Commit b6645112 authored by Jaegeuk Kim's avatar Jaegeuk Kim Committed by Martin K. Petersen
Browse files

scsi: ufs: Atomic update for clkgating_enable 

While running a stress test which enables/disables clkgating, we
occasionally hit device timeout. This patch avoids a subtle race condition
to address it.

Link: https://lore.kernel.org/r/20201117165839.1643377-3-jaegeuk@kernel.org


Reviewed-by: default avatarCan Guo <cang@codeaurora.org>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@google.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent fd62de11

drivers/scsi/ufs/ufshcd.c

+6 −6
Original line number Diff line number Diff line
@@ -1818,19 +1818,19 @@ 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)

		__ufshcd_release(hba);

	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;

}