[PATCH v7 2/9] iio: ssp_sensors: factor out pending list add/remove helper(s)

[Sanjay Chitroda <sanjayembeddedse@gmail.com>]

From: Sanjay Chitroda <sanjayembeddedse@gmail.com>

The SSP SPI transfer path manipulates the pending message list in
multiple places, each time open-coding the same locking and list
operations.

Re-factor the pending list add and delete logic into small helper
functions and drop use_no_irq variable to avoid duplication and
simplify transfer flow to follow.

No functional change intended.

Signed-off-by: Sanjay Chitroda <sanjayembeddedse@gmail.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
---
Changes in v7:
- Following suggestion from Andy, keep helper API definition in single
  line and re-place the comment section
- v6 change: https://lore.kernel.org/all/20260415050749.3858046-4-sanjayembedded@gmail.com/
Changes in v6:
- Include tag for the suggestion of helper functions
- Drop completely use_no_irq variable with review comment from Andy
- v5 change: https://lore.kernel.org/all/20260406080852.2727453-4-sanjayembedded@gmail.com/
---
 drivers/iio/common/ssp_sensors/ssp_spi.c | 58 ++++++++++++++----------
 1 file changed, 33 insertions(+), 25 deletions(-)

diff --git a/drivers/iio/common/ssp_sensors/ssp_spi.c b/drivers/iio/common/ssp_sensors/ssp_spi.c
index 08ed92859be0..870214551f0b 100644
--- a/drivers/iio/common/ssp_sensors/ssp_spi.c
+++ b/drivers/iio/common/ssp_sensors/ssp_spi.c
@@ -174,15 +174,35 @@ static int ssp_check_lines(struct ssp_data *data, bool state)
 	return 0;
 }
 
+static inline void ssp_pending_add(struct ssp_data *data, struct ssp_msg *msg)
+{
+	/*
+	 * Check if this is a short one way message or the whole transfer has
+	 * second part after an interrupt.
+	 */
+	if (msg->length == 0)
+		return;
+
+	mutex_lock(&data->pending_lock);
+	list_add_tail(&msg->list, &data->pending_list);
+	mutex_unlock(&data->pending_lock);
+}
+
+static inline void ssp_pending_del(struct ssp_data *data, struct ssp_msg *msg)
+{
+	/* See ssp_pending_add() for transfer length logic */
+	if (msg->length == 0)
+		return;
+
+	mutex_lock(&data->pending_lock);
+	list_del(&msg->list);
+	mutex_unlock(&data->pending_lock);
+}
+
 static int ssp_do_transfer(struct ssp_data *data, struct ssp_msg *msg,
 			   struct completion *done, int timeout)
 {
 	int status;
-	/*
-	 * check if this is a short one way message or the whole transfer has
-	 * second part after an interrupt
-	 */
-	const bool use_no_irq = msg->length == 0;
 
 	if (data->shut_down)
 		return -EPERM;
@@ -202,35 +222,23 @@ static int ssp_do_transfer(struct ssp_data *data, struct ssp_msg *msg,
 		goto _error_locked;
 	}
 
-	if (!use_no_irq) {
-		mutex_lock(&data->pending_lock);
-		list_add_tail(&msg->list, &data->pending_list);
-		mutex_unlock(&data->pending_lock);
-	}
+	ssp_pending_add(data, msg);
 
 	status = ssp_check_lines(data, true);
 	if (status < 0) {
-		if (!use_no_irq) {
-			mutex_lock(&data->pending_lock);
-			list_del(&msg->list);
-			mutex_unlock(&data->pending_lock);
-		}
+		ssp_pending_del(data, msg);
 		goto _error_locked;
 	}
 
 	mutex_unlock(&data->comm_lock);
 
-	if (!use_no_irq && done)
-		if (wait_for_completion_timeout(done,
-						msecs_to_jiffies(timeout)) ==
-		    0) {
-			mutex_lock(&data->pending_lock);
-			list_del(&msg->list);
-			mutex_unlock(&data->pending_lock);
+	if (msg->length && done &&
+	    !wait_for_completion_timeout(done, msecs_to_jiffies(timeout))) {
+		ssp_pending_del(data, msg);
 
-			data->timeout_cnt++;
-			return -ETIMEDOUT;
-		}
+		data->timeout_cnt++;
+		return -ETIMEDOUT;
+	}
 
 	return 0;
 
-- 
2.34.1