crypto: qat - Return pointer directly in adf_ctl_alloc_resources

Returning values through arguments is confusing and that has
upset the compiler with the recent change to memdup_user:

../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c: In function ‘adf_ctl_ioctl’:
../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c:308:26: warning: ‘ctl_data’ may be used uninitialized [-Wmaybe-uninitialized]
  308 |                  ctl_data->device_id);
      |                          ^~
../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c:294:39: note: ‘ctl_data’ was declared here
  294 |         struct adf_user_cfg_ctl_data *ctl_data;
      |                                       ^~~~~~~~
In function ‘adf_ctl_ioctl_dev_stop’,
    inlined from ‘adf_ctl_ioctl’ at ../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c:386:9:
../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c:273:48: warning: ‘ctl_data’ may be used uninitialized [-Wmaybe-uninitialized]
  273 |         ret = adf_ctl_is_device_in_use(ctl_data->device_id);
      |                                        ~~~~~~~~^~~~~~~~~~~
../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c: In function ‘adf_ctl_ioctl’:
../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c:261:39: note: ‘ctl_data’ was declared here
  261 |         struct adf_user_cfg_ctl_data *ctl_data;
      |                                       ^~~~~~~~
In function ‘adf_ctl_ioctl_dev_config’,
    inlined from ‘adf_ctl_ioctl’ at ../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c:382:9:
../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c:192:54: warning: ‘ctl_data’ may be used uninitialized [-Wmaybe-uninitialized]
  192 |         accel_dev = adf_devmgr_get_dev_by_id(ctl_data->device_id);
      |                                              ~~~~~~~~^~~~~~~~~~~
../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c: In function ‘adf_ctl_ioctl’:
../drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c:185:39: note: ‘ctl_data’ was declared here
  185 |         struct adf_user_cfg_ctl_data *ctl_data;
      |                                       ^~~~~~~~

Fix this by returning the pointer directly.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Thorsten Blum <thorsten.blum@linux.dev>
Acked-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Author: herbertx

drivers/crypto/intel/qat/qat_common/adf_ctl_drv.c

@@ -89,19 +89,14 @@ static int adf_chr_drv_create(void)
 	return -EFAULT;
 }
 
-static int adf_ctl_alloc_resources(struct adf_user_cfg_ctl_data **ctl_data,
-				   unsigned long arg)
+static struct adf_user_cfg_ctl_data *adf_ctl_alloc_resources(unsigned long arg)
 {
 	struct adf_user_cfg_ctl_data *cfg_data;
 
 	cfg_data = memdup_user((void __user *)arg, sizeof(*cfg_data));
-	if (IS_ERR(cfg_data)) {
+	if (IS_ERR(cfg_data))
 		pr_err("QAT: failed to copy from user cfg_data.\n");
-		return PTR_ERR(cfg_data);
-	}
-
-	*ctl_data = cfg_data;
-	return 0;
+	return cfg_data;
 }
 
 static int adf_add_key_value_data(struct adf_accel_dev *accel_dev,
@@ -181,13 +176,13 @@ static int adf_copy_key_value_data(struct adf_accel_dev *accel_dev,
 static int adf_ctl_ioctl_dev_config(struct file *fp, unsigned int cmd,
 				    unsigned long arg)
 {
-	int ret;
 	struct adf_user_cfg_ctl_data *ctl_data;
 	struct adf_accel_dev *accel_dev;
+	int ret = 0;
 
-	ret = adf_ctl_alloc_resources(&ctl_data, arg);
-	if (ret)
-		return ret;
+	ctl_data = adf_ctl_alloc_resources(arg);
+	if (IS_ERR(ctl_data))
+		return PTR_ERR(ctl_data);
 
 	accel_dev = adf_devmgr_get_dev_by_id(ctl_data->device_id);
 	if (!accel_dev) {
@@ -260,9 +255,9 @@ static int adf_ctl_ioctl_dev_stop(struct file *fp, unsigned int cmd,
 	int ret;
 	struct adf_user_cfg_ctl_data *ctl_data;
 
-	ret = adf_ctl_alloc_resources(&ctl_data, arg);
-	if (ret)
-		return ret;
+	ctl_data = adf_ctl_alloc_resources(arg);
+	if (IS_ERR(ctl_data))
+		return PTR_ERR(ctl_data);
 
 	if (adf_devmgr_verify_id(ctl_data->device_id)) {
 		pr_err("QAT: Device %d not found\n", ctl_data->device_id);
@@ -294,9 +289,9 @@ static int adf_ctl_ioctl_dev_start(struct file *fp, unsigned int cmd,
 	struct adf_user_cfg_ctl_data *ctl_data;
 	struct adf_accel_dev *accel_dev;
 
-	ret = adf_ctl_alloc_resources(&ctl_data, arg);
-	if (ret)
-		return ret;
+	ctl_data = adf_ctl_alloc_resources(arg);
+	if (IS_ERR(ctl_data))
+		return PTR_ERR(ctl_data);
 
 	ret = -ENODEV;
 	accel_dev = adf_devmgr_get_dev_by_id(ctl_data->device_id);