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Subject[PATCH 1/6] scsi: ufs: atomic update for clkgating_enable
Date
From: Jaegeuk Kim <jaegeuk@google.com>

When giving a stress test which enables/disables clkgating, we hit device
timeout sometimes. This patch avoids subtle racy condition to address it.

Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
---
drivers/scsi/ufs/ufshcd.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 1d157ff58d817..d929c3d1e58cc 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1791,19 +1791,19 @@ static ssize_t ufshcd_clkgate_enable_store(struct device *dev,
return -EINVAL;

value = !!value;
+
+ spin_lock_irqsave(hba->host->host_lock, flags);
if (value == hba->clk_gating.is_enabled)
goto out;

- if (value) {
- ufshcd_release(hba);
- } else {
- spin_lock_irqsave(hba->host->host_lock, flags);
+ if (value)
+ hba->clk_gating.active_reqs--;
+ else
hba->clk_gating.active_reqs++;
- spin_unlock_irqrestore(hba->host->host_lock, flags);
- }

hba->clk_gating.is_enabled = value;
out:
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
return count;
}

--
2.28.0.618.gf4bc123cb7-goog
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