Re: [PATCH v2 1/5] scsi: ufs: atomic update for clkgating_enable

Can Guo
2020-10-21T02:05:26Z

On 2020-10-21 03:52, 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.
>
> Cc: Alim Akhtar <alim.akhtar@samsung.com>
> Cc: Avri Altman <avri.altman@wdc.com>
> Cc: Can Guo <cang@codeaurora.org>
> Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>

Reviewed-by: Can Guo <cang@codeaurora.org>

Next time can you have a cover letter in case of multiple patches?

Thanks,

Can Guo.

> ---
> 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 b8f573a02713..7344353a9167 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -1807,19 +1807,19 @@ 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;
> }