[PATCH v3 02/14] spi: Deduplicate IDR allocation code in spi_register_controller()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

Refactor spi_register_controller() to deduplicate IDR allocation
by introducing a new spi_controller_id_alloc() helper and using it.

For the dynamic ID allocation for the highest OF aliases, this will
shadow the ENOSPC error code as it's done for the other two cases.
It shouldn't be a problem as the result will be the same, we may
not get device ID allocated and flow will fail.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/spi/spi.c | 44 +++++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 21 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 8f3282a71c63..d8064998aa27 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3081,6 +3081,20 @@ static int spi_controller_check_ops(struct spi_controller *ctlr)
 	return 0;
 }
 
+/* Allocate dynamic bus number using Linux idr */
+static int spi_controller_id_alloc(struct spi_controller *ctlr, int start, int end)
+{
+	int id;
+
+	mutex_lock(&board_lock);
+	id = idr_alloc(&spi_master_idr, ctlr, start, end, GFP_KERNEL);
+	mutex_unlock(&board_lock);
+	if (WARN(id < 0, "couldn't get idr"))
+		return id == -ENOSPC ? -EBUSY : id;
+	ctlr->bus_num = id;
+	return 0;
+}
+
 /**
  * spi_register_controller - register SPI master or slave controller
  * @ctlr: initialized master, originally from spi_alloc_master() or
@@ -3124,24 +3138,16 @@ int spi_register_controller(struct spi_controller *ctlr)
 
 	if (ctlr->bus_num >= 0) {
 		/* Devices with a fixed bus num must check-in with the num */
-		mutex_lock(&board_lock);
-		id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
-			ctlr->bus_num + 1, GFP_KERNEL);
-		mutex_unlock(&board_lock);
-		if (WARN(id < 0, "couldn't get idr"))
-			return id == -ENOSPC ? -EBUSY : id;
-		ctlr->bus_num = id;
+		status = spi_controller_id_alloc(ctlr, ctlr->bus_num, ctlr->bus_num + 1);
+		if (status)
+			return status;
 	} else {
 		/* Allocate dynamic bus number using Linux idr */
 		id = of_alias_get_id(ctlr->dev.of_node, "spi");
 		if (id >= 0) {
-			ctlr->bus_num = id;
-			mutex_lock(&board_lock);
-			id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
-				       ctlr->bus_num + 1, GFP_KERNEL);
-			mutex_unlock(&board_lock);
-			if (WARN(id < 0, "couldn't get idr"))
-				return id == -ENOSPC ? -EBUSY : id;
+			status = spi_controller_id_alloc(ctlr, id, id + 1);
+			if (status)
+				return status;
 		}
 	}
 	if (ctlr->bus_num < 0) {
@@ -3151,13 +3157,9 @@ int spi_register_controller(struct spi_controller *ctlr)
 		else
 			first_dynamic++;
 
-		mutex_lock(&board_lock);
-		id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
-			       0, GFP_KERNEL);
-		mutex_unlock(&board_lock);
-		if (WARN(id < 0, "couldn't get idr"))
-			return id;
-		ctlr->bus_num = id;
+		status = spi_controller_id_alloc(ctlr, first_dynamic, 0);
+		if (status)
+			return status;
 	}
 	ctlr->bus_lock_flag = 0;
 	init_completion(&ctlr->xfer_completion);
-- 
2.40.0.1.gaa8946217a0b