Hi Rafael
Would you please help to review this patch assoociated with PM resume
callback implementation?
Original code that ufshcd_system/runtime_resume returns '0' in case
resume failed due to the UFS device and UFS LINk are powered off(hba-
>is_powered == false).
In the patch 2/3 Add handling of the return value of
pm_runtime_get_sync() is to fix race exists between shudown path and
device access through sysfs node.
Thanks,
Bean
On Thu, 2020-12-24 at 18:20 +0100, Bean Huo wrote:
> From: Bean Huo <beanhuo@xxxxxxxxxx>
>
> After ufshcd_shutdown(), both UFS device and UFS LINk are powered
> off,
> return '0' will mislead the upper PM layer since the device has not
> been
> successfully resumed yet. This will let pm_runtime_get_sync() caller
> mistakenly believe the device/LINK has been resumed, which leads to
> request processing timeout that was en-queued later.
>
> To fix this, let ufshcd_system/runtimie_resume() return -EBUSY in
> case of
> hba->is_powered == false.
>
> Signed-off-by: Bean Huo <beanhuo@xxxxxxxxxx>
> ---
> drivers/scsi/ufs/ufshcd.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index e221add25a7e..e1bcac51c01f 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -8950,14 +8950,16 @@ int ufshcd_system_resume(struct ufs_hba *hba)
> return -EINVAL;
> }
>
> - if (!hba->is_powered || pm_runtime_suspended(hba->dev))
> + if (!hba->is_powered || pm_runtime_suspended(hba->dev)) {
> /*
> * Let the runtime resume take care of resuming
> * if runtime suspended.
> */
> + ret = -EBUSY;
> goto out;
> - else
> + } else {
> ret = ufshcd_resume(hba, UFS_SYSTEM_PM);
> + }
> out:
> trace_ufshcd_system_resume(dev_name(hba->dev), ret,
> ktime_to_us(ktime_sub(ktime_get(), start)),
> @@ -9026,10 +9028,12 @@ int ufshcd_runtime_resume(struct ufs_hba
> *hba)
> if (!hba)
> return -EINVAL;
>
> - if (!hba->is_powered)
> + if (!hba->is_powered) {
> + ret = -EBUSY;
> goto out;
> - else
> + } else {
> ret = ufshcd_resume(hba, UFS_RUNTIME_PM);
> + }
> out:
> trace_ufshcd_runtime_resume(dev_name(hba->dev), ret,
> ktime_to_us(ktime_sub(ktime_get(), start)),
