Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.19 010/346] scsi: ufs: Make sure clk scaling happens only when HBA is runtime ACTIVE | Date | Mon, 28 Dec 2020 13:45:29 +0100 |
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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.org 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 7e4e6e982055e..61b1eae42ea85 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -1281,8 +1281,15 @@ 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"), -- 2.27.0
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