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alistair23-linux/fs/nfsd/netns.h

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/*
* per net namespace data structures for nfsd
*
* Copyright (C) 2012, Jeff Layton <jlayton@redhat.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef __NFSD_NETNS_H__
#define __NFSD_NETNS_H__
#include <net/net_namespace.h>
#include <net/netns/generic.h>
/* Hash tables for nfs4_clientid state */
#define CLIENT_HASH_BITS 4
#define CLIENT_HASH_SIZE (1 << CLIENT_HASH_BITS)
#define CLIENT_HASH_MASK (CLIENT_HASH_SIZE - 1)
#define SESSION_HASH_SIZE 512
struct cld_net;
struct nfsd4_client_tracking_ops;
/*
* Represents a nfsd "container". With respect to nfsv4 state tracking, the
* fields of interest are the *_id_hashtbls and the *_name_tree. These track
* the nfs4_client objects by either short or long form clientid.
*
* Each nfsd_net runs a nfs4_laundromat workqueue job when necessary to clean
* up expired clients and delegations within the container.
*/
struct nfsd_net {
struct cld_net *cld_net;
struct cache_detail *svc_expkey_cache;
struct cache_detail *svc_export_cache;
struct cache_detail *idtoname_cache;
struct cache_detail *nametoid_cache;
struct lock_manager nfsd4_manager;
bool grace_ended;
time_t boot_time;
/*
* reclaim_str_hashtbl[] holds known client info from previous reset/reboot
* used in reboot/reset lease grace period processing
*
* conf_id_hashtbl[], and conf_name_tree hold confirmed
* setclientid_confirmed info.
*
* unconf_str_hastbl[] and unconf_name_tree hold unconfirmed
* setclientid info.
*/
struct list_head *reclaim_str_hashtbl;
int reclaim_str_hashtbl_size;
struct list_head *conf_id_hashtbl;
struct rb_root conf_name_tree;
struct list_head *unconf_id_hashtbl;
struct rb_root unconf_name_tree;
struct list_head *sessionid_hashtbl;
/*
* client_lru holds client queue ordered by nfs4_client.cl_time
* for lease renewal.
*
* close_lru holds (open) stateowner queue ordered by nfs4_stateowner.so_time
* for last close replay.
*
* All of the above fields are protected by the client_mutex.
*/
struct list_head client_lru;
struct list_head close_lru;
struct list_head del_recall_lru;
/* protected by blocked_locks_lock */
struct list_head blocked_locks_lru;
struct delayed_work laundromat_work;
/* client_lock protects the client lru list and session hash table */
spinlock_t client_lock;
/* protects blocked_locks_lru */
spinlock_t blocked_locks_lock;
struct file *rec_file;
bool in_grace;
const struct nfsd4_client_tracking_ops *client_tracking_ops;
time_t nfsd4_lease;
time_t nfsd4_grace;
bool somebody_reclaimed;
bool nfsd_net_up;
bool lockd_up;
/* Time of server startup */
struct timespec64 nfssvc_boot;
/*
* Max number of connections this nfsd container will allow. Defaults
* to '0' which is means that it bases this on the number of threads.
*/
unsigned int max_connections;
u32 clientid_counter;
u32 clverifier_counter;
struct svc_serv *nfsd_serv;
wait_queue_head_t ntf_wq;
atomic_t ntf_refcnt;
/*
* clientid and stateid data for construction of net unique COPY
* stateids.
*/
u32 s2s_cp_cl_id;
struct idr s2s_cp_stateids;
spinlock_t s2s_cp_lock;
};
/* Simple check to find out if a given net was properly initialized */
#define nfsd_netns_ready(nn) ((nn)->sessionid_hashtbl)
netns: make struct pernet_operations::id unsigned int 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>
2016-11-16 18:58:21 -07:00
extern unsigned int nfsd_net_id;
#endif /* __NFSD_NETNS_H__ */