Commit 0015b80a authored by Salvatore Mesoraca's avatar Salvatore Mesoraca Committed by David S. Miller
Browse files

net: dsa: Remove VLA usage 

We avoid 2 VLAs by using a pre-allocated field in dsa_switch. We also
try to avoid dynamic allocation whenever possible (when using fewer than
bits-per-long ports, which is the common case).

Link: http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Link: http://lkml.kernel.org/r/20180505185145.GB32630@lunn.ch


Signed-off-by: default avatarSalvatore Mesoraca <s.mesoraca16@gmail.com>
[kees: tweak commit subject and message slightly]
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 14260e91

include/net/dsa.h

+3 −0
Original line number Diff line number Diff line
@@ -259,6 +259,9 @@ struct dsa_switch { 
	/* Number of switch port queues */

	unsigned int		num_tx_queues;



	unsigned long		*bitmap;

	unsigned long		_bitmap;



	/* Dynamically allocated ports, keep last */

	size_t num_ports;

	struct dsa_port ports[];

net/dsa/dsa2.c

+14 −0
Original line number Diff line number Diff line
@@ -775,6 +775,20 @@ struct dsa_switch *dsa_switch_alloc(struct device *dev, size_t n) 
	if (!ds)

		return NULL;



	/* We avoid allocating memory outside dsa_switch

	 * if it is not needed.

	 */

	if (n <= sizeof(ds->_bitmap) * 8) {

		ds->bitmap = &ds->_bitmap;

	} else {

		ds->bitmap = devm_kcalloc(dev,

					  BITS_TO_LONGS(n),

					  sizeof(unsigned long),

					  GFP_KERNEL);

		if (unlikely(!ds->bitmap))

			return NULL;

	}



	ds->dev = dev;

	ds->num_ports = n;

net/dsa/switch.c

+10 −12
Original line number Diff line number Diff line
@@ -136,21 +136,20 @@ static int dsa_switch_mdb_add(struct dsa_switch *ds, 
{

	const struct switchdev_obj_port_mdb *mdb = info->mdb;

	struct switchdev_trans *trans = info->trans;

	DECLARE_BITMAP(group, ds->num_ports);

	int port;



	/* Build a mask of Multicast group members */

	bitmap_zero(group, ds->num_ports);

	bitmap_zero(ds->bitmap, ds->num_ports);

	if (ds->index == info->sw_index)

		set_bit(info->port, group);

		set_bit(info->port, ds->bitmap);

	for (port = 0; port < ds->num_ports; port++)

		if (dsa_is_dsa_port(ds, port))

			set_bit(port, group);

			set_bit(port, ds->bitmap);



	if (switchdev_trans_ph_prepare(trans))

		return dsa_switch_mdb_prepare_bitmap(ds, mdb, group);

		return dsa_switch_mdb_prepare_bitmap(ds, mdb, ds->bitmap);



	dsa_switch_mdb_add_bitmap(ds, mdb, group);

	dsa_switch_mdb_add_bitmap(ds, mdb, ds->bitmap);



	return 0;

}
@@ -204,21 +203,20 @@ static int dsa_switch_vlan_add(struct dsa_switch *ds, 
{

	const struct switchdev_obj_port_vlan *vlan = info->vlan;

	struct switchdev_trans *trans = info->trans;

	DECLARE_BITMAP(members, ds->num_ports);

	int port;



	/* Build a mask of VLAN members */

	bitmap_zero(members, ds->num_ports);

	bitmap_zero(ds->bitmap, ds->num_ports);

	if (ds->index == info->sw_index)

		set_bit(info->port, members);

		set_bit(info->port, ds->bitmap);

	for (port = 0; port < ds->num_ports; port++)

		if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))

			set_bit(port, members);

			set_bit(port, ds->bitmap);



	if (switchdev_trans_ph_prepare(trans))

		return dsa_switch_vlan_prepare_bitmap(ds, vlan, members);

		return dsa_switch_vlan_prepare_bitmap(ds, vlan, ds->bitmap);



	dsa_switch_vlan_add_bitmap(ds, vlan, members);

	dsa_switch_vlan_add_bitmap(ds, vlan, ds->bitmap);



	return 0;

}

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