mlxsw: spectrum_qdisc: Allocate child qdiscs dynamically

Instead of keeping qdiscs in globally-preallocated arrays, introduce a
per-qdisc-kind value num_classes, and then allocate the necessary child
qdiscs (if any) based on that value. Since now dynamic allocation is
involved, mlxsw_sp_qdisc_replace() gets messy enough that it is worth it to
split it to two cases: a new qdisc allocation and a change of existing
qdisc. (Note that the change also includes what TC formally calls replace,
if the qdisc kind is the same.)

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c
index 9e7f1a0..03c1310 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c
@@ -49,6 +49,7 @@ struct mlxsw_sp_qdisc_ops {
                          struct mlxsw_sp_qdisc *mlxsw_sp_qdisc, void *params);
        struct mlxsw_sp_qdisc *(*find_class)(struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
                                             u32 parent);
+       unsigned int num_classes;
 };
 
 struct mlxsw_sp_qdisc {
@@ -74,7 +75,6 @@ struct mlxsw_sp_qdisc {
 
 struct mlxsw_sp_qdisc_state {
        struct mlxsw_sp_qdisc root_qdisc;
-       struct mlxsw_sp_qdisc tclass_qdiscs[IEEE_8021QAZ_MAX_TCS];
 
        /* When a PRIO or ETS are added, the invisible FIFOs in their bands are
         * created first. When notifications for these FIFOs arrive, it is not
@@ -215,29 +215,41 @@ mlxsw_sp_qdisc_destroy(struct mlxsw_sp_port *mlxsw_sp_port,
        if (mlxsw_sp_qdisc->ops->destroy)
                err = mlxsw_sp_qdisc->ops->destroy(mlxsw_sp_port,
                                                   mlxsw_sp_qdisc);
+       if (mlxsw_sp_qdisc->ops->clean_stats)
+               mlxsw_sp_qdisc->ops->clean_stats(mlxsw_sp_port, mlxsw_sp_qdisc);
 
        mlxsw_sp_qdisc->handle = TC_H_UNSPEC;
        mlxsw_sp_qdisc->ops = NULL;
-
+       mlxsw_sp_qdisc->num_classes = 0;
+       kfree(mlxsw_sp_qdisc->qdiscs);
+       mlxsw_sp_qdisc->qdiscs = NULL;
        return err_hdroom ?: err;
 }
 
-static int
-mlxsw_sp_qdisc_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
-                      struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
-                      struct mlxsw_sp_qdisc_ops *ops, void *params)
+static int mlxsw_sp_qdisc_create(struct mlxsw_sp_port *mlxsw_sp_port,
+                                u32 handle,
+                                struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
+                                struct mlxsw_sp_qdisc_ops *ops, void *params)
 {
        struct mlxsw_sp_qdisc *root_qdisc = &mlxsw_sp_port->qdisc->root_qdisc;
        struct mlxsw_sp_hdroom orig_hdroom;
+       unsigned int i;
        int err;
 
-       if (mlxsw_sp_qdisc->ops && mlxsw_sp_qdisc->ops->type != ops->type)
-               /* In case this location contained a different qdisc of the
-                * same type we can override the old qdisc configuration.
-                * Otherwise, we need to remove the old qdisc before setting the
-                * new one.
-                */
-               mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
+       err = ops->check_params(mlxsw_sp_port, params);
+       if (err)
+               return err;
+
+       if (ops->num_classes) {
+               mlxsw_sp_qdisc->qdiscs = kcalloc(ops->num_classes,
+                                                sizeof(*mlxsw_sp_qdisc->qdiscs),
+                                                GFP_KERNEL);
+               if (!mlxsw_sp_qdisc->qdiscs)
+                       return -ENOMEM;
+
+               for (i = 0; i < ops->num_classes; i++)
+                       mlxsw_sp_qdisc->qdiscs[i].parent = mlxsw_sp_qdisc;
+       }
 
        orig_hdroom = *mlxsw_sp_port->hdroom;
        if (root_qdisc == mlxsw_sp_qdisc) {
@@ -253,20 +265,46 @@ mlxsw_sp_qdisc_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
                        goto err_hdroom_configure;
        }
 
+       mlxsw_sp_qdisc->num_classes = ops->num_classes;
+       mlxsw_sp_qdisc->ops = ops;
+       mlxsw_sp_qdisc->handle = handle;
+       err = ops->replace(mlxsw_sp_port, handle, mlxsw_sp_qdisc, params);
+       if (err)
+               goto err_replace;
+
+       return 0;
+
+err_replace:
+       mlxsw_sp_qdisc->handle = TC_H_UNSPEC;
+       mlxsw_sp_qdisc->ops = NULL;
+       mlxsw_sp_qdisc->num_classes = 0;
+       mlxsw_sp_hdroom_configure(mlxsw_sp_port, &orig_hdroom);
+err_hdroom_configure:
+       kfree(mlxsw_sp_qdisc->qdiscs);
+       mlxsw_sp_qdisc->qdiscs = NULL;
+       return err;
+}
+
+static int
+mlxsw_sp_qdisc_change(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
+                     struct mlxsw_sp_qdisc *mlxsw_sp_qdisc, void *params)
+{
+       struct mlxsw_sp_qdisc_ops *ops = mlxsw_sp_qdisc->ops;
+       int err;
+
        err = ops->check_params(mlxsw_sp_port, params);
        if (err)
-               goto err_bad_param;
+               goto unoffload;
 
        err = ops->replace(mlxsw_sp_port, handle, mlxsw_sp_qdisc, params);
        if (err)
-               goto err_config;
+               goto unoffload;
 
        /* Check if the Qdisc changed. That includes a situation where an
         * invisible Qdisc replaces another one, or is being added for the
         * first time.
         */
-       if (mlxsw_sp_qdisc->handle != handle || handle == TC_H_UNSPEC) {
-               mlxsw_sp_qdisc->ops = ops;
+       if (mlxsw_sp_qdisc->handle != handle) {
                if (ops->clean_stats)
                        ops->clean_stats(mlxsw_sp_port, mlxsw_sp_qdisc);
        }
@@ -274,11 +312,8 @@ mlxsw_sp_qdisc_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
        mlxsw_sp_qdisc->handle = handle;
        return 0;
 
-err_bad_param:
-err_config:
-       mlxsw_sp_hdroom_configure(mlxsw_sp_port, &orig_hdroom);
-err_hdroom_configure:
-       if (mlxsw_sp_qdisc->handle == handle && ops->unoffload)
+unoffload:
+       if (ops->unoffload)
                ops->unoffload(mlxsw_sp_port, mlxsw_sp_qdisc, params);
 
        mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
@@ -286,6 +321,27 @@ err_hdroom_configure:
 }
 
 static int
+mlxsw_sp_qdisc_replace(struct mlxsw_sp_port *mlxsw_sp_port, u32 handle,
+                      struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
+                      struct mlxsw_sp_qdisc_ops *ops, void *params)
+{
+       if (mlxsw_sp_qdisc->ops && mlxsw_sp_qdisc->ops->type != ops->type)
+               /* In case this location contained a different qdisc of the
+                * same type we can override the old qdisc configuration.
+                * Otherwise, we need to remove the old qdisc before setting the
+                * new one.
+                */
+               mlxsw_sp_qdisc_destroy(mlxsw_sp_port, mlxsw_sp_qdisc);
+
+       if (!mlxsw_sp_qdisc->ops)
+               return mlxsw_sp_qdisc_create(mlxsw_sp_port, handle,
+                                            mlxsw_sp_qdisc, ops, params);
+       else
+               return mlxsw_sp_qdisc_change(mlxsw_sp_port, handle,
+                                            mlxsw_sp_qdisc, params);
+}
+
+static int
 mlxsw_sp_qdisc_get_stats(struct mlxsw_sp_port *mlxsw_sp_port,
                         struct mlxsw_sp_qdisc *mlxsw_sp_qdisc,
                         struct tc_qopt_offload_stats *stats_ptr)
@@ -1049,6 +1105,9 @@ __mlxsw_sp_qdisc_ets_replace(struct mlxsw_sp_port *mlxsw_sp_port,
                                        return err;
                        }
                }
+
+               child_qdisc->tclass_num = tclass;
+
                if (old_priomap != child_qdisc->prio_bitmap &&
                    child_qdisc->ops && child_qdisc->ops->clean_stats) {
                        backlog = child_qdisc->stats_base.backlog;
@@ -1189,6 +1248,7 @@ static struct mlxsw_sp_qdisc_ops mlxsw_sp_qdisc_ops_prio = {
        .get_stats = mlxsw_sp_qdisc_get_prio_stats,
        .clean_stats = mlxsw_sp_setup_tc_qdisc_prio_clean_stats,
        .find_class = mlxsw_sp_qdisc_prio_find_class,
+       .num_classes = IEEE_8021QAZ_MAX_TCS,
 };
 
 static int
@@ -1239,6 +1299,7 @@ static struct mlxsw_sp_qdisc_ops mlxsw_sp_qdisc_ops_ets = {
        .get_stats = mlxsw_sp_qdisc_get_prio_stats,
        .clean_stats = mlxsw_sp_setup_tc_qdisc_prio_clean_stats,
        .find_class = mlxsw_sp_qdisc_prio_find_class,
+       .num_classes = IEEE_8021QAZ_MAX_TCS,
 };
 
 /* Linux allows linking of Qdiscs to arbitrary classes (so long as the resulting
@@ -1926,7 +1987,6 @@ int mlxsw_sp_setup_tc_block_qevent_early_drop(struct mlxsw_sp_port *mlxsw_sp_por
 int mlxsw_sp_tc_qdisc_init(struct mlxsw_sp_port *mlxsw_sp_port)
 {
        struct mlxsw_sp_qdisc_state *qdisc_state;
-       int i;
 
        qdisc_state = kzalloc(sizeof(*qdisc_state), GFP_KERNEL);
        if (!qdisc_state)
@@ -1935,15 +1995,6 @@ int mlxsw_sp_tc_qdisc_init(struct mlxsw_sp_port *mlxsw_sp_port)
        mutex_init(&qdisc_state->lock);
        qdisc_state->root_qdisc.prio_bitmap = 0xff;
        qdisc_state->root_qdisc.tclass_num = MLXSW_SP_PORT_DEFAULT_TCLASS;
-       qdisc_state->root_qdisc.qdiscs = qdisc_state->tclass_qdiscs;
-       qdisc_state->root_qdisc.num_classes = IEEE_8021QAZ_MAX_TCS;
-       for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
-               int tclass_num = MLXSW_SP_PRIO_BAND_TO_TCLASS(i);
-
-               qdisc_state->tclass_qdiscs[i].tclass_num = tclass_num;
-               qdisc_state->tclass_qdiscs[i].parent = &qdisc_state->root_qdisc;
-       }
-
        mlxsw_sp_port->qdisc = qdisc_state;
        return 0;
 }