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 57282C10DC3 for ; Thu, 7 Dec 2023 06:39:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229459AbjLGGi6 (ORCPT ); Thu, 7 Dec 2023 01:38:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229558AbjLGGiz (ORCPT ); Thu, 7 Dec 2023 01:38:55 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3288ED5C for ; Wed, 6 Dec 2023 22:39:01 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAE8DC433C8; Thu, 7 Dec 2023 06:38:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701931140; bh=oEBuYr2m/+uNNqMOsGkoIUp/xfye7K359HZ6CZXafeA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CWUHQgh/Cs7qos5c4D8/jEGRTYGJjaFlBNTygl4+NOn20GgtnwLQU0JHeS5TQ1gJ3 VUUF8TS4sbVwQSgekupC2VVt6jnRbxPnLxSbeec10i3vCPz+04j01keJDw0NklLEn/ S78TaTT6kgTQVI7/JSJKZEbfPs8sEtMLt0GUJT4v8z+27o/+eKSJN1SYlEoyVygSki 0+GYmHdfp91bOb86/1EuRZ+q/xxPqBJpFnGR726BkHKsgKQhM8zzIM1vcpx3ujvnS1 81yt4ysFl/BwxTG98vfo9Fz/XExL6BWD3yk7WwcK4AmPfD8sNba4c+Yj2Oe3d5hIa6 sao2QRiO6tewg== Date: Thu, 7 Dec 2023 12:08:51 +0530 From: Manivannan Sadhasivam To: Qiang Yu Cc: Manivannan Sadhasivam , quic_jhugo@quicinc.com, mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, quic_cang@quicinc.com, quic_mrana@quicinc.com, Hemant Kumar , Lazarus Motha Subject: Re: [PATCH v4 4/4] bus: mhi: host: Take irqsave lock after TRE is generated Message-ID: <20231207063851.GD2932@thinkpad> References: <1699939661-7385-1-git-send-email-quic_qianyu@quicinc.com> <1699939661-7385-5-git-send-email-quic_qianyu@quicinc.com> <20231124100916.GB4536@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 27, 2023 at 03:19:49PM +0800, Qiang Yu wrote: > > On 11/24/2023 6:09 PM, Manivannan Sadhasivam wrote: > > On Tue, Nov 14, 2023 at 01:27:41PM +0800, Qiang Yu wrote: > > > From: Hemant Kumar > > > > > > If CONFIG_TRACE_IRQFLAGS is enabled, irq will be enabled once __local_bh_ > > > enable_ip is called as part of write_unlock_bh. Hence, let's take irqsave > > "__local_bh_enable_ip" is a function name, so you should not break it. > Thanks for let me know, will note this in following patch. > > > > > lock after TRE is generated to avoid running write_unlock_bh when irqsave > > > lock is held. > > > > > I still don't understand this commit message. Where is the write_unlock_bh() > > being called? > > > > - Mani > Write_unlock_bh() is invoked in mhi_gen_te() > The calling flow is like > mhi_queue >     read_lock_irqsave(&mhi_cntrl->pm_lock, flags) >     mhi_gen_tre >         write_lock_bh(&mhi_chan->lock) >         write_unlock_bh(&mhi_chan->lock)   // Will enable irq if > CONFIG_TRACE_IRQFLAGS is enabled >     read_lock_irqsave(&mhi_cntrl->pm_lock, flags) > > after adding this patch, the calling flow becomes > > mhi_queue >     mhi_gen_tre >         write_lock_bh(&mhi_chan->lock) >         write_unlock_bh(&mhi_chan->lock) >     read_lock_irqsave(&mhi_cntrl->pm_lock, flags) >     read_lock_irqsave(&mhi_cntrl->pm_lock, flags) So this patch essentially fixes the issue caused by patch 1? If so, this should be squashed into patch 1. - Mani > > > > > Signed-off-by: Hemant Kumar > > > Signed-off-by: Lazarus Motha > > > Signed-off-by: Qiang Yu > > > --- > > > drivers/bus/mhi/host/main.c | 13 +++++-------- > > > 1 file changed, 5 insertions(+), 8 deletions(-) > > > > > > diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c > > > index 33f27e2..d7abd0b 100644 > > > --- a/drivers/bus/mhi/host/main.c > > > +++ b/drivers/bus/mhi/host/main.c > > > @@ -1128,17 +1128,15 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info, > > > if (unlikely(MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))) > > > return -EIO; > > > - read_lock_irqsave(&mhi_cntrl->pm_lock, flags); > > > - > > > ret = mhi_is_ring_full(mhi_cntrl, tre_ring); > > > - if (unlikely(ret)) { > > > - ret = -EAGAIN; > > > - goto exit_unlock; > > > - } > > > + if (unlikely(ret)) > > > + return -EAGAIN; > > > ret = mhi_gen_tre(mhi_cntrl, mhi_chan, buf_info, mflags); > > > if (unlikely(ret)) > > > - goto exit_unlock; > > > + return ret; > > > + > > > + read_lock_irqsave(&mhi_cntrl->pm_lock, flags); > > > /* Packet is queued, take a usage ref to exit M3 if necessary > > > * for host->device buffer, balanced put is done on buffer completion > > > @@ -1158,7 +1156,6 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info, > > > if (dir == DMA_FROM_DEVICE) > > > mhi_cntrl->runtime_put(mhi_cntrl); > > > -exit_unlock: > > > read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags); > > > return ret; > > > -- > > > 2.7.4 > > > > > > > -- மணிவண்ணன் சதாசிவம்