From: Can Guo cang@codeaurora.org
[ Upstream commit 73cc291c270248567245f084dcdf5078069af6b5 ]
If someone plays with the UFS clk scaling devfreq governor through sysfs, ufshcd_devfreq_scale may be called even when HBA is not runtime ACTIVE. This can lead to unexpected error. We cannot just protect it by calling pm_runtime_get_sync() because that may cause a race condition since HBA runtime suspend ops need to suspend clk scaling. To fix this call pm_runtime_get_noresume() and check HBA's runtime status. Only proceed if HBA is runtime ACTIVE, otherwise just bail.
governor_store devfreq_performance_handler update_devfreq devfreq_set_target ufshcd_devfreq_target ufshcd_devfreq_scale
Link: https://lore.kernel.org/r/1600758548-28576-1-git-send-email-cang@codeaurora.... Reviewed-by: Stanley Chu stanley.chu@mediatek.com Signed-off-by: Can Guo cang@codeaurora.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/ufs/ufshcd.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index a3a3ee6e2a002..342e086e41991 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -1215,8 +1215,15 @@ static int ufshcd_devfreq_target(struct device *dev, } spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
+ pm_runtime_get_noresume(hba->dev); + if (!pm_runtime_active(hba->dev)) { + pm_runtime_put_noidle(hba->dev); + ret = -EAGAIN; + goto out; + } start = ktime_get(); ret = ufshcd_devfreq_scale(hba, scale_up); + pm_runtime_put(hba->dev);
trace_ufshcd_profile_clk_scaling(dev_name(hba->dev), (scale_up ? "up" : "down"),