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Date: Mon, 16 Aug 2010 22:43:25 +0200 (CEST)
From: Julia Lawall <julia@diku.dk>
To: Jonathan Woithe <jwoithe@physics.adelaide.edu.au>
Cc: Matthew Garrett <mjg@redhat.com>, platform-driver-x86@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH 15/16] drivers/platform/x86: Use available error codes
In-Reply-To: <201008161711.o7GHBw0x007457@mercury.physics.adelaide.edu.au>
Message-ID: <Pine.LNX.4.64.1008162243120.12526@ask.diku.dk>
References: <201008161711.o7GHBw0x007457@mercury.physics.adelaide.edu.au>
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Looks ok to me.  Thanks.

julia

On Tue, 17 Aug 2010, Jonathan Woithe wrote:

> I've had a quick look at this and the idea behind it is sound.  While it
> does change the symantics as noted in the original post, the change is only
> in an error path and to my eye the error code should be returned in that
> case - as the code currently stands a 0 is returned even if ENOMEM has
> occurred.
> 
> It seems to me that error and result have been (wrongly) used interchangedly
> within these two functions (possibly be different authors).  I agree that
> one of them should be eliminated, and error seems the sensible choice.  So
> something like the following is probably in order.
> 
> ===
> 
> An error code is stored in the variable error, but it is the variable result
> that is returned instead.  So store the error code in result and eliminate
> the unnecessary variable error.  Initial report and patch from Julia Lawall
> <julia@diku.dk>.
> 
> The semantic match that finds this problem is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @r@
> local idexpression x;
> constant C;
> @@
> 
> if (...) { ...
>   x = -C
>   ... when != x
> (
>   return <+...x...+>;
> |
>   return NULL;
> |
>   return;
> |
> * return ...;
> )
> }
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>
> Signed-off-by: Jonathan Woithe <jwoithe@physics.adelaide.edu.au>
> 
> --- a/drivers/platform/x86/fujitsu-laptop.c	2010-03-16 02:39:39.000000000 +1030
> +++ b/drivers/platform/x86/fujitsu-laptop.c	2010-08-17 02:37:18.556779664 +0930
> @@ -655,7 +655,6 @@
>  	int result = 0;
>  	int state = 0;
>  	struct input_dev *input;
> -	int error;
>  
>  	if (!device)
>  		return -EINVAL;
> @@ -667,7 +666,7 @@
>  
>  	fujitsu->input = input = input_allocate_device();
>  	if (!input) {
> -		error = -ENOMEM;
> +		result = -ENOMEM;
>  		goto err_stop;
>  	}
>  
> @@ -684,8 +683,8 @@
>  	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
>  	set_bit(KEY_UNKNOWN, input->keybit);
>  
> -	error = input_register_device(input);
> -	if (error)
> +	result = input_register_device(input);
> +	if (result)
>  		goto err_free_input_dev;
>  
>  	result = acpi_bus_get_power(fujitsu->acpi_handle, &state);
> @@ -810,7 +809,6 @@
>  	int result = 0;
>  	int state = 0;
>  	struct input_dev *input;
> -	int error;
>  	int i;
>  
>  	if (!device)
> @@ -824,16 +822,16 @@
>  
>  	/* kfifo */
>  	spin_lock_init(&fujitsu_hotkey->fifo_lock);
> -	error = kfifo_alloc(&fujitsu_hotkey->fifo, RINGBUFFERSIZE * sizeof(int),
> +	result = kfifo_alloc(&fujitsu_hotkey->fifo, RINGBUFFERSIZE * sizeof(int),
>  			GFP_KERNEL);
> -	if (error) {
> +	if (result) {
>  		printk(KERN_ERR "kfifo_alloc failed\n");
>  		goto err_stop;
>  	}
>  
>  	fujitsu_hotkey->input = input = input_allocate_device();
>  	if (!input) {
> -		error = -ENOMEM;
> +		result = -ENOMEM;
>  		goto err_free_fifo;
>  	}
>  
> @@ -853,8 +851,8 @@
>  	set_bit(fujitsu->keycode4, input->keybit);
>  	set_bit(KEY_UNKNOWN, input->keybit);
>  
> -	error = input_register_device(input);
> -	if (error)
> +	result = input_register_device(input);
> +	if (result)
>  		goto err_free_input_dev;
>  
>  	result = acpi_bus_get_power(fujitsu_hotkey->acpi_handle, &state);
> --
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