Re: [dpdk-dev] [PATCH] lpm: fix extended flag check when adding a "depth small" entry

["Liang, Cunming" <cunming.liang@intel.com>]

On 7/28/2015 5:14 PM, Zhe Tao wrote:
> When adding a "depth small" entry, if its extended flag is not set
> and its depth is smaller than the one in the tbl24, nothing should
> be done otherwise will operate on the wrong memory area.
>
> Signed-off-by: Zhe Tao <zhe.tao@intel.com>
> ---
>   lib/librte_lpm/rte_lpm.c | 51 +++++++++++++++++++++++++-----------------------
>   1 file changed, 27 insertions(+), 24 deletions(-)
>
> diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
> index de05307..0ef2421 100644
> --- a/lib/librte_lpm/rte_lpm.c
> +++ b/lib/librte_lpm/rte_lpm.c
> @@ -447,30 +447,33 @@ add_depth_small(struct rte_lpm *lpm, uint32_t ip, uint8_t depth,
>   
>   			continue;
>   		}
> -
> -		/* If tbl24 entry is valid and extended calculate the index
> -		 * into tbl8. */
> -		tbl8_index = lpm->tbl24[i].tbl8_gindex *
> -				RTE_LPM_TBL8_GROUP_NUM_ENTRIES;
> -		tbl8_group_end = tbl8_index + RTE_LPM_TBL8_GROUP_NUM_ENTRIES;
> -
> -		for (j = tbl8_index; j < tbl8_group_end; j++) {
> -			if (!lpm->tbl8[j].valid ||
> -					lpm->tbl8[j].depth <= depth) {
> -				struct rte_lpm_tbl8_entry new_tbl8_entry = {
> -					.valid = VALID,
> -					.valid_group = VALID,
> -					.depth = depth,
> -					.next_hop = next_hop,
> -				};
> -
> -				/*
> -				 * Setting tbl8 entry in one go to avoid race
> -				 * conditions
> -				 */
> -				lpm->tbl8[j] = new_tbl8_entry;
> -
> -				continue;
> +
> +		if (lpm->tbl24[i].ext_entry == 1) {
> +
> +			/* If tbl24 entry is valid and extended calculate the index
> +			 * into tbl8. */
One minor comment on the format. Some lines are over 80 characters and 
the blank line ahead of the comment is not required.
> +			tbl8_index = lpm->tbl24[i].tbl8_gindex *
> +					RTE_LPM_TBL8_GROUP_NUM_ENTRIES;
> +			tbl8_group_end = tbl8_index + RTE_LPM_TBL8_GROUP_NUM_ENTRIES;
> +
> +			for (j = tbl8_index; j < tbl8_group_end; j++) {
> +				if (!lpm->tbl8[j].valid ||
> +						lpm->tbl8[j].depth <= depth) {
> +					struct rte_lpm_tbl8_entry new_tbl8_entry = {
> +						.valid = VALID,
> +						.valid_group = VALID,
> +						.depth = depth,
> +						.next_hop = next_hop,
> +					};
> +
> +					/*
> +					 * Setting tbl8 entry in one go to avoid race
> +					 * conditions
> +					 */
> +					lpm->tbl8[j] = new_tbl8_entry;
> +
> +					continue;
> +				}
>   			}
>   		}
>   	}