linux-kernel - Re: [PATCH 1/4] drivers/misc/sgi-gru: remove unused variable

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Date:	Wed, 2 Sep 2015 09:42:04 -0500
From:	Dimitri Sivanich <sivanich@....com>
To:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
Cc:	Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] drivers/misc/sgi-gru: remove unused variable

On Wed, Sep 02, 2015 at 04:54:55PM +0530, Sudip Mukherjee wrote:
> These variables were only assigned some value and were never used.
> 
> Signed-off-by: Sudip Mukherjee <sudip@...torindia.org>
> ---
> 
> I have removed the variables in the functions gru_dump_tfm() and
> gru_dump_tgh() but it appeared that the intended logic might have been
> something like:
> bytes = GRU_NUM_TFM * GRU_CACHE_LINE_BYTES;
> if (bytes > ubufend - ubuf)
> 	return -EFBIG;
> 
> But since I was not sure so removing the variable was the safe choice as
> it is not changing the logic.

I think better would be as shown below.
> 
>  drivers/misc/sgi-gru/grukdump.c     | 12 ++----------
>  drivers/misc/sgi-gru/grukservices.c |  2 --
>  2 files changed, 2 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/misc/sgi-gru/grukdump.c b/drivers/misc/sgi-gru/grukdump.c
> index a3700a5..fa515e3 100644
> --- a/drivers/misc/sgi-gru/grukdump.c
> +++ b/drivers/misc/sgi-gru/grukdump.c
> @@ -78,11 +78,7 @@ static int gru_dump_tfm(struct gru_state *gru,
>  		void __user *ubuf, void __user *ubufend)
>  {
>  	struct gru_tlb_fault_map *tfm;
> -	int i, ret, bytes;
> -
> -	bytes = GRU_NUM_TFM * GRU_CACHE_LINE_BYTES;
> -	if (bytes > ubufend - ubuf)
> -		ret = -EFBIG;
> +	int i;
+
+ 	if ((GRU_NUM_TFM * GRU_CACHE_LINE_BYTES) > (ubufend - ubuf))
+		return -EFBIG;
>  
>  	for (i = 0; i < GRU_NUM_TFM; i++) {
>  		tfm = get_tfm(gru->gs_gru_base_vaddr, i);
> @@ -99,11 +95,7 @@ static int gru_dump_tgh(struct gru_state *gru,
>  		void __user *ubuf, void __user *ubufend)
>  {
>  	struct gru_tlb_global_handle *tgh;
> -	int i, ret, bytes;
> -
> -	bytes = GRU_NUM_TGH * GRU_CACHE_LINE_BYTES;
> -	if (bytes > ubufend - ubuf)
> -		ret = -EFBIG;
> +	int i;

(Same as shown above)
>  
>  	for (i = 0; i < GRU_NUM_TGH; i++) {
>  		tgh = get_tgh(gru->gs_gru_base_vaddr, i);
> diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c
> index 913de07..1f0bdab 100644
> --- a/drivers/misc/sgi-gru/grukservices.c
> +++ b/drivers/misc/sgi-gru/grukservices.c
> @@ -997,7 +997,6 @@ static int quicktest1(unsigned long arg)
>  {
>  	struct gru_message_queue_desc mqd;
>  	void *p, *mq;
> -	unsigned long *dw;
>  	int i, ret = -EIO;
>  	char mes[GRU_CACHE_LINE_BYTES], *m;
>  
> @@ -1007,7 +1006,6 @@ static int quicktest1(unsigned long arg)
>  		return -ENOMEM;
>  	mq = ALIGNUP(p, 1024);
>  	memset(mes, 0xee, sizeof(mes));
> -	dw = mq;
>  
>  	gru_create_message_queue(&mqd, mq, 8 * GRU_CACHE_LINE_BYTES, 0, 0, 0);
>  	for (i = 0; i < 6; i++) {
> -- 
> 1.9.1
--
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