On Tue, Sep 22, 2020 at 03:46:57AM +0300, Vladimir Oltean wrote:
> From: Xiaoliang Yang <xiaoliang.yan...@nxp.com>
>
> There are 2 separate, but related, issues.
>
> First, the ocelot_vcap_block_get_filter_index function, née
> ocelot_ace_rule_get_index_id prior to the aae4e500e106 ("net: mscc:
> ocelot: generalize the "ACE/ACL" names") rename, does not do what the
> author probably intended. If the desired filter entry is not present in
> the ACL block, this function returns an index equal to the total number
> of filters, instead of -1, which is maybe what was intended, judging
> from the curious initialization with -1, and the "++index" idioms.
> Either way, none of the callers seems to expect this behavior.
>
> Second issue, the callers don't actually check the return value at all.
> So in case the filter is not found in the rule list, propagate the
> return code to avoid kernel panics.
>
> So update the callers and also take the opportunity to get rid of the
> odd coding idioms that appear to work but don't.
>
> Fixes: b596229448dd ("net: mscc: ocelot: Add support for tcam")
> Signed-off-by: Xiaoliang Yang <xiaoliang.yan...@nxp.com>
> Signed-off-by: Vladimir Oltean <vladimir.olt...@nxp.com>
> ---
> Changes in v2:
> Add Fixes tag.
>
> drivers/net/ethernet/mscc/ocelot_vcap.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/mscc/ocelot_vcap.c
> b/drivers/net/ethernet/mscc/ocelot_vcap.c
> index 3ef620faf995..39edaaca836e 100644
> --- a/drivers/net/ethernet/mscc/ocelot_vcap.c
> +++ b/drivers/net/ethernet/mscc/ocelot_vcap.c
> @@ -726,14 +726,15 @@ static int ocelot_vcap_block_get_filter_index(struct
> ocelot_vcap_block *block,
> struct ocelot_vcap_filter *filter)
> {
> struct ocelot_vcap_filter *tmp;
> - int index = -1;
> + int index = 0;
>
> list_for_each_entry(tmp, &block->rules, list) {
> - ++index;
> if (filter->id == tmp->id)
> break;
Please don't apply this. I meant to "return index" here instead of
leaving the "break". I'm not really sure what happened.
> + index++;
> }
> - return index;
> +
> + return -ENOENT;
> }
>
> static struct ocelot_vcap_filter*
> @@ -877,6 +878,8 @@ int ocelot_vcap_filter_add(struct ocelot *ocelot,
>
> /* Get the index of the inserted filter */
> index = ocelot_vcap_block_get_filter_index(block, filter);
> + if (index < 0)
> + return index;
>
> /* Move down the rules to make place for the new filter */
> for (i = block->count - 1; i > index; i--) {
> @@ -924,6 +927,8 @@ int ocelot_vcap_filter_del(struct ocelot *ocelot,
>
> /* Gets index of the filter */
> index = ocelot_vcap_block_get_filter_index(block, filter);
> + if (index < 0)
> + return index;
>
> /* Delete filter */
> ocelot_vcap_block_remove_filter(ocelot, block, filter);
> @@ -950,6 +955,9 @@ int ocelot_vcap_filter_stats_update(struct ocelot *ocelot,
> int index;
>
> index = ocelot_vcap_block_get_filter_index(block, filter);
> + if (index < 0)
> + return index;
> +
> is2_entry_get(ocelot, filter, index);
>
> /* After we get the result we need to clear the counters */
> --
> 2.25.1
>
Thanks,
-Vladimir
