Re: [dpdk-dev] [PATCH v2 2/2] lib/lpm:fix an initialization issue of valid_group in the delete_depth_small()

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Oct 30, 2015 at 09:14:39PM +0800, Jijiang Liu wrote:

Title can be shortened to: "lpm: fix initialization of valid_group field"

> Fixes an initialization issue of 'valid_group' in the delete_depth_small function.
> 
> In this function, use new rte_lpm_tbl8_entry we call A to replace the old rte_lpm_tbl8_entry. But the valid_group do not set VALID, so it 
> will be INVALID.
> 
> Then when adding a new route which depth is > 24,the tbl8_alloc() function will search the rte_lpm_tbl8_entrys to find INVALID 
> valid_group, and it will return the A to the add_depth_big function, so A's data is overridden.
> 

Not sure this message is entirely clear.
How about:
  When adding an entry to a tbl8, the .valid_group field should always be set,
  so that future adds do not accidently find and use this table, thinking it is
  currently invalid, i.e. unused, and thereby overwrite existing entries.

> Signed-off-by: NaNa <nana.nn@alibaba-inc.com>
> 
> ---
>  lib/librte_lpm/rte_lpm.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/lib/librte_lpm/rte_lpm.c b/lib/librte_lpm/rte_lpm.c
> index 57ec2f0..3981452 100644
> --- a/lib/librte_lpm/rte_lpm.c
> +++ b/lib/librte_lpm/rte_lpm.c
> @@ -769,6 +769,7 @@ delete_depth_small(struct rte_lpm *lpm, uint32_t ip_masked,
>  
>  		struct rte_lpm_tbl8_entry new_tbl8_entry = {
>  			.valid = VALID,
> +			.valid_group = VALID,
>  			.depth = sub_rule_depth,
>  			.next_hop = lpm->rules_tbl
>  			[sub_rule_index].next_hop,
> -- 
> 1.7.7.6
>