Messages in this thread | | | Date | Tue, 27 Oct 2020 11:37:52 +0800 | From | Can Guo <> | Subject | Re: [PATCH v4 1/5] scsi: ufs: atomic update for clkgating_enable |
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On 2020-10-27 11:33, Jaegeuk Kim wrote: > On 10/27, Can Guo wrote: >> On 2020-10-27 03:51, Jaegeuk Kim wrote: >> > From: Jaegeuk Kim <jaegeuk@google.com> >> > >> > When giving a stress test which enables/disables clkgating, we hit >> > device >> > timeout sometimes. This patch avoids subtle racy condition to address >> > it. >> > >> > Note that, this requires a patch to address the device stuck by >> > REQ_CLKS_OFF in >> > __ufshcd_release(). >> > >> > The fix is "scsi: ufs: avoid to call REQ_CLKS_OFF to CLKS_OFF". >> >> Why don't you just squash the fix into this one? > > I'm seeing this patch just revealed that problem.
That scenario (back to back calling of ufshcd_release()) only happens when you stress the clkgate_enable sysfs node, so let's keep the fix as one to make things simple. What do you think?
Thanks,
Can Guo.
> >> >> Thanks, >> >> Can Guo. >> >> > >> > Signed-off-by: Jaegeuk Kim <jaegeuk@google.com> >> > --- >> > drivers/scsi/ufs/ufshcd.c | 12 ++++++------ >> > 1 file changed, 6 insertions(+), 6 deletions(-) >> > >> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >> > index cc8d5f0c3fdc..6c9269bffcbd 100644 >> > --- a/drivers/scsi/ufs/ufshcd.c >> > +++ b/drivers/scsi/ufs/ufshcd.c >> > @@ -1808,19 +1808,19 @@ static ssize_t >> > ufshcd_clkgate_enable_store(struct device *dev, >> > return -EINVAL; >> > >> > value = !!value; >> > + >> > + spin_lock_irqsave(hba->host->host_lock, flags); >> > if (value == hba->clk_gating.is_enabled) >> > goto out; >> > >> > - if (value) { >> > - ufshcd_release(hba); >> > - } else { >> > - spin_lock_irqsave(hba->host->host_lock, flags); >> > + if (value) >> > + __ufshcd_release(hba); >> > + else >> > hba->clk_gating.active_reqs++; >> > - spin_unlock_irqrestore(hba->host->host_lock, flags); >> > - } >> > >> > hba->clk_gating.is_enabled = value; >> > out: >> > + spin_unlock_irqrestore(hba->host->host_lock, flags); >> > return count; >> > }
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