crypto: caam/jr - Convert to platform remove callback returning void

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 (mostly) ignored
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.

The driver adapted here suffers from this wrong assumption. Returning
-EBUSY if there are still users results in resource leaks and probably a
crash. Also further down passing the error code of caam_jr_shutdown() to
the caller only results in another error message and has no further
consequences compared to returning zero.

Still convert the driver to return no value in the remove callback. This
also allows to drop caam_jr_platform_shutdown() as the only function
called by it now has the same prototype.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/jr.c

@@ -180,7 +180,7 @@ static int caam_jr_shutdown(struct device *dev)
 	return ret;
 }
 
-static int caam_jr_remove(struct platform_device *pdev)
+static void caam_jr_remove(struct platform_device *pdev)
 {
 	int ret;
 	struct device *jrdev;
@@ -193,11 +193,14 @@ static int caam_jr_remove(struct platform_device *pdev)
 		caam_rng_exit(jrdev->parent);
 
 	/*
-	 * Return EBUSY if job ring already allocated.
+	 * If a job ring is still allocated there is trouble ahead. Once
+	 * caam_jr_remove() returned, jrpriv will be freed and the registers
+	 * will get unmapped. So any user of such a job ring will probably
+	 * crash.
 	 */
 	if (atomic_read(&jrpriv->tfm_count)) {
-		dev_err(jrdev, "Device is busy\n");
-		return -EBUSY;
+		dev_alert(jrdev, "Device is busy; consumers might start to crash\n");
+		return;
 	}
 
 	/* Unregister JR-based RNG & crypto algorithms */
@@ -212,13 +215,6 @@ static int caam_jr_remove(struct platform_device *pdev)
 	ret = caam_jr_shutdown(jrdev);
 	if (ret)
 		dev_err(jrdev, "Failed to shut down job ring\n");
-
-	return ret;
-}
-
-static void caam_jr_platform_shutdown(struct platform_device *pdev)
-{
-	caam_jr_remove(pdev);
 }
 
 /* Main per-ring interrupt handler */
@@ -823,8 +819,8 @@ static struct platform_driver caam_jr_driver = {
 		.pm = pm_ptr(&caam_jr_pm_ops),
 	},
 	.probe       = caam_jr_probe,
-	.remove      = caam_jr_remove,
-	.shutdown    = caam_jr_platform_shutdown,
+	.remove_new  = caam_jr_remove,
+	.shutdown    = caam_jr_remove,
 };
 
 static int __init jr_driver_init(void)