From: Bart Van Assche <bvanassche@acm.org>
To: "Peter Wang (王信友)" <peter.wang@mediatek.com>,
"quic_rampraka@quicinc.com" <quic_rampraka@quicinc.com>,
"quic_nguyenb@quicinc.com" <quic_nguyenb@quicinc.com>,
"quic_ziqichen@quicinc.com" <quic_ziqichen@quicinc.com>,
"quic_nitirawa@quicinc.com" <quic_nitirawa@quicinc.com>,
"beanhuo@micron.com" <beanhuo@micron.com>,
"avri.altman@wdc.com" <avri.altman@wdc.com>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"junwoo80.lee@samsung.com" <junwoo80.lee@samsung.com>,
"mani@kernel.org" <mani@kernel.org>,
"quic_cang@quicinc.com" <quic_cang@quicinc.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"alim.akhtar@samsung.com" <alim.akhtar@samsung.com>,
"jejb@linux.ibm.com" <jejb@linux.ibm.com>,
"quic_asutoshd@quicinc.com" <quic_asutoshd@quicinc.com>,
"quic_mnaresh@quicinc.com" <quic_mnaresh@quicinc.com>,
"manivannan.sadhasivam@linaro.org"
<manivannan.sadhasivam@linaro.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] scsi: ufs: core: quiesce request queues before check pending cmds
Date: Tue, 25 Jun 2024 09:13:23 -0700 [thread overview]
Message-ID: <3c7e776e-df2e-4718-995f-5e5dfa3cc916@acm.org> (raw)
In-Reply-To: <ee45ce9429b1f69147c1a01e07b050275b4009bf.camel@mediatek.com>
On 6/24/24 8:38 PM, Peter Wang (王信友) wrote:
> But ufshcd_scsi_block_requests usage is correct in SDR mode.
ufshcd_scsi_block_requests() uses scsi_block_requests(). It is almost
never correct to use scsi_block_requests() in a blk-mq driver because
scsi_block_requests() does not wait for ongoing request submission
calls to complete. scsi_block_requests() is a legacy from the time when
all request dispatching and queueing was protected by the SCSI host
lock, a change that was made in 2010 or about 14 years ago. See also
https://lore.kernel.org/linux-scsi/20101105002409.GA21714@havoc.gtf.org/
> So, I think ufshcd_wait_for_doorbell_clr should be revise.
> Check tr_doorbell in SDR mode. (before 8d077ede48c1 do)
> Check each HWQ's are all empty in MCQ mode. (need think how to do)
> Make sure all requests is complete, and finish this function' job
> correctly.
> Or there still have a gap in ufshcd_wait_for_doorbell_clr.
ufshcd_wait_for_doorbell_clr() should be removed and
ufshcd_clock_scaling_prepare() should use blk_mq_freeze_*().
See also my patch "ufs: Simplify the clock scaling mechanism
implementation" from 5 years ago
(https://lore.kernel.org/linux-scsi/20191112173743.141503-5-bvanassche@acm.org/).
Best regards,
Bart.
next prev parent reply other threads:[~2024-06-25 16:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-07 10:06 Ziqi Chen
2024-06-07 12:33 ` Bart Van Assche
2024-06-11 11:02 ` Ziqi Chen
2024-06-11 13:51 ` Bart Van Assche
2024-06-12 6:07 ` Ziqi Chen
2024-06-11 13:54 ` Bart Van Assche
2024-06-20 20:57 ` Bart Van Assche
2024-06-24 9:56 ` Ziqi Chen
2024-06-24 16:29 ` Bart Van Assche
2024-06-25 3:38 ` Peter Wang (王信友)
2024-06-25 16:13 ` Bart Van Assche [this message]
2024-06-26 3:52 ` Peter Wang (王信友)
2024-06-26 13:18 ` Ziqi Chen
2024-06-26 16:33 ` Bart Van Assche
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