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From: "hoyoung seo" <hy50.seo@samsung.com>
To: "'Bart Van Assche'" <bvanassche@acm.org>, <linux-scsi@vger.kernel.org>,
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Subject: RE: [PATCH v1] scsi: ufs: core: Remove the ufshcd_release in
 ufshcd_err_handling_prepare
Date: Wed, 31 Jan 2024 17:23:12 +0900
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> -----Original Message-----
> From: Bart Van Assche <bvanassche=40acm.org>
> Sent: Thursday, January 25, 2024 1:17 AM
> To: hoyoung seo <hy50.seo=40samsung.com>; linux-scsi=40vger.kernel.org; l=
inux-
> kernel=40vger.kernel.org; alim.akhtar=40samsung.com; avri.altman=40wdc.co=
m;
> jejb=40linux.ibm.com; martin.petersen=40oracle.com; beanhuo=40micron.com;
> kwangwon.min=40samsung.com; kwmad.kim=40samsung.com; sh425.lee=40samsung.=
com;
> sc.suh=40samsung.com; quic_nguyenb=40quicinc.com; cpgs=40samsung.com;
> grant.jung=40samsung.com; junwoo80.lee=40samsung.com
> Subject: Re: =5BPATCH v1=5D scsi: ufs: core: Remove the ufshcd_release in
> ufshcd_err_handling_prepare
>=20
> On 1/22/24 18:38, hoyoung seo wrote:
> > When err_handler is completed, active_reqs becomes negative because
> > ufshcd_release() is called again in ufshcd_err_handling_unprepare().
> > I tested it while printing the log, and if I misanalyzed it, let me kno=
w.
>=20
> Please repeat your analysis. I think this patch is wrong.
>=20
> Thanks,
>=20
> Bart.

Hi,

I do not understand. why you said my patch is wrong.
If ufs entered suspend with hibern8 state then the hba->clk_gating.active_r=
eqs is 1.
After that run wl_resume(), ufs drvier send hibern8 exit command.
At that time, if the command timeout or error occurs, the err_handler is ac=
tivated.=20
Then the active_reqs pair may not fit.

So to sum up, ufs_release() is performed 3 time.
(wl_resume(), ufshcd_err_handling_prepare(), ufshcd_err_handling_unprepare(=
))
And the ufshcd_hold() is performed 2 time(__ufshcd_wl_suspend(), ufshcd_err=
_handling_prepare())
So the paire of active_reqs is not correct.
So I deleted the ufshcd_release() in ufshcd_err_handling_prepare().

The ufshcd_release() was not called again even in the pm_op_in_progress sta=
te in 4.xx version of the kernel.
But now if is_sys_suspended is 1, then ufshcd_release() is called once more=
.
I don't understand why this is added and the pair doesn't fit.

Please check it again.
Thanks.

Seo.