Re: [net-intel-i40e] question about assignment overwrite

[Jeff Kirsher]

On Wed, 2017-05-17 at 15:48 -0500, Gustavo A. R. Silva wrote:
> While looking into Coverity ID 1408956 I ran into the following
> pieceÂÂ
> of code at drivers/net/ethernet/intel/i40e/i40e_main.c:8807:
> 
> 8807ÂÂÂÂÂÂÂ if (pf->hw.mac.type == I40E_MAC_X722) {
> 8808ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pf->flags |= I40E_FLAG_RSS_AQ_CAPABLE
> 8809ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_128_QP_RSS_CAPABLE
> 8810ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_HW_ATR_EVICT_CAPABLE
> 8811ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_OUTER_UDP_CSUM_CAPABLE
> 8812ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_WB_ON_ITR_CAPABLE
> 8813ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |
> I40E_FLAG_MULTIPLE_TCP_UDP_RSS_PCTYPE
> 8814ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_NO_PCI_LINK_CHECK
> 8815ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_USE_SET_LLDP_MIB
> 8816ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_GENEVE_OFFLOAD_CAPABLE
> 8817ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_PTP_L4_CAPABLE
> 8818ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | I40E_FLAG_WOL_MC_MAGIC_PKT_WAKE;
> 8819ÂÂÂÂÂÂÂ } else if ((pf->hw.aq.api_maj_ver > 1) ||
> 8820ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ((pf->hw.aq.api_maj_ver == 1) &&
> 8821ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ (pf->hw.aq.api_min_ver > 4))) {
> 8822ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Supported in FW API version higher than 1.4 */
> 8823ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pf->flags |= I40E_FLAG_GENEVE_OFFLOAD_CAPABLE;
> 8824ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pf->flags = I40E_FLAG_HW_ATR_EVICT_CAPABLE;
> 8825ÂÂÂÂÂÂÂ } else {
> 8826ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pf->flags = I40E_FLAG_HW_ATR_EVICT_CAPABLE;
> 8827ÂÂÂÂÂÂÂ }
> 
> The issue here is that the assignment at line 8823 is overwritten
> byÂÂ
> the code at line 8824.
> 
> I'm suspicious that line 8824 should be remove and a patch like theÂÂ
> following can be applied:
> 
> index d5c9c9e..48ffa73 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -8821,7 +8821,6 @@ static int i40e_sw_init(struct i40e_pf *pf)
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ (pf->hw.aq.api_min_ver > 4))) {
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Supported in FW API version higher than 1.4 */
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pf->flags |= I40E_FLAG_GENEVE_OFFLOAD_CAPABLE;
> -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pf->flags = I40E_FLAG_HW_ATR_EVICT_CAPABLE;
> ÂÂÂÂÂÂÂÂ } else {
> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ pf->flags = I40E_FLAG_HW_ATR_EVICT_CAPABLE;
> ÂÂÂÂÂÂÂÂ }
> 
> What do you think?

This issue is already fixed in my dev-queue branch on my next-queue
tree.

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