diff options
Diffstat (limited to 'ipc/sem.c')
| -rw-r--r-- | ipc/sem.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index 227948f28ce..5215a81420d 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -90,6 +90,52 @@ #include <asm/uaccess.h> #include "util.h" +/* One semaphore structure for each semaphore in the system. */ +struct sem { + int semval; /* current value */ + int sempid; /* pid of last operation */ + struct list_head sem_pending; /* pending single-sop operations */ +}; + +/* One queue for each sleeping process in the system. */ +struct sem_queue { + struct list_head simple_list; /* queue of pending operations */ + struct list_head list; /* queue of pending operations */ + struct task_struct *sleeper; /* this process */ + struct sem_undo *undo; /* undo structure */ + int pid; /* process id of requesting process */ + int status; /* completion status of operation */ + struct sembuf *sops; /* array of pending operations */ + int nsops; /* number of operations */ + int alter; /* does *sops alter the array? */ +}; + +/* Each task has a list of undo requests. They are executed automatically + * when the process exits. + */ +struct sem_undo { + struct list_head list_proc; /* per-process list: * + * all undos from one process + * rcu protected */ + struct rcu_head rcu; /* rcu struct for sem_undo */ + struct sem_undo_list *ulp; /* back ptr to sem_undo_list */ + struct list_head list_id; /* per semaphore array list: + * all undos for one array */ + int semid; /* semaphore set identifier */ + short *semadj; /* array of adjustments */ + /* one per semaphore */ +}; + +/* sem_undo_list controls shared access to the list of sem_undo structures + * that may be shared among all a CLONE_SYSVSEM task group. + */ +struct sem_undo_list { + atomic_t refcnt; + spinlock_t lock; + struct list_head list_proc; +}; + + #define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS]) #define sem_unlock(sma) ipc_unlock(&(sma)->sem_perm) |