linux-kernel - Re: [PATCH][next] dma-buf: heaps: remove redundant assignment to variable ret

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Date:   Wed, 30 Oct 2019 11:45:29 -0400
From:   "Andrew F. Davis" <afd@...com>
To:     Colin King <colin.king@...onical.com>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Liam Mark <lmark@...eaurora.org>,
        Laura Abbott <labbott@...hat.com>,
        Brian Starkey <brian.starkey@....com>,
        John Stultz <john.stultz@...aro.org>,
        <linux-media@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        <linaro-mm-sig@...ts.linaro.org>
CC:     <kernel-janitors@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH][next] dma-buf: heaps: remove redundant assignment to
 variable ret

On 10/30/19 11:02 AM, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The variable ret is being assigned with a value that is never
> read, it is being re-assigned the same value on the err0 exit
> path. The assignment is redundant and hence can be removed.
> 
> Addresses-Coverity: ("Unused value")
> Fixes: 47a32f9c1226 ("dma-buf: heaps: Add system heap to dmabuf heaps")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---


The root of the issue is that ret is not used in the error path, it
should be, I suggest this fix:

> --- a/drivers/dma-buf/heaps/system_heap.c
> +++ b/drivers/dma-buf/heaps/system_heap.c
> @@ -98,7 +98,7 @@ static int system_heap_allocate(struct dma_heap *heap,
>  err0:
>         kfree(helper_buffer);
>  
> -       return -ENOMEM;
> +       return ret;
>  }
>  
>  static const struct dma_heap_ops system_heap_ops = {

Andrew


>  drivers/dma-buf/heaps/system_heap.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
> index 455782efbb32..817a1667bd57 100644
> --- a/drivers/dma-buf/heaps/system_heap.c
> +++ b/drivers/dma-buf/heaps/system_heap.c
> @@ -55,10 +55,8 @@ static int system_heap_allocate(struct dma_heap *heap,
>  	helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
>  					     sizeof(*helper_buffer->pages),
>  					     GFP_KERNEL);
> -	if (!helper_buffer->pages) {
> -		ret = -ENOMEM;
> +	if (!helper_buffer->pages)
>  		goto err0;
> -	}
>  
>  	for (pg = 0; pg < helper_buffer->pagecount; pg++) {
>  		/*
>