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 0BFEFC4332F for ; Thu, 8 Dec 2022 13:19:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229848AbiLHNTy (ORCPT ); Thu, 8 Dec 2022 08:19:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229561AbiLHNTx (ORCPT ); Thu, 8 Dec 2022 08:19:53 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 627C15800D for ; Thu, 8 Dec 2022 05:19:51 -0800 (PST) Received: from dggpemm500007.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NSZQf1NnnzqSgm; Thu, 8 Dec 2022 21:15:38 +0800 (CST) Received: from [10.174.178.174] (10.174.178.174) by dggpemm500007.china.huawei.com (7.185.36.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 8 Dec 2022 21:19:49 +0800 Subject: Re: [PATCH] wifi: rtl8xxxu: don't call dev_kfree_skb() under spin_lock_irqsave() To: Ping-Ke Shih , "Jes.Sorensen@gmail.com" , "kvalo@kernel.org" CC: "linux-wireless@vger.kernel.org" , References: <20221207143738.67721-1-yangyingliang@huawei.com> <0cfea9eaf08446d5a7dfcb85da34dcf2@realtek.com> <594be2636427488785b244e5b5725c95@realtek.com> From: Yang Yingliang Message-ID: <73afbcfa-9486-66ab-58a3-2c4f04d1b4ca@huawei.com> Date: Thu, 8 Dec 2022 21:19:48 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <594be2636427488785b244e5b5725c95@realtek.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [10.174.178.174] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500007.china.huawei.com (7.185.36.183) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On 2022/12/8 9:41, Ping-Ke Shih wrote: >> -----Original Message----- >> From: Yang Yingliang >> Sent: Thursday, December 8, 2022 9:26 AM >> To: Ping-Ke Shih ; Jes.Sorensen@gmail.com; kvalo@kernel.org >> Cc: linux-wireless@vger.kernel.org; yangyingliang@huawei.com >> Subject: Re: [PATCH] wifi: rtl8xxxu: don't call dev_kfree_skb() under spin_lock_irqsave() >> >> >> On 2022/12/8 8:38, Ping-Ke Shih wrote: >>>> -----Original Message----- >>>> From: Yang Yingliang >>>> Sent: Wednesday, December 7, 2022 10:38 PM >>>> To: Jes.Sorensen@gmail.com; kvalo@kernel.org >>>> Cc: linux-wireless@vger.kernel.org >>>> Subject: [PATCH] wifi: rtl8xxxu: don't call dev_kfree_skb() under spin_lock_irqsave() >>>> >>>> It is not allowed to call consume_skb() from hardware interrupt context >>> ^^^^^^^^^^^^^ kfree_skb()? >>> because this patch is to replace dev_kfree_skb(). >>> >>>> or with interrupts being disabled. So replace dev_kfree_skb() with >>>> dev_consume_skb_irq() under spin_lock_irqsave(). Compile tested only. >>>> >>>> Fixes: 26f1fad29ad9 ("New driver: rtl8xxxu (mac80211)") >>>> Signed-off-by: Yang Yingliang >>>> --- >>>> drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c >>>> b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c >>>> index ac641a56efb0..d0600af5bef4 100644 >>>> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c >>>> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c >>>> @@ -5274,7 +5274,7 @@ static void rtl8xxxu_queue_rx_urb(struct rtl8xxxu_priv *priv, >>>> pending = priv->rx_urb_pending_count; >>>> } else { >>>> skb = (struct sk_buff *)rx_urb->urb.context; >>>> - dev_kfree_skb(skb); >>>> + dev_consume_skb_irq(skb); >>> Why not dev_kfree_skb_irq() instead? any reason? >> #define dev_kfree_skb(a)        consume_skb(a) >> dev_kfree_skb() is consume_skb(), so use dev_consume_skb_irq() instead. >> >> static inline void dev_kfree_skb_irq(struct sk_buff *skb) >> { >>         __dev_kfree_skb_irq(skb, SKB_REASON_DROPPED); >> } >> >> static inline void dev_consume_skb_irq(struct sk_buff *skb) >> { >>         __dev_kfree_skb_irq(skb, SKB_REASON_CONSUMED); >> } >> They have different free reasons. >> > It falls into this case because of 'priv->shutdown', so DROPPED reason makes > sense, no? Or I misunderstand the reason? You are right, it's better to use dev_kfree_skb_irq(), because this is called when it's stopped and need to drop the SKB, I will send a v2 to change it. Thanks, Yang > > -- > Ping-Ke >