On 2021-06-23 22:30, Adrian Hunter wrote:
On 23/06/21 10:35 am, Can Guo wrote:
To protect system suspend/resume from being disturbed by error
handling,
instead of using host_sem, let error handler call lock_system_sleep()
and
unlock_system_sleep() which achieve the same purpose. Remove the
host_sem
used in suspend/resume paths to make the code more readable.
Suggested-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 3695dd2..a09e4a2 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5907,6 +5907,11 @@ static void ufshcd_clk_scaling_suspend(struct
ufs_hba *hba, bool suspend)
static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
{
+ /*
+ * It is not safe to perform error handling while suspend or resume
is
+ * in progress. Hence the lock_system_sleep() call.
+ */
+ lock_system_sleep();
It looks to me like the system takes this lock quite early, even before
freezing tasks, so if anything needs the error handler to run it will
deadlock.
Hi Adrian,
UFS/hba system suspend/resume does not invoke or call error handling in
a
synchronous way. So, whatever UFS errors (which schedules the error
handler)
happens during suspend/resume, error handler will just wait here till
system
suspend/resume release the lock. Hence no worries of deadlock here.
Thanks,
Can Guo.
ufshcd_rpm_get_sync(hba);
if (pm_runtime_status_suspended(&hba->sdev_ufs_device->sdev_gendev)
||
hba->is_wlu_sys_suspended) {
@@ -5951,6 +5956,7 @@ static void ufshcd_err_handling_unprepare(struct
ufs_hba *hba)
ufshcd_clk_scaling_suspend(hba, false);
ufshcd_clear_ua_wluns(hba);
ufshcd_rpm_put(hba);
+ unlock_system_sleep();
}
static inline bool ufshcd_err_handling_should_stop(struct ufs_hba
*hba)
@@ -9053,16 +9059,13 @@ static int ufshcd_wl_suspend(struct device
*dev)
ktime_t start = ktime_get();
hba = shost_priv(sdev->host);
- down(&hba->host_sem);
if (pm_runtime_suspended(dev))
goto out;
ret = __ufshcd_wl_suspend(hba, UFS_SYSTEM_PM);
- if (ret) {
+ if (ret)
dev_err(&sdev->sdev_gendev, "%s failed: %d\n", __func__, ret);
- up(&hba->host_sem);
- }
out:
if (!ret)
@@ -9095,7 +9098,6 @@ static int ufshcd_wl_resume(struct device *dev)
hba->curr_dev_pwr_mode, hba->uic_link_state);
if (!ret)
hba->is_wlu_sys_suspended = false;
- up(&hba->host_sem);
return ret;
}
#endif
