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Message-ID: <1ac2154c-e74c-ebec-90d1-11ddf9b3ba1a@quicinc.com>
Date:   Mon, 31 Jul 2023 11:07:50 +0530
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Subject: Re: [PATCH v4 9/9] bus: mhi: ep: wake up host if the MHI state is in
 M3
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To:     Manivannan Sadhasivam <mani@kernel.org>,
        Dan Carpenter <dan.carpenter@linaro.org>
CC:     <manivannan.sadhasivam@linaro.org>, <helgaas@kernel.org>,
        <linux-pci@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <quic_vbadigan@quicinc.com>,
        <quic_nitegupt@quicinc.com>, <quic_skananth@quicinc.com>,
        <quic_ramkri@quicinc.com>, <krzysztof.kozlowski@linaro.org>,
        Jeffrey Hugo <quic_jhugo@quicinc.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dan Carpenter <error27@gmail.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        "open list:MHI BUS" <mhi@lists.linux.dev>
References: <1689232218-28265-1-git-send-email-quic_krichai@quicinc.com>
 <1689232218-28265-10-git-send-email-quic_krichai@quicinc.com>
 <20230728043452.GI4433@thinkpad>
 <15a19a2d-d6e8-4fbc-a31d-561cff00b01a@kadam.mountain>
 <20230728153555.GA9129@thinkpad>
From:   Krishna Chaitanya Chundru <quic_krichai@quicinc.com>
In-Reply-To: <20230728153555.GA9129@thinkpad>
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On 7/28/2023 9:05 PM, Manivannan Sadhasivam wrote:
> On Fri, Jul 28, 2023 at 08:50:55AM +0300, Dan Carpenter wrote:
>> On Fri, Jul 28, 2023 at 10:04:52AM +0530, Manivannan Sadhasivam wrote:
>>>> @@ -464,6 +484,13 @@ int mhi_ep_queue_skb(struct mhi_ep_device *mhi_dev, struct sk_buff *skb)
>>>>   	buf_left = skb->len;
>>>>   	ring = &mhi_cntrl->mhi_chan[mhi_chan->chan].ring;
>>>>   
>>>> +	if (mhi_cntrl->mhi_state == MHI_STATE_M3) {
>>>> +		if (mhi_ep_wake_host(mhi_cntrl)) {
>>> Don't you need lock here in the case of multiple queue requests?
>>>
>>> - Mani
>>>
>>>> +			dev_err(dev, "Failed to wakeup host\n");
>>>> +			return -ENODEV;
>>>> +		}
>>>> +	}
>>>> +
>>>>   	mutex_lock(&mhi_chan->lock);
>>          ^^^^^^^^^^^^^^^^^^^^^^^^^^
>> This lock isn't enough?
>>
> The position of this lock won't prevent cocurrent access to mhi_ep_wake_host().
>
> - Mani
I will add the lock in the next series.
>> regards,
>> dan carpenter