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From: Bart Van Assche <bvanassche@acm.org>
To: Andrew Halaney <ahalaney@redhat.com>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Manivannan Sadhasivam <mani@kernel.org>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Hannes Reinecke <hare@suse.de>, Janek Kotas <jank@cadence.com>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	Avri Altman <avri.altman@wdc.com>,
	Can Guo <quic_cang@quicinc.com>
Cc: Will Deacon <will@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC v3 10/11] scsi: ufs: core: Perform read back to commit doorbell
Date: Thu, 21 Dec 2023 11:28:42 -0800	[thread overview]
Message-ID: <b8056aae-e7d5-4814-957d-585ab803a3aa@acm.org> (raw)
In-Reply-To: <20231221-ufs-reset-ensure-effect-before-delay-v3-10-2195a1b66d2e@redhat.com>

On 12/21/23 11:09, Andrew Halaney wrote:
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 75a03ee9a1ba..caebd589e08c 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -7050,7 +7050,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
>   
>   	ufshcd_writel(hba, 1 << task_tag, REG_UTP_TASK_REQ_DOOR_BELL);
>   	/* Make sure that doorbell is committed immediately */
> -	wmb();
> +	ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
>   
>   	spin_unlock_irqrestore(host->host_lock, flags);

There is a wait_for_completion_io_timeout() call later in this function and
it is safe to write to the REG_UTP_TASK_REQ_DOOR_BELL register from multiple
threads concurrently so I think the above wmb() call can be left out entirely.

Thanks,

Bart.

  reply	other threads:[~2023-12-21 19:28 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-21 19:09 [PATCH RFC v3 00/11] scsi: ufs: Remove overzealous memory barriers Andrew Halaney
2023-12-21 19:09 ` [PATCH RFC v3 01/11] scsi: ufs: qcom: Perform read back after writing reset bit Andrew Halaney
2023-12-22  8:18   ` Can Guo
2023-12-21 19:09 ` [PATCH RFC v3 02/11] scsi: ufs: qcom: Perform read back after writing REG_UFS_SYS1CLK_1US Andrew Halaney
2023-12-22  8:18   ` Can Guo
2023-12-21 19:09 ` [PATCH RFC v3 03/11] scsi: ufs: qcom: Perform read back after writing testbus config Andrew Halaney
2023-12-22  8:20   ` Can Guo
2023-12-21 19:09 ` [PATCH RFC v3 04/11] scsi: ufs: qcom: Perform read back after writing unipro mode Andrew Halaney
2023-12-22  8:23   ` Can Guo
2023-12-21 19:09 ` [PATCH RFC v3 05/11] scsi: ufs: qcom: Perform read back after writing CGC enable Andrew Halaney
2023-12-22  8:25   ` Can Guo
2023-12-21 19:09 ` [PATCH RFC v3 06/11] scsi: ufs: cdns-pltfrm: Perform read back after writing HCLKDIV Andrew Halaney
2023-12-21 19:09 ` [PATCH RFC v3 07/11] scsi: ufs: core: Perform read back after writing UTP_TASK_REQ_LIST_BASE_H Andrew Halaney
2023-12-21 19:30   ` Bart Van Assche
2023-12-22  8:26   ` Can Guo
2023-12-21 19:09 ` [PATCH RFC v3 08/11] scsi: ufs: core: Perform read back after disabling interrupts Andrew Halaney
2023-12-21 19:30   ` Bart Van Assche
2023-12-22  8:26   ` Can Guo
2023-12-21 19:09 ` [PATCH RFC v3 09/11] scsi: ufs: core: Perform read back after disabling UIC_COMMAND_COMPL Andrew Halaney
2023-12-21 19:29   ` Bart Van Assche
2023-12-22  8:26   ` Can Guo
2023-12-27  6:16   ` Manivannan Sadhasivam
2023-12-21 19:09 ` [PATCH RFC v3 10/11] scsi: ufs: core: Perform read back to commit doorbell Andrew Halaney
2023-12-21 19:28   ` Bart Van Assche [this message]
2023-12-22  8:27   ` Can Guo
2023-12-27  6:18   ` Manivannan Sadhasivam
2023-12-21 19:09 ` [PATCH RFC v3 11/11] scsi: ufs: core: Perform read back before writing run/stop regs Andrew Halaney
2023-12-21 19:25   ` Bart Van Assche
2023-12-22  8:27   ` Can Guo
2023-12-27  6:21   ` Manivannan Sadhasivam
2023-12-21 19:13 ` [PATCH RFC v3 00/11] scsi: ufs: Remove overzealous memory barriers Konrad Dybcio

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