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vlan: Avoid hash table lookup to find group.
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A struct net_device always maps to zero or one vlan groups and we
always know the device when we are looking up a group.  We currently
do a hash table lookup on the device to find the group but it is
much simpler to just store a pointer.

Signed-off-by: Jesse Gross <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@jessegross @davem330
jessegross authored and davem330 committed Oct 21, 2010
1 parent 7b9c609 commit 65ac6a5
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Showing 5 changed files with 34 additions and 73 deletions.
19 changes: 19 additions & 0 deletions include/linux/if_vlan.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
#ifdef __KERNEL__
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>

#define VLAN_HLEN 4 /* The additional bytes (on top of the Ethernet header)
* that VLAN requires.
Expand Down Expand Up @@ -114,6 +115,18 @@ static inline void vlan_group_set_device(struct vlan_group *vg,
#define vlan_tx_tag_get(__skb) ((__skb)->vlan_tci & ~VLAN_TAG_PRESENT)

#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
/* Must be invoked with rcu_read_lock or with RTNL. */
static inline struct net_device *vlan_find_dev(struct net_device *real_dev,
u16 vlan_id)
{
struct vlan_group *grp = rcu_dereference_rtnl(real_dev->vlgrp);

if (grp)
return vlan_group_get_device(grp, vlan_id);

return NULL;
}

extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
extern u16 vlan_dev_vlan_id(const struct net_device *dev);

Expand All @@ -128,6 +141,12 @@ vlan_gro_frags(struct napi_struct *napi, struct vlan_group *grp,
unsigned int vlan_tci);

#else
static inline struct net_device *vlan_find_dev(struct net_device *real_dev,
u16 vlan_id)
{
return NULL;
}

static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
{
BUG();
Expand Down
5 changes: 4 additions & 1 deletion include/linux/netdevice.h
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Original file line number Diff line number Diff line change
Expand Up @@ -942,7 +942,10 @@ struct net_device {


/* Protocol specific pointers */


#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
struct vlan_group *vlgrp; /* VLAN group */
#endif
#ifdef CONFIG_NET_DSA
void *dsa_ptr; /* dsa specific data */
#endif
Expand Down
64 changes: 10 additions & 54 deletions net/8021q/vlan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -44,9 +44,6 @@

int vlan_net_id __read_mostly;

/* Our listing of VLAN group(s) */
static struct hlist_head vlan_group_hash[VLAN_GRP_HASH_SIZE];

const char vlan_fullname[] = "802.1Q VLAN Support";
const char vlan_version[] = DRV_VERSION;
static const char vlan_copyright[] = "Ben Greear <[email protected]>";
Expand All @@ -59,40 +56,6 @@ static struct packet_type vlan_packet_type __read_mostly = {

/* End of global variables definitions. */

static inline unsigned int vlan_grp_hashfn(unsigned int idx)
{
return ((idx >> VLAN_GRP_HASH_SHIFT) ^ idx) & VLAN_GRP_HASH_MASK;
}

/* Must be invoked with RCU read lock (no preempt) */
static struct vlan_group *__vlan_find_group(struct net_device *real_dev)
{
struct vlan_group *grp;
struct hlist_node *n;
int hash = vlan_grp_hashfn(real_dev->ifindex);

hlist_for_each_entry_rcu(grp, n, &vlan_group_hash[hash], hlist) {
if (grp->real_dev == real_dev)
return grp;
}

return NULL;
}

/* Find the protocol handler. Assumes VID < VLAN_VID_MASK.
*
* Must be invoked with RCU read lock (no preempt)
*/
struct net_device *__find_vlan_dev(struct net_device *real_dev, u16 vlan_id)
{
struct vlan_group *grp = __vlan_find_group(real_dev);

if (grp)
return vlan_group_get_device(grp, vlan_id);

return NULL;
}

static void vlan_group_free(struct vlan_group *grp)
{
int i;
Expand All @@ -111,8 +74,6 @@ static struct vlan_group *vlan_group_alloc(struct net_device *real_dev)
return NULL;

grp->real_dev = real_dev;
hlist_add_head_rcu(&grp->hlist,
&vlan_group_hash[vlan_grp_hashfn(real_dev->ifindex)]);
return grp;
}

Expand Down Expand Up @@ -151,7 +112,7 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head)

ASSERT_RTNL();

grp = __vlan_find_group(real_dev);
grp = real_dev->vlgrp;
BUG_ON(!grp);

/* Take it out of our own structures, but be sure to interlock with
Expand All @@ -173,11 +134,10 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head)
if (grp->nr_vlans == 0) {
vlan_gvrp_uninit_applicant(real_dev);

rcu_assign_pointer(real_dev->vlgrp, NULL);
if (real_dev->features & NETIF_F_HW_VLAN_RX)
ops->ndo_vlan_rx_register(real_dev, NULL);

hlist_del_rcu(&grp->hlist);

/* Free the group, after all cpu's are done. */
call_rcu(&grp->rcu, vlan_rcu_free);
}
Expand Down Expand Up @@ -207,7 +167,7 @@ int vlan_check_real_dev(struct net_device *real_dev, u16 vlan_id)
return -EOPNOTSUPP;
}

if (__find_vlan_dev(real_dev, vlan_id) != NULL)
if (vlan_find_dev(real_dev, vlan_id) != NULL)
return -EEXIST;

return 0;
Expand All @@ -222,7 +182,7 @@ int register_vlan_dev(struct net_device *dev)
struct vlan_group *grp, *ngrp = NULL;
int err;

grp = __vlan_find_group(real_dev);
grp = real_dev->vlgrp;
if (!grp) {
ngrp = grp = vlan_group_alloc(real_dev);
if (!grp)
Expand Down Expand Up @@ -252,8 +212,11 @@ int register_vlan_dev(struct net_device *dev)
vlan_group_set_device(grp, vlan_id, dev);
grp->nr_vlans++;

if (ngrp && real_dev->features & NETIF_F_HW_VLAN_RX)
ops->ndo_vlan_rx_register(real_dev, ngrp);
if (ngrp) {
if (real_dev->features & NETIF_F_HW_VLAN_RX)
ops->ndo_vlan_rx_register(real_dev, ngrp);
rcu_assign_pointer(real_dev->vlgrp, ngrp);
}
if (real_dev->features & NETIF_F_HW_VLAN_FILTER)
ops->ndo_vlan_rx_add_vid(real_dev, vlan_id);

Expand All @@ -264,7 +227,6 @@ int register_vlan_dev(struct net_device *dev)
vlan_gvrp_uninit_applicant(real_dev);
out_free_group:
if (ngrp) {
hlist_del_rcu(&ngrp->hlist);
/* Free the group, after all cpu's are done. */
call_rcu(&ngrp->rcu, vlan_rcu_free);
}
Expand Down Expand Up @@ -428,7 +390,7 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event,
dev->netdev_ops->ndo_vlan_rx_add_vid(dev, 0);
}

grp = __vlan_find_group(dev);
grp = dev->vlgrp;
if (!grp)
goto out;

Expand Down Expand Up @@ -746,19 +708,13 @@ static int __init vlan_proto_init(void)

static void __exit vlan_cleanup_module(void)
{
unsigned int i;

vlan_ioctl_set(NULL);
vlan_netlink_fini();

unregister_netdevice_notifier(&vlan_notifier_block);

dev_remove_pack(&vlan_packet_type);

/* This table must be empty if there are no module references left. */
for (i = 0; i < VLAN_GRP_HASH_SIZE; i++)
BUG_ON(!hlist_empty(&vlan_group_hash[i]));

unregister_pernet_subsys(&vlan_net_ops);
rcu_barrier(); /* Wait for completion of call_rcu()'s */

Expand Down
17 changes: 0 additions & 17 deletions net/8021q/vlan.h
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Original file line number Diff line number Diff line change
Expand Up @@ -72,23 +72,6 @@ static inline struct vlan_dev_info *vlan_dev_info(const struct net_device *dev)
return netdev_priv(dev);
}

#define VLAN_GRP_HASH_SHIFT 5
#define VLAN_GRP_HASH_SIZE (1 << VLAN_GRP_HASH_SHIFT)
#define VLAN_GRP_HASH_MASK (VLAN_GRP_HASH_SIZE - 1)

/* Find a VLAN device by the MAC address of its Ethernet device, and
* it's VLAN ID. The default configuration is to have VLAN's scope
* to be box-wide, so the MAC will be ignored. The mac will only be
* looked at if we are configured to have a separate set of VLANs per
* each MAC addressable interface. Note that this latter option does
* NOT follow the spec for VLANs, but may be useful for doing very
* large quantities of VLAN MUX/DEMUX onto FrameRelay or ATM PVCs.
*
* Must be invoked with rcu_read_lock (ie preempt disabled)
* or with RTNL.
*/
struct net_device *__find_vlan_dev(struct net_device *real_dev, u16 vlan_id);

/* found in vlan_dev.c */
int vlan_skb_recv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *ptype, struct net_device *orig_dev);
Expand Down
2 changes: 1 addition & 1 deletion net/8021q/vlan_dev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -158,7 +158,7 @@ int vlan_skb_recv(struct sk_buff *skb, struct net_device *dev,
vlan_id = vlan_tci & VLAN_VID_MASK;

rcu_read_lock();
vlan_dev = __find_vlan_dev(dev, vlan_id);
vlan_dev = vlan_find_dev(dev, vlan_id);

/* If the VLAN device is defined, we use it.
* If not, and the VID is 0, it is a 802.1p packet (not
Expand Down

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