On 2/4/22 23:39, Kiwoong Kim wrote:
clk_scaling_lock is to prevent from running clkscaling related operations
with others which might be affected by the operations concurrently.
I think it looks hardware specific.
If the feature isn't supported, I think there is no reasonto prevent from
running other functions, such as ufshcd_queuecommand and
ufshcd_exec_dev_cmd, concurrently.
So I add a condition at some points protecting with clk_scaling_lock.
Signed-off-by: Kiwoong Kim <kwmad.kim@xxxxxxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 460d2b4..8471c90 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2980,7 +2980,8 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba,
/* Protects use of hba->reserved_slot. */
lockdep_assert_held(&hba->dev_cmd.lock);
- down_read(&hba->clk_scaling_lock);
+ if (ufshcd_is_clkscaling_supported(hba))
+ down_read(&hba->clk_scaling_lock);
lrbp = &hba->lrb[tag];
WARN_ON(lrbp->cmd);
I don't like this patch at all. This patch makes testing the UFS driver
more complicated without having any clear benefit. Additionally, adding
if-statements in front of locking makes static source code analysis
harder and is an anti-pattern. Please don't do this.
Bart.
