On 7/30/22 00:08, Stanley Chu wrote:
Hi Bart,
On Sat, Jul 30, 2022 at 4:12 AM Bart Van Assche <bvanassche@xxxxxxx> wrote:
On 7/29/22 00:55, Stanley Chu wrote:
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 581d88af07ab..dc57a7988023 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1574,8 +1574,6 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
ufshcd_rpm_get_sync(hba);
ufshcd_hold(hba, false);
- hba->clk_scaling.is_enabled = value;
-
if (value) {
ufshcd_resume_clkscaling(hba);
} else {
@@ -1586,6 +1584,8 @@ static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
__func__, err);
}
+ hba->clk_scaling.is_enabled = value;
+
ufshcd_release(hba);
ufshcd_rpm_put_sync(hba);
out:
@@ -7259,7 +7259,8 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
hba->silence_err_logs = false;
/* scale up clocks to max frequency before full reinitialization */
- ufshcd_scale_clks(hba, true);
+ if (ufshcd_is_clkscaling_supported(hba) && hba->clk_scaling.is_enabled)
+ ufshcd_scale_clks(hba, true);
err = ufshcd_hba_enable(hba);
I see a race condition between the hba->clk_scaling.is_enabled check in
ufshcd_host_reset_and_restore() and the code that sets
ufshcd_clkscale_enable_store(). Shouldn't the code in
ufshcd_host_reset_and_restore() that scales up the clocks be serialized
against ufshcd_clkscale_enable_store()?
Both check and set paths are serialized by hba->host_sem currently.
Would I miss any other unserialized paths?
Where in ufshcd_host_reset_and_restore() or in its callers is
hba->host_sem obtained? I don't see it. Am I perhaps overlooking something?
Thanks,
Bart.
