Re: [PATCH v2 1/2] lib/lpm:fix an issue of condition check in delete_depth_small()

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

On Fri, Oct 30, 2015 at 09:14:38PM +0800, Jijiang Liu wrote:
> Fixes an issue of check logic in delete_depth_small function.
> 
> For a tbl24 entry, the 'ext_entry' field indicates whether we need to use tbl8_gindex to read the next_hop from a tbl8 entry, or whether it can be read directly from this entry.
> 
> If a route is deleted, the prefix of previous route is used to override the deleted route.
> 
> When checking the depth of the previous route the conditional checks both the ext_entry and the depth, but the "else" leg fails to take account that the condition could fail for one of two possible reasons, leading to an incorrect flow when 'ext_entry == 0' is true , but 'lpm->tbl24[i].depth > depth' is false. The fix here is to add a condition check to the else leg so that it only executes when ext_entry is set.
> 
> Signed-off-by: NaNa <nana.nn@alibaba-inc.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>