diff options
Diffstat (limited to 'include/linux/sem.h')
| -rw-r--r-- | include/linux/sem.h | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/include/linux/sem.h b/include/linux/sem.h index 9edec926e9d9..be5cf2ea14ad 100644 --- a/include/linux/sem.h +++ b/include/linux/sem.h @@ -8,11 +8,29 @@ struct task_struct; +/* One semaphore structure for each semaphore in the system. */ +struct sem { + int semval; /* current value */ + /* + * PID of the process that last modified the semaphore. For + * Linux, specifically these are: + * - semop + * - semctl, via SETVAL and SETALL. + * - at task exit when performing undo adjustments (see exit_sem). + */ + int sempid; + spinlock_t lock; /* spinlock for fine-grained semtimedop */ + struct list_head pending_alter; /* pending single-sop operations */ + /* that alter the semaphore */ + struct list_head pending_const; /* pending single-sop operations */ + /* that do not alter the semaphore*/ + time_t sem_otime; /* candidate for sem_otime */ +} ____cacheline_aligned_in_smp; + /* One sem_array data structure for each set of semaphores in the system. */ struct sem_array { struct kern_ipc_perm sem_perm; /* permissions .. see ipc.h */ - time_t sem_ctime; /* last change time */ - struct sem *sem_base; /* ptr to first semaphore in array */ + time_t sem_ctime; /* create/last semctl() time */ struct list_head pending_alter; /* pending operations */ /* that alter the array */ struct list_head pending_const; /* pending complex operations */ @@ -21,6 +39,8 @@ struct sem_array { int sem_nsems; /* no. of semaphores in array */ int complex_count; /* pending complex operations */ unsigned int use_global_lock;/* >0: global lock required */ + + struct sem sems[]; }; #ifdef CONFIG_SYSVIPC |