linux-kernel - Re: [PATCH rdma-rc 1/3] RDMA/hns: Fix the Oops during rmmod or insmod ko when reset occurs

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Date:   Fri, 11 Jan 2019 14:34:11 -0700
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     "Wei Hu (Xavier)" <xavier.huwei@...wei.com>
Cc:     dledford@...hat.com, linux-rdma@...r.kernel.org,
        lijun_nudt@....com, oulijun@...wei.com, liudongdong3@...wei.com,
        liuyixian@...wei.com, zhangxiping3@...wei.com, linuxarm@...wei.com,
        linux-kernel@...r.kernel.org, xavier_huwei@....com
Subject: Re: [PATCH rdma-rc 1/3] RDMA/hns: Fix the Oops during rmmod or
 insmod ko when reset occurs

On Thu, Jan 10, 2019 at 09:57:41PM +0800, Wei Hu (Xavier) wrote:
> +	/* Check the status of the current software reset process, if in
> +	 * software reset process, wait until software reset process finished,
> +	 * in order to ensure that reset process and this function will not call
> +	 * __hns_roce_hw_v2_uninit_instance at the same time.
> +	 * If a timeout occurs, it indicates that the network subsystem has
> +	 * encountered a serious error and cannot be recovered from the reset
> +	 * processing.
> +	 */
> +	if (ops->ae_dev_resetting(handle)) {
> +		dev_warn(dev, "Device is busy in resetting state. waiting.\n");
> +		end = msecs_to_jiffies(HNS_ROCE_V2_RST_PRC_MAX_TIME) + jiffies;
> +		while (ops->ae_dev_resetting(handle) &&
> +		       time_before(jiffies, end))
> +			msleep(20);

Really? Does this have to be so ugly? Why isn't there just a simple
lock someplace that is held during reset?

I'm skeptical that all this strange looking stuff is properly locked
and concurrency safe.

Also, this series seems a bit big for -rc

Jason