[PATCH 0/5] usb: gadget: udc: Convert to platform remove callback returning void

[PATCH 0/5] usb: gadget: udc: Convert to platform remove callback returning void

[Uwe Kleine-König]

Hello,

this patch set converts the platform drivers below drivers/usb/gadget to
use .remove_new. These drivers all have an error path if the driver is
still in use. Returning there early leaks resources, but fixing this
isn't trivial, so I just added an error message. The patches don't make
a difference to the drivers apart from the improved error message.

See commit 5c5a7680e67b ("platform: Provide a remove callback that
returns no value") for an extended explanation and the eventual goal of
.remove_new().

Best regards
Uwe

Uwe Kleine-König (5):
  usb: gadget: at91_udc: Convert to platform remove callback returning void
  usb: gadget: fsl_udc: Convert to platform remove callback returning void
  usb: gadget: gr_udc: Convert to platform remove callback returning void
  usb: gadget: lpc32xx_udc: Convert to platform remove callback returning void
  usb: gadget: pxa25x_udc: Convert to platform remove callback returning void

 drivers/usb/gadget/udc/at91_udc.c     | 13 +++++++------
 drivers/usb/gadget/udc/fsl_udc_core.c | 13 +++++++------
 drivers/usb/gadget/udc/gr_udc.c       | 13 +++++++------
 drivers/usb/gadget/udc/lpc32xx_udc.c  | 13 +++++++------
 drivers/usb/gadget/udc/pxa25x_udc.c   | 12 +++++++-----
 5 files changed, 35 insertions(+), 29 deletions(-)

base-commit: 5a82d69d48c82e89aef44483d2a129f869f3506a
-- 
2.42.0

[PATCH 2/5] usb: gadget: fsl_udc: Convert to platform remove callback returning void

[Uwe Kleine-König]

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

In the error path emit an error message replacing the (less useful)
message by the core. Apart from the improved error message there is no
change in behaviour.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/usb/gadget/udc/fsl_udc_core.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/gadget/udc/fsl_udc_core.c b/drivers/usb/gadget/udc/fsl_udc_core.c
index 2693a10eb0c7..535b6e79a198 100644
--- a/drivers/usb/gadget/udc/fsl_udc_core.c
+++ b/drivers/usb/gadget/udc/fsl_udc_core.c
@@ -2532,15 +2532,18 @@ static int fsl_udc_probe(struct platform_device *pdev)
 /* Driver removal function
  * Free resources and finish pending transactions
  */
-static int fsl_udc_remove(struct platform_device *pdev)
+static void fsl_udc_remove(struct platform_device *pdev)
 {
 	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	struct fsl_usb2_platform_data *pdata = dev_get_platdata(&pdev->dev);
 
 	DECLARE_COMPLETION_ONSTACK(done);
 
-	if (!udc_controller)
-		return -ENODEV;
+	if (!udc_controller) {
+		dev_err(&pdev->dev,
+			"Driver still in use but removing anyhow\n");
+		return;
+	}
 
 	udc_controller->done = &done;
 	usb_del_gadget_udc(&udc_controller->gadget);
@@ -2568,8 +2571,6 @@ static int fsl_udc_remove(struct platform_device *pdev)
 	 */
 	if (pdata->exit)
 		pdata->exit(pdev);
-
-	return 0;
 }
 
 /*-----------------------------------------------------------------
@@ -2667,7 +2668,7 @@ static const struct platform_device_id fsl_udc_devtype[] = {
 MODULE_DEVICE_TABLE(platform, fsl_udc_devtype);
 static struct platform_driver udc_driver = {
 	.probe		= fsl_udc_probe,
-	.remove		= fsl_udc_remove,
+	.remove_new	= fsl_udc_remove,
 	.id_table	= fsl_udc_devtype,
 	/* these suspend and resume are not usb suspend and resume */
 	.suspend	= fsl_udc_suspend,
-- 
2.42.0