diff mbox series

[3/3] usb: gadget: f_hid: tidy error handling in hidg_alloc

Message ID 20221122123523.3068034-4-john@metanate.com
State New
Headers
Series usb: gadget: f_hid: fix f_hidg lifetime vs cdev |

Commit Message

John Keeping Nov. 22, 2022, 12:35 p.m. UTC 
  Unify error handling at the end of the function, reducing the risk of
missing something on one of the error paths.

Moving the increment of opts->refcnt later means there is no need to
decrement it on the error path and is safe as this is guarded by
opts->lock which is held for this entire section.

Signed-off-by: John Keeping <john@metanate.com>
---
 drivers/usb/gadget/function/f_hid.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

Comments

Andrzej Pietrasiewicz Nov. 23, 2022, 12:19 p.m. UTC | #1 
W dniu 22.11.2022 o 13:35, John Keeping pisze:
> Unify error handling at the end of the function, reducing the risk of
> missing something on one of the error paths.
> 
> Moving the increment of opts->refcnt later means there is no need to
> decrement it on the error path and is safe as this is guarded by
> opts->lock which is held for this entire section.
> 
> Signed-off-by: John Keeping <john@metanate.com>

Reviewed-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
>   drivers/usb/gadget/function/f_hid.c | 21 +++++++++++----------
>   1 file changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
> index 6be6009f911e..a8da3b4a2855 100644
> --- a/drivers/usb/gadget/function/f_hid.c
> +++ b/drivers/usb/gadget/function/f_hid.c
> @@ -1269,18 +1269,14 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
>   	opts = container_of(fi, struct f_hid_opts, func_inst);
>   
>   	mutex_lock(&opts->lock);
> -	++opts->refcnt;
>   
>   	device_initialize(&hidg->dev);
>   	hidg->dev.release = hidg_release;
>   	hidg->dev.class = hidg_class;
>   	hidg->dev.devt = MKDEV(major, opts->minor);
>   	ret = dev_set_name(&hidg->dev, "hidg%d", opts->minor);
> -	if (ret) {
> -		--opts->refcnt;
> -		mutex_unlock(&opts->lock);
> -		return ERR_PTR(ret);
> -	}
> +	if (ret)
> +		goto err_unlock;
>   
>   	hidg->bInterfaceSubClass = opts->subclass;
>   	hidg->bInterfaceProtocol = opts->protocol;
> @@ -1291,14 +1287,13 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
>   						 opts->report_desc_length,
>   						 GFP_KERNEL);
>   		if (!hidg->report_desc) {
> -			put_device(&hidg->dev);
> -			--opts->refcnt;
> -			mutex_unlock(&opts->lock);
> -			return ERR_PTR(-ENOMEM);
> +			ret = -ENOMEM;
> +			goto err_put_device;
>   		}
>   	}
>   	hidg->use_out_ep = !opts->no_out_endpoint;
>   
> +	++opts->refcnt;
>   	mutex_unlock(&opts->lock);
>   
>   	hidg->func.name    = "hid";
> @@ -1313,6 +1308,12 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
>   	hidg->qlen	   = 4;
>   
>   	return &hidg->func;
> +
> +err_put_device:
> +	put_device(&hidg->dev);
> +err_unlock:
> +	mutex_unlock(&opts->lock);
> +	return ERR_PTR(ret);
>   }
>   
>   DECLARE_USB_FUNCTION_INIT(hid, hidg_alloc_inst, hidg_alloc);
diff mbox series

Patch

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index 6be6009f911e..a8da3b4a2855 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -1269,18 +1269,14 @@  static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
 	opts = container_of(fi, struct f_hid_opts, func_inst);
 
 	mutex_lock(&opts->lock);
-	++opts->refcnt;
 
 	device_initialize(&hidg->dev);
 	hidg->dev.release = hidg_release;
 	hidg->dev.class = hidg_class;
 	hidg->dev.devt = MKDEV(major, opts->minor);
 	ret = dev_set_name(&hidg->dev, "hidg%d", opts->minor);
-	if (ret) {
-		--opts->refcnt;
-		mutex_unlock(&opts->lock);
-		return ERR_PTR(ret);
-	}
+	if (ret)
+		goto err_unlock;
 
 	hidg->bInterfaceSubClass = opts->subclass;
 	hidg->bInterfaceProtocol = opts->protocol;
@@ -1291,14 +1287,13 @@  static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
 						 opts->report_desc_length,
 						 GFP_KERNEL);
 		if (!hidg->report_desc) {
-			put_device(&hidg->dev);
-			--opts->refcnt;
-			mutex_unlock(&opts->lock);
-			return ERR_PTR(-ENOMEM);
+			ret = -ENOMEM;
+			goto err_put_device;
 		}
 	}
 	hidg->use_out_ep = !opts->no_out_endpoint;
 
+	++opts->refcnt;
 	mutex_unlock(&opts->lock);
 
 	hidg->func.name    = "hid";
@@ -1313,6 +1308,12 @@  static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
 	hidg->qlen	   = 4;
 
 	return &hidg->func;
+
+err_put_device:
+	put_device(&hidg->dev);
+err_unlock:
+	mutex_unlock(&opts->lock);
+	return ERR_PTR(ret);
 }
 
 DECLARE_USB_FUNCTION_INIT(hid, hidg_alloc_inst, hidg_alloc);