From: Can Guo <cang@codeaurora.org>
To: asutoshd@codeaurora.org, nguyenb@codeaurora.org,
hongwus@codeaurora.org, rnayak@codeaurora.org,
linux-scsi@vger.kernel.org, kernel-team@android.com,
saravanak@google.com, salyzyn@google.com, cang@codeaurora.org
Cc: Alim Akhtar <alim.akhtar@samsung.com>,
Avri Altman <avri.altman@wdc.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Stanley Chu <stanley.chu@mediatek.com>,
Bean Huo <beanhuo@micron.com>,
Bart Van Assche <bvanassche@acm.org>,
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] scsi: ufs: Make sure clk scaling happens only when hba is runtime ACTIVE
Date: Tue, 22 Sep 2020 00:09:04 -0700 [thread overview]
Message-ID: <1600758548-28576-1-git-send-email-cang@codeaurora.org> (raw)
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,
which can lead to unexpected error. We cannot just protect it by calling
pm_runtime_get_sync, because that may cause racing problem since hba
runtime suspend ops needs to suspend clk scaling. In order to fix it, call
pm_runtime_get_noresume and check hba's runtime status, then 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
Signed-off-by: Can Guo <cang@codeaurora.org>
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e4cb994..847f355 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1294,8 +1294,15 @@ 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"),
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
next reply other threads:[~2020-09-22 7:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 7:09 Can Guo [this message]
2020-10-20 2:35 ` [PATCH] scsi: ufs: Make sure clk scaling happens only when hba is runtime ACTIVE Can Guo
2020-10-27 3:10 ` Stanley Chu
2020-11-19 15:03 ` Martin K. Petersen
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