The next_id object-allocation functionality was introduced in 03f595668017f (ipc: add sysctl to specify desired next object id). Given that these new entries are _only_ exported under the CONFIG_CHECKPOINT_RESTORE option, there is no point for the common case to even know about ->next_id. As such rewrite ipc_buildid() such that it can do away with the field as well as unnecessary branches when adding a new identifier. The end result also better differentiates both cases, so the code ends up being cleaner; albeit the small duplications regarding the default case.
Signed-off-by: Davidlohr Bueso <[email protected]> --- include/linux/ipc_namespace.h | 2 ++ ipc/util.c | 60 ++++++++++++++++++++++++++++++++----------- ipc/util.h | 5 ---- 3 files changed, 47 insertions(+), 20 deletions(-) diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h index 83f0bf7a587d..058051566ced 100644 --- a/include/linux/ipc_namespace.h +++ b/include/linux/ipc_namespace.h @@ -18,7 +18,9 @@ struct ipc_ids { bool tables_initialized; struct rw_semaphore rwsem; struct idr ipcs_idr; +#ifdef CONFIG_CHECKPOINT_RESTORE int next_id; +#endif struct rhashtable key_ht; }; diff --git a/ipc/util.c b/ipc/util.c index 78755873cc5b..fb69152705e6 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -115,13 +115,15 @@ int ipc_init_ids(struct ipc_ids *ids) int err; ids->in_use = 0; ids->seq = 0; - ids->next_id = -1; init_rwsem(&ids->rwsem); err = rhashtable_init(&ids->key_ht, &ipc_kht_params); if (err) return err; idr_init(&ids->ipcs_idr); ids->tables_initialized = true; +#ifdef CONFIG_CHECKPOINT_RESTORE + ids->next_id = -1; +#endif return 0; } @@ -215,6 +217,46 @@ int ipc_get_maxid(struct ipc_ids *ids) return max_id; } +#ifdef CONFIG_CHECKPOINT_RESTORE +/* + * Specify desired id for next allocated IPC object. + */ +#define ipc_idr_alloc(ids, new) \ + idr_alloc(&(ids)->ipcs_idr, (new), \ + (ids)->next_id < 0 ? 0: ipcid_to_idx((ids)->next_id), \ + 0, GFP_NOWAIT); + +static inline int ipc_buildid(int id, struct ipc_ids *ids, + struct kern_ipc_perm *new) +{ + if (ids->next_id < 0) { /* default, behave as !CHECKPOINT_RESTORE */ + new->seq = ids->seq++; + if (ids->seq > IPCID_SEQ_MAX) + ids->seq = 0; + } else { + new->seq = ipcid_to_seqx(ids->next_id); + ids->next_id = -1; + } + + return SEQ_MULTIPLIER * new->seq + id; +} + +#else +#define ipc_idr_alloc(ids, new) \ + idr_alloc(&(ids)->ipcs_idr, (new), 0, 0, GFP_NOWAIT); + +static inline int ipc_buildid(int id, struct ipc_ids *ids, + struct kern_ipc_perm *new) +{ + new->seq = ids->seq++; + if (ids->seq > IPCID_SEQ_MAX) + ids->seq = 0; + + return SEQ_MULTIPLIER * new->seq + id; +} + +#endif /* CONFIG_CHECKPOINT_RESTORE */ + /** * ipc_addid - add an ipc identifier * @ids: ipc identifier set @@ -233,7 +275,6 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) kuid_t euid; kgid_t egid; int id, err; - int next_id = ids->next_id; if (size > IPCMNI) size = IPCMNI; @@ -253,9 +294,7 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) new->cuid = new->uid = euid; new->gid = new->cgid = egid; - id = idr_alloc(&ids->ipcs_idr, new, - (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, - GFP_NOWAIT); + id = ipc_idr_alloc(ids, new); idr_preload_end(); if (id >= 0 && new->key != IPC_PRIVATE) { @@ -273,17 +312,8 @@ int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) } ids->in_use++; + new->id = ipc_buildid(id, ids, new); - if (next_id < 0) { - new->seq = ids->seq++; - if (ids->seq > IPCID_SEQ_MAX) - ids->seq = 0; - } else { - new->seq = ipcid_to_seqx(next_id); - ids->next_id = -1; - } - - new->id = ipc_buildid(id, new->seq); return id; } diff --git a/ipc/util.h b/ipc/util.h index 80c9f51c3f07..17c8d2f14990 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -145,11 +145,6 @@ extern struct msg_msg *load_msg(const void __user *src, size_t len); extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); -static inline int ipc_buildid(int id, int seq) -{ - return SEQ_MULTIPLIER * seq + id; -} - static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) { return uid / SEQ_MULTIPLIER != ipcp->seq; -- 2.12.0
