[PATCH v2 13/19] platform/x86/intel/tpmi: Use guard() for tpmi_dev_lock in the status read

[Kuppuswamy Sathyanarayanan]

tpmi_read_feature_status() takes tpmi_dev_lock explicitly and unwinds
through an err_unlock label, which is what forced the two error paths
before the mailbox command is issued to be gotos rather than returns.

Take the mutex with guard() and return directly from those two paths.

The done_proc label stays, because the paths that reach it have already
handed the mailbox to the hardware and still owe it the CPL write before
dropping the lock. That is unchanged: the two early failures never wrote
CPL before either.

No functional change intended.

Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
 drivers/platform/x86/intel/tpmi_common.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/intel/tpmi_common.c b/drivers/platform/x86/intel/tpmi_common.c
index 7f6cd0fb23d7..00f27ac0a753 100644
--- a/drivers/platform/x86/intel/tpmi_common.c
+++ b/drivers/platform/x86/intel/tpmi_common.c
@@ -272,12 +272,12 @@ static int tpmi_read_feature_status(struct intel_tpmi_info *tpmi_info, int featu
 	if (!tpmi_info->tpmi_control_mem)
 		return -EFAULT;
 
-	mutex_lock(&tpmi_dev_lock);
+	guard(mutex)(&tpmi_dev_lock);
 
 	/* Wait for owner bit set to 0 (none) */
 	ret = tpmi_wait_for_owner(tpmi_info, TPMI_OWNER_NONE);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	/* set command id to 0x10 for TPMI_GET_STATE */
 	data = FIELD_PREP(TMPI_CONTROL_DATA_CMD, TPMI_CONTROL_GET_STATE_CMD);
@@ -291,7 +291,7 @@ static int tpmi_read_feature_status(struct intel_tpmi_info *tpmi_info, int featu
 	/* Wait for owner bit set to in-band */
 	ret = tpmi_wait_for_owner(tpmi_info, TPMI_OWNER_IN_BAND);
 	if (ret)
-		goto err_unlock;
+		return ret;
 
 	/* Set Run Busy and packet length of 2 dwords */
 	control = TPMI_CONTROL_STATUS_RB;
@@ -323,9 +323,6 @@ static int tpmi_read_feature_status(struct intel_tpmi_info *tpmi_info, int featu
 	/* Set CPL "completion" bit */
 	writeq(TPMI_CONTROL_STATUS_CPL, tpmi_info->tpmi_control_mem + TPMI_CONTROL_STATUS_OFFSET);
 
-err_unlock:
-	mutex_unlock(&tpmi_dev_lock);
-
 	return ret;
 }
 
-- 
2.43.0