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mlxsw: spectrum_router: Avoid potential packets loss
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When the structure of the LPM tree changes (f.e., due to the addition of
a new prefix), we unbind the old tree and then bind the new one. This
may result in temporary packet loss.

Instead, overwrite the old binding with the new one.

Fixes: 6b75c48 ("mlxsw: spectrum_router: Add virtual router management")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Ido Schimmel authored and David S. Miller committed Mar 1, 2017
1 parent 4f7bfb3 commit f7df492
Showing 1 changed file with 20 additions and 10 deletions.
30 changes: 20 additions & 10 deletions drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
Original file line number Diff line number Diff line change
Expand Up @@ -441,30 +441,40 @@ static int
mlxsw_sp_vr_lpm_tree_check(struct mlxsw_sp *mlxsw_sp, struct mlxsw_sp_vr *vr,
struct mlxsw_sp_prefix_usage *req_prefix_usage)
{
struct mlxsw_sp_lpm_tree *lpm_tree;
struct mlxsw_sp_lpm_tree *lpm_tree = vr->lpm_tree;
struct mlxsw_sp_lpm_tree *new_tree;
int err;

if (mlxsw_sp_prefix_usage_eq(req_prefix_usage,
&vr->lpm_tree->prefix_usage))
if (mlxsw_sp_prefix_usage_eq(req_prefix_usage, &lpm_tree->prefix_usage))
return 0;

lpm_tree = mlxsw_sp_lpm_tree_get(mlxsw_sp, req_prefix_usage,
new_tree = mlxsw_sp_lpm_tree_get(mlxsw_sp, req_prefix_usage,
vr->proto, false);
if (IS_ERR(lpm_tree)) {
if (IS_ERR(new_tree)) {
/* We failed to get a tree according to the required
* prefix usage. However, the current tree might be still good
* for us if our requirement is subset of the prefixes used
* in the tree.
*/
if (mlxsw_sp_prefix_usage_subset(req_prefix_usage,
&vr->lpm_tree->prefix_usage))
&lpm_tree->prefix_usage))
return 0;
return PTR_ERR(lpm_tree);
return PTR_ERR(new_tree);
}

mlxsw_sp_vr_lpm_tree_unbind(mlxsw_sp, vr);
mlxsw_sp_lpm_tree_put(mlxsw_sp, vr->lpm_tree);
/* Prevent packet loss by overwriting existing binding */
vr->lpm_tree = new_tree;
err = mlxsw_sp_vr_lpm_tree_bind(mlxsw_sp, vr);
if (err)
goto err_tree_bind;
mlxsw_sp_lpm_tree_put(mlxsw_sp, lpm_tree);

return 0;

err_tree_bind:
vr->lpm_tree = lpm_tree;
return mlxsw_sp_vr_lpm_tree_bind(mlxsw_sp, vr);
mlxsw_sp_lpm_tree_put(mlxsw_sp, new_tree);
return err;
}

static struct mlxsw_sp_vr *mlxsw_sp_vr_get(struct mlxsw_sp *mlxsw_sp,
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