| Message ID | 20201119062916.12931-1-stanley.chu@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v1] scsi: ufs: Fix race between shutdown and runtime resume flow | expand |
On 2020-11-19 14:29, Stanley Chu wrote: > If UFS host device is in runtime-suspended state while > UFS shutdown callback is invoked, UFS device shall be > resumed for register accesses. Currently only UFS local > runtime resume function will be invoked to wake up the host. > This is not enough because if someone triggers runtime > resume from block layer, then race may happen between > shutdown and runtime resume flow, and finally lead to > unlocked register access. > > To fix this kind of issues, in ufshcd_shutdown(), use > pm_runtime_get_sync() instead of resuming UFS device by > ufshcd_runtime_resume() "internally" to let runtime PM > framework manage the whole resume flow. > > Fixes: 57d104c153d3 ("ufs: add UFS power management support") > Signed-off-by: Stanley Chu <stanley.chu@mediatek.com> Reviewed-by: Can Guo <cang@codeaurora.org> > --- > drivers/scsi/ufs/ufshcd.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > index 80cbce414678..bb16cc04f106 100644 > --- a/drivers/scsi/ufs/ufshcd.c > +++ b/drivers/scsi/ufs/ufshcd.c > @@ -8941,11 +8941,7 @@ int ufshcd_shutdown(struct ufs_hba *hba) > if (ufshcd_is_ufs_dev_poweroff(hba) && ufshcd_is_link_off(hba)) > goto out; > > - if (pm_runtime_suspended(hba->dev)) { > - ret = ufshcd_runtime_resume(hba); > - if (ret) > - goto out; > - } > + pm_runtime_get_sync(hba->dev); > > ret = ufshcd_suspend(hba, UFS_SHUTDOWN_PM); > out:
On Thu, 19 Nov 2020 14:29:16 +0800, Stanley Chu wrote: > If UFS host device is in runtime-suspended state while > UFS shutdown callback is invoked, UFS device shall be > resumed for register accesses. Currently only UFS local > runtime resume function will be invoked to wake up the host. > This is not enough because if someone triggers runtime > resume from block layer, then race may happen between > shutdown and runtime resume flow, and finally lead to > unlocked register access. > > [...] Applied to 5.10/scsi-fixes, thanks! [1/1] scsi: ufs: Fix race between shutdown and runtime resume flow https://git.kernel.org/mkp/scsi/c/e92643db5148
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 80cbce414678..bb16cc04f106 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -8941,11 +8941,7 @@ int ufshcd_shutdown(struct ufs_hba *hba) if (ufshcd_is_ufs_dev_poweroff(hba) && ufshcd_is_link_off(hba)) goto out; - if (pm_runtime_suspended(hba->dev)) { - ret = ufshcd_runtime_resume(hba); - if (ret) - goto out; - } + pm_runtime_get_sync(hba->dev); ret = ufshcd_suspend(hba, UFS_SHUTDOWN_PM); out:
If UFS host device is in runtime-suspended state while UFS shutdown callback is invoked, UFS device shall be resumed for register accesses. Currently only UFS local runtime resume function will be invoked to wake up the host. This is not enough because if someone triggers runtime resume from block layer, then race may happen between shutdown and runtime resume flow, and finally lead to unlocked register access. To fix this kind of issues, in ufshcd_shutdown(), use pm_runtime_get_sync() instead of resuming UFS device by ufshcd_runtime_resume() "internally" to let runtime PM framework manage the whole resume flow. Fixes: 57d104c153d3 ("ufs: add UFS power management support") Signed-off-by: Stanley Chu <stanley.chu@mediatek.com> --- drivers/scsi/ufs/ufshcd.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)