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Date: Mon, 7 May 2018 17:23:16 +0200
From: Salvatore Mesoraca <s.mesoraca16@...il.com>
To: Andrew Lunn <andrew@...n.ch>
Cc: linux-kernel@...r.kernel.org,
kernel-hardening@...ts.openwall.com,
netdev@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
Florian Fainelli <f.fainelli@...il.com>,
Kees Cook <keescook@...omium.org>,
Salvatore Mesoraca <s.mesoraca16@...il.com>,
Vivien Didelot <vivien.didelot@...oirfairelinux.com>,
David Laight <David.Laight@...LAB.COM>
Subject: [PATCH v2] net: dsa: drop some VLAs in switch.c
We avoid 2 VLAs by using a pre-allocated field in dsa_switch.
We also try to avoid dynamic allocation whenever possible.
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: Salvatore Mesoraca <s.mesoraca16@...il.com>
---
include/net/dsa.h | 3 +++
net/dsa/dsa2.c | 14 ++++++++++++++
net/dsa/switch.c | 22 ++++++++++------------
3 files changed, 27 insertions(+), 12 deletions(-)
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 60fb4ec..576791d 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -256,6 +256,9 @@ 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[];
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index adf50fb..cebf35f0 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -748,6 +748,20 @@ 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_kzalloc(dev,
+ BITS_TO_LONGS(n) *
+ sizeof(unsigned long),
+ GFP_KERNEL);
+ if (unlikely(!ds->bitmap))
+ return NULL;
+ }
+
ds->dev = dev;
ds->num_ports = n;
diff --git a/net/dsa/switch.c b/net/dsa/switch.c
index b935117..142b294 100644
--- a/net/dsa/switch.c
+++ b/net/dsa/switch.c
@@ -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;
}
--
1.9.1
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