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

Sanjay Chitroda
2026-04-26T09:17:27Z

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