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Subject: Re: [PATCH v1 1/2] scsi: ufs: Fix unbalanced scsi_block_reqs_cnt
 caused by ufshcd_hold()
To:     Can Guo <cang@codeaurora.org>, nguyenb@codeaurora.org,
        hongwus@codeaurora.org, rnayak@codeaurora.org,
        linux-scsi@vger.kernel.org, kernel-team@android.com,
        saravanak@google.com, salyzyn@google.com
Cc:     Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Bart Van Assche <bvanassche@acm.org>,
        open list <linux-kernel@vger.kernel.org>
References: <1604384682-15837-1-git-send-email-cang@codeaurora.org>
 <1604384682-15837-2-git-send-email-cang@codeaurora.org>
From:   "Asutosh Das (asd)" <asutoshd@codeaurora.org>
Message-ID: <ddefc6a0-6a70-692b-b9bc-d3a290273f72@codeaurora.org>
Date:   Wed, 11 Nov 2020 09:33:44 -0800
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On 11/2/2020 10:24 PM, Can Guo wrote:
> The scsi_block_reqs_cnt increased in ufshcd_hold() is supposed to be
> decreased back in ufshcd_ungate_work() in a paired way. However, if
> specific ufshcd_hold/release sequences are met, it is possible that
> scsi_block_reqs_cnt is increased twice but only one ungate work is
> queued. To make sure scsi_block_reqs_cnt is handled by ufshcd_hold() and
> ufshcd_ungate_work() in a paired way, increase it only if queue_work()
> returns true.
> 
> Signed-off-by: Can Guo <cang@codeaurora.org>
> Reviewed-by: Hongwu Su <hongwus@codeaurora.org>
> ---

Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>

>   drivers/scsi/ufs/ufshcd.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 847f355..efa7d86 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1634,12 +1634,12 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
>   		 */
>   		/* fallthrough */
>   	case CLKS_OFF:
> -		ufshcd_scsi_block_requests(hba);
>   		hba->clk_gating.state = REQ_CLKS_ON;
>   		trace_ufshcd_clk_gating(dev_name(hba->dev),
>   					hba->clk_gating.state);
> -		queue_work(hba->clk_gating.clk_gating_workq,
> -			   &hba->clk_gating.ungate_work);
> +		if (queue_work(hba->clk_gating.clk_gating_workq,
> +			       &hba->clk_gating.ungate_work))
> +			ufshcd_scsi_block_requests(hba);
>   		/*
>   		 * fall through to check if we should wait for this
>   		 * work to be done or not.
> 


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