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Message-ID: <CAGXu5j+Xyb0hD5iMqQHKaGdjBx2TftwU8kNgOT_rKswLsc2=qg@mail.gmail.com>
Date: Tue, 19 Jun 2018 21:43:20 -0700
From: Kees Cook <keescook@...omium.org>
To: Salvatore Mesoraca <s.mesoraca16@...il.com>
Cc: Andrew Lunn <andrew@...n.ch>, LKML <linux-kernel@...r.kernel.org>,
Kernel Hardening <kernel-hardening@...ts.openwall.com>,
Network Development <netdev@...r.kernel.org>, "David S. Miller" <davem@...emloft.net>,
Florian Fainelli <f.fainelli@...il.com>, Vivien Didelot <vivien.didelot@...oirfairelinux.com>,
David Laight <David.Laight@...lab.com>
Subject: Re: [PATCH v2] net: dsa: drop some VLAs in switch.c
On Mon, May 7, 2018 at 8:23 AM, Salvatore Mesoraca
<s.mesoraca16@...il.com> wrote:
> 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>
Friendly ping. What's needed to take this into the tree? It looks like
all the issues in v1 were addressed here.
Thanks!
-Kees
> ---
> 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
>
--
Kees Cook
Pixel Security
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