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c7d03a00b5
Make struct pernet_operations::id unsigned.
There are 2 reasons to do so:
1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.
2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.
"int" being used as an array index needs to be sign-extended
to 64-bit before being used.
void f(long *p, int i)
{
g(p[i]);
}
roughly translates to
movsx rsi, esi
mov rdi, [rsi+...]
call g
MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.
Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:
static inline void *net_generic(const struct net *net, int id)
{
...
ptr = ng->ptr[id - 1];
...
}
And this function is used a lot, so those sign extensions add up.
Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]
However, overall balance is in negative direction:
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
function old new delta
nfsd4_lock 3886 3959 +73
tipc_link_build_proto_msg 1096 1140 +44
mac80211_hwsim_new_radio 2776 2808 +32
tipc_mon_rcv 1032 1058 +26
svcauth_gss_legacy_init 1413 1429 +16
tipc_bcbase_select_primary 379 392 +13
nfsd4_exchange_id 1247 1260 +13
nfsd4_setclientid_confirm 782 793 +11
...
put_client_renew_locked 494 480 -14
ip_set_sockfn_get 730 716 -14
geneve_sock_add 829 813 -16
nfsd4_sequence_done 721 703 -18
nlmclnt_lookup_host 708 686 -22
nfsd4_lockt 1085 1063 -22
nfs_get_client 1077 1050 -27
tcf_bpf_init 1106 1076 -30
nfsd4_encode_fattr 5997 5930 -67
Total: Before=154856051, After=154854321, chg -0.00%
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
176 lines
5.4 KiB
C
176 lines
5.4 KiB
C
#ifndef __BEN_VLAN_802_1Q_INC__
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#define __BEN_VLAN_802_1Q_INC__
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#include <linux/if_vlan.h>
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#include <linux/u64_stats_sync.h>
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#include <linux/list.h>
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/* if this changes, algorithm will have to be reworked because this
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* depends on completely exhausting the VLAN identifier space. Thus
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* it gives constant time look-up, but in many cases it wastes memory.
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*/
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#define VLAN_GROUP_ARRAY_SPLIT_PARTS 8
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#define VLAN_GROUP_ARRAY_PART_LEN (VLAN_N_VID/VLAN_GROUP_ARRAY_SPLIT_PARTS)
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enum vlan_protos {
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VLAN_PROTO_8021Q = 0,
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VLAN_PROTO_8021AD,
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VLAN_PROTO_NUM,
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};
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struct vlan_group {
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unsigned int nr_vlan_devs;
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struct hlist_node hlist; /* linked list */
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struct net_device **vlan_devices_arrays[VLAN_PROTO_NUM]
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[VLAN_GROUP_ARRAY_SPLIT_PARTS];
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};
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struct vlan_info {
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struct net_device *real_dev; /* The ethernet(like) device
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* the vlan is attached to.
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*/
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struct vlan_group grp;
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struct list_head vid_list;
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unsigned int nr_vids;
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struct rcu_head rcu;
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};
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static inline unsigned int vlan_proto_idx(__be16 proto)
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{
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switch (proto) {
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case htons(ETH_P_8021Q):
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return VLAN_PROTO_8021Q;
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case htons(ETH_P_8021AD):
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return VLAN_PROTO_8021AD;
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default:
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BUG();
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return 0;
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}
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}
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static inline struct net_device *__vlan_group_get_device(struct vlan_group *vg,
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unsigned int pidx,
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u16 vlan_id)
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{
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struct net_device **array;
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array = vg->vlan_devices_arrays[pidx]
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[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
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return array ? array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] : NULL;
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}
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static inline struct net_device *vlan_group_get_device(struct vlan_group *vg,
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__be16 vlan_proto,
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u16 vlan_id)
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{
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return __vlan_group_get_device(vg, vlan_proto_idx(vlan_proto), vlan_id);
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}
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static inline void vlan_group_set_device(struct vlan_group *vg,
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__be16 vlan_proto, u16 vlan_id,
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struct net_device *dev)
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{
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struct net_device **array;
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if (!vg)
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return;
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array = vg->vlan_devices_arrays[vlan_proto_idx(vlan_proto)]
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[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
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array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] = dev;
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}
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/* Must be invoked with rcu_read_lock or with RTNL. */
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static inline struct net_device *vlan_find_dev(struct net_device *real_dev,
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__be16 vlan_proto, u16 vlan_id)
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{
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struct vlan_info *vlan_info = rcu_dereference_rtnl(real_dev->vlan_info);
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if (vlan_info)
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return vlan_group_get_device(&vlan_info->grp,
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vlan_proto, vlan_id);
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return NULL;
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}
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#define vlan_group_for_each_dev(grp, i, dev) \
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for ((i) = 0; i < VLAN_PROTO_NUM * VLAN_N_VID; i++) \
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if (((dev) = __vlan_group_get_device((grp), (i) / VLAN_N_VID, \
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(i) % VLAN_N_VID)))
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/* found in vlan_dev.c */
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void vlan_dev_set_ingress_priority(const struct net_device *dev,
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u32 skb_prio, u16 vlan_prio);
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int vlan_dev_set_egress_priority(const struct net_device *dev,
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u32 skb_prio, u16 vlan_prio);
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int vlan_dev_change_flags(const struct net_device *dev, u32 flag, u32 mask);
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void vlan_dev_get_realdev_name(const struct net_device *dev, char *result);
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int vlan_check_real_dev(struct net_device *real_dev,
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__be16 protocol, u16 vlan_id);
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void vlan_setup(struct net_device *dev);
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int register_vlan_dev(struct net_device *dev);
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void unregister_vlan_dev(struct net_device *dev, struct list_head *head);
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bool vlan_dev_inherit_address(struct net_device *dev,
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struct net_device *real_dev);
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static inline u32 vlan_get_ingress_priority(struct net_device *dev,
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u16 vlan_tci)
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{
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struct vlan_dev_priv *vip = vlan_dev_priv(dev);
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return vip->ingress_priority_map[(vlan_tci >> VLAN_PRIO_SHIFT) & 0x7];
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}
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#ifdef CONFIG_VLAN_8021Q_GVRP
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int vlan_gvrp_request_join(const struct net_device *dev);
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void vlan_gvrp_request_leave(const struct net_device *dev);
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int vlan_gvrp_init_applicant(struct net_device *dev);
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void vlan_gvrp_uninit_applicant(struct net_device *dev);
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int vlan_gvrp_init(void);
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void vlan_gvrp_uninit(void);
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#else
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static inline int vlan_gvrp_request_join(const struct net_device *dev) { return 0; }
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static inline void vlan_gvrp_request_leave(const struct net_device *dev) {}
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static inline int vlan_gvrp_init_applicant(struct net_device *dev) { return 0; }
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static inline void vlan_gvrp_uninit_applicant(struct net_device *dev) {}
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static inline int vlan_gvrp_init(void) { return 0; }
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static inline void vlan_gvrp_uninit(void) {}
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#endif
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#ifdef CONFIG_VLAN_8021Q_MVRP
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int vlan_mvrp_request_join(const struct net_device *dev);
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void vlan_mvrp_request_leave(const struct net_device *dev);
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int vlan_mvrp_init_applicant(struct net_device *dev);
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void vlan_mvrp_uninit_applicant(struct net_device *dev);
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int vlan_mvrp_init(void);
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void vlan_mvrp_uninit(void);
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#else
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static inline int vlan_mvrp_request_join(const struct net_device *dev) { return 0; }
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static inline void vlan_mvrp_request_leave(const struct net_device *dev) {}
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static inline int vlan_mvrp_init_applicant(struct net_device *dev) { return 0; }
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static inline void vlan_mvrp_uninit_applicant(struct net_device *dev) {}
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static inline int vlan_mvrp_init(void) { return 0; }
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static inline void vlan_mvrp_uninit(void) {}
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#endif
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extern const char vlan_fullname[];
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extern const char vlan_version[];
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int vlan_netlink_init(void);
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void vlan_netlink_fini(void);
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extern struct rtnl_link_ops vlan_link_ops;
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extern unsigned int vlan_net_id;
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struct proc_dir_entry;
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struct vlan_net {
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/* /proc/net/vlan */
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struct proc_dir_entry *proc_vlan_dir;
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/* /proc/net/vlan/config */
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struct proc_dir_entry *proc_vlan_conf;
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/* Determines interface naming scheme. */
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unsigned short name_type;
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};
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#endif /* !(__BEN_VLAN_802_1Q_INC__) */
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