[dpdk-dev] [PATCH 1/2 v2] bnxt: use appropriate data type in bnxt_alloc_vnic_attributes

[Ferruh Yigit]

On 11/3/2016 6:58 PM, Ajit Khaparde wrote:
> Prevent the arithmetic in bnxt_alloc_vnic_attributes from causing
> any unintentional havoc because of the usage of a signed variable.
> 
> Coverity: 137874
> 
> Signed-off-by: Ajit Khaparde <ajit.khaparde at broadcom.com>
> 
> --
> v2: Previous attempt did not seem complete.
> ---
>  drivers/net/bnxt/bnxt_vnic.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/bnxt/bnxt_vnic.c b/drivers/net/bnxt/bnxt_vnic.c
> index 205a940..23c85af 100644
> --- a/drivers/net/bnxt/bnxt_vnic.c
> +++ b/drivers/net/bnxt/bnxt_vnic.c
> @@ -179,7 +179,7 @@ int bnxt_alloc_vnic_attributes(struct bnxt *bp)
>  				HW_HASH_INDEX_SIZE * sizeof(*vnic->rss_table) +
>  				HW_HASH_KEY_SIZE);
>  	uint16_t max_vnics;
> -	int i;
> +	uint16_t i;
>  
>  	if (BNXT_PF(bp)) {
>  		struct bnxt_pf_info *pf = &bp->pf;
> @@ -197,7 +197,7 @@ int bnxt_alloc_vnic_attributes(struct bnxt *bp)
>  	mz = rte_memzone_lookup(mz_name);
>  	if (!mz) {
>  		mz = rte_memzone_reserve(mz_name,
> -					 entry_length * max_vnics,
> +					 (uint32_t) entry_length * max_vnics,
>  					 SOCKET_ID_ANY,
>  					 RTE_MEMZONE_2MB |
>  					 RTE_MEMZONE_SIZE_HINT_ONLY);
> @@ -210,10 +210,11 @@ int bnxt_alloc_vnic_attributes(struct bnxt *bp)
>  
>  		/* Allocate rss table and hash key */
>  		vnic->rss_table =
> -			(void *)((char *)mz->addr + (entry_length * i));
> +		(void *)((char *)mz->addr + ((uint32_t) entry_length * i));
>  		memset(vnic->rss_table, -1, entry_length);
>  
> -		vnic->rss_table_dma_addr = mz->phys_addr + (entry_length * i);
> +		vnic->rss_table_dma_addr =
> +			mz->phys_addr + ((uint32_t) entry_length * i);

((uint32_t) entry_length * i)
casting entry_length to uint32_t will prevent the integer promotion and
fix the coverity issue, but if this is the case, why not make
entry_length uint32_t at first place?

It seems "entry_length" converted from "int" to "uint16_t" to prevent
integer promotion (e8a197d2aa9a), but
"entry_length * max_vnics" => "uint16_t * uint16_t" or
"entry_length * i" => "uint16_t * int"
still causing the promotion.

I guess converting "entry_length" to uint32_t (instead of uint16_t) will
fix both triaged 127557 and new introduced 137874 coverity issues, and
it is simpler modification, - if I don't miss anything J

Thanks,
ferruh


>  		vnic->rss_hash_key = (void *)((char *)vnic->rss_table +
>  			     HW_HASH_INDEX_SIZE * sizeof(*vnic->rss_table));
>  
>