the new netdev * @dellink: remove the given netdev */ struct wwan_ops { - struct module *owner; unsigned int priv_size; void (*setup)(struct net_device *dev); int (*newlink)(void *ctxt, struct net_device *dev,