linux-kernel - Re: [PATCH 4/4] cxgb4: remove redundant NULL check

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Message-ID: <20210127035604.GA21071@chelsio.com>
Date:   Wed, 27 Jan 2021 09:26:06 +0530
From:   Raju Rangoju <rajur@...lsio.com>
To:     Yang Li <abaci-bugfix@...ux.alibaba.com>
Cc:     davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] cxgb4: remove redundant NULL check

On Monday, January 01/25/21, 2021 at 17:47:25 +0800, Yang Li wrote:
> Fix below warnings reported by coccicheck:
>  ./drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_u32.c:533:2-8: WARNING:
> NULL check before some freeing functions is not needed.
> 
> Reported-by: Abaci Robot <abaci@...ux.alibaba.com>
> Signed-off-by: Yang Li <abaci-bugfix@...ux.alibaba.com>
> ---
>  drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_u32.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_u32.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_u32.c
> index dede025..97a811f 100644
> --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_u32.c
> +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_u32.c
> @@ -525,12 +525,10 @@ struct cxgb4_tc_u32_table *cxgb4_init_tc_u32(struct adapter *adap)
>  	for (i = 0; i < t->size; i++) {
>  		struct cxgb4_link *link = &t->table[i];
>  
> -		if (link->tid_map)
> -			kvfree(link->tid_map);

This patch is wrong. NAK.

What if the call to link->tid_map = kvcalloc() fails above? it still goes ahead
and calls kvfree(link->tid_map), which is wrong.


> +		kvfree(link->tid_map);
>  	}
>  
> -	if (t)
> -		kvfree(t);
> +	kvfree(t);
>  
>  	return NULL;
>  }
> -- 
> 1.8.3.1
>