linux-kernel - RE: [PATCH v2 1/2] scsi: ufs: core: Introduce a new clock

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Message-ID:
 <BL0PR04MB6564D3BBB11D00067485F5CBFC4B2@BL0PR04MB6564.namprd04.prod.outlook.com>
Date: Tue, 29 Oct 2024 18:39:08 +0000
From: Avri Altman <Avri.Altman@....com>
To: Bart Van Assche <bvanassche@....org>, "Martin K . Petersen"
	<martin.petersen@...cle.com>
CC: "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2 1/2] scsi: ufs: core: Introduce a new clock_gating lock

> On 10/29/24 3:29 AM, Avri Altman wrote:
> > +     scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) {
> > +             /*
> > +              * In case you are here to cancel this work the gating state
> > +              * would be marked as REQ_CLKS_ON. In this case save time by
> > +              * skipping the gating work and exit after changing the clock
> > +              * state to CLKS_ON.
> > +              */
> > +             if (hba->clk_gating.is_suspended || (hba->clk_gating.state !=
> REQ_CLKS_OFF)) {
> > +                     hba->clk_gating.state = CLKS_ON;
> > +                     trace_ufshcd_clk_gating(dev_name(hba->dev), hba-
> >clk_gating.state);
> > +                     return;
> > +             }
> > +             if (ufshcd_is_ufs_dev_busy(hba) || hba->ufshcd_state !=
> UFSHCD_STATE_OPERATIONAL)
> > +                     return;
> >       }
> 
> Please remove the superfluous parentheses from around the REQ_CLKS_OFF
> test 
OK.
But this is a format change while making functional change.

> and do not exceed the 80 column limit. git clang-format HEAD^ can help
> with restricting code to the 80 column limit.
Isn't the 80 characters restriction was changed long ago to 100 characters?
I always use strict checkpatch and doesn't get any warning about this.

> 
> > @@ -2072,18 +2055,18 @@ static ssize_t
> > ufshcd_clkgate_enable_store(struct device *dev,
> >
> >       value = !!value;
> >
> > -     spin_lock_irqsave(hba->host->host_lock, flags);
> > -     if (value == hba->clk_gating.is_enabled)
> > -             goto out;
> > +     scoped_guard(spinlock_irqsave, &hba->clk_gating.lock) {
> > +             if (value == hba->clk_gating.is_enabled)
> > +                     goto out;
> >
> > -     if (value)
> > -             __ufshcd_release(hba);
> > -     else
> > -             hba->clk_gating.active_reqs++;
> > +             if (value)
> > +                     __ufshcd_release(hba);
> > +             else
> > +                     hba->clk_gating.active_reqs++;
> >
> > -     hba->clk_gating.is_enabled = value;
> > +             hba->clk_gating.is_enabled = value;
> > +     }
> >   out:
> > -     spin_unlock_irqrestore(hba->host->host_lock, flags);
> >       return count;
> >   }
> 
> Please use guard() instead of scoped_guard() and remove the "out:"
> label.
Done.

> 
> > @@ -9173,11 +9157,10 @@ static int ufshcd_setup_clocks(struct ufs_hba
> *hba, bool on)
> >                               clk_disable_unprepare(clki->clk);
> >               }
> >       } else if (!ret && on) {
> > -             spin_lock_irqsave(hba->host->host_lock, flags);
> > -             hba->clk_gating.state = CLKS_ON;
> > +             scoped_guard(spinlock_irqsave, &hba->clk_gating.lock)
> > +                     hba->clk_gating.state = CLKS_ON;
> >               trace_ufshcd_clk_gating(dev_name(hba->dev),
> >                                       hba->clk_gating.state);
> > -             spin_unlock_irqrestore(hba->host->host_lock, flags);
> >       }
> 
> The above change moves the trace_ufshcd_clk_gating() call from inside the
> region protected by the host lock to outside the region protected by
> clk_gating.lock. If this is intentional, shouldn't this be mentioned in the patch
> description?
Yes. Intentional.
Done.

Thanks,
Avri

> 
> Thanks,
> 
> Bart.