RE: [PATCH v1] scsi: ufs: remove clk_scaling_lock when clkscaling isn't supported.

Kiwoong Kim
2022-02-15T06:03:39Z

> > - down_read(&hba->clk_scaling_lock);
> > + if (ufshcd_is_clkscaling_supported(hba))
> > + down_read(&hba->clk_scaling_lock);
> >
> > lrbp = &hba->lrb[tag];
> > WARN_ON(lrbp->cmd);
>
> I don't like this patch at all. This patch makes testing the UFS driver
> more complicated without having any clear benefit. Additionally, adding
> if-statements in front of locking makes static source code analysis harder
> and is an anti-pattern. Please don't do this.
>
> Bart.

The benefit that I think is not blocking dev cmd during submitting a scsi cmd.
Rather, I don't understand why this lock is required if a SoC doesn't support clk scaling.

The period of ringing doorbells has been already protected by spin lock.

Thanks.
Kiwoong Kim