diff options
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/sem.c | 65 |
1 files changed, 34 insertions, 31 deletions
@@ -99,7 +99,6 @@ struct sem { /* 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 */ @@ -519,7 +518,7 @@ static void wake_up_sem_queue_prepare(struct list_head *pt, q->status = IN_WAKEUP; q->pid = error; - list_add_tail(&q->simple_list, pt); + list_add_tail(&q->list, pt); } /** @@ -537,7 +536,7 @@ static void wake_up_sem_queue_do(struct list_head *pt) int did_something; did_something = !list_empty(pt); - list_for_each_entry_safe(q, t, pt, simple_list) { + list_for_each_entry_safe(q, t, pt, list) { wake_up_process(q->sleeper); /* q can disappear immediately after writing q->status. */ smp_wmb(); @@ -550,9 +549,7 @@ static void wake_up_sem_queue_do(struct list_head *pt) static void unlink_queue(struct sem_array *sma, struct sem_queue *q) { list_del(&q->list); - if (q->nsops == 1) - list_del(&q->simple_list); - else + if (q->nsops > 1) sma->complex_count--; } @@ -605,9 +602,9 @@ static int check_restart(struct sem_array *sma, struct sem_queue *q) } /* * semval is 0. Check if there are wait-for-zero semops. - * They must be the first entries in the per-semaphore simple queue + * They must be the first entries in the per-semaphore queue */ - h = list_first_entry(&curr->sem_pending, struct sem_queue, simple_list); + h = list_first_entry(&curr->sem_pending, struct sem_queue, list); BUG_ON(h->nsops != 1); BUG_ON(h->sops[0].sem_num != q->sops[0].sem_num); @@ -627,8 +624,9 @@ static int check_restart(struct sem_array *sma, struct sem_queue *q) * @pt: list head for the tasks that must be woken up. * * update_queue must be called after a semaphore in a semaphore array - * was modified. If multiple semaphore were modified, then @semnum - * must be set to -1. + * was modified. If multiple semaphores were modified, update_queue must + * be called with semnum = -1, as well as with the number of each modified + * semaphore. * The tasks that must be woken up are added to @pt. The return code * is stored in q->pid. * The function return 1 if at least one semop was completed successfully. @@ -638,30 +636,19 @@ static int update_queue(struct sem_array *sma, int semnum, struct list_head *pt) struct sem_queue *q; struct list_head *walk; struct list_head *pending_list; - int offset; int semop_completed = 0; - /* if there are complex operations around, then knowing the semaphore - * that was modified doesn't help us. Assume that multiple semaphores - * were modified. - */ - if (sma->complex_count) - semnum = -1; - - if (semnum == -1) { + if (semnum == -1) pending_list = &sma->sem_pending; - offset = offsetof(struct sem_queue, list); - } else { + else pending_list = &sma->sem_base[semnum].sem_pending; - offset = offsetof(struct sem_queue, simple_list); - } again: walk = pending_list->next; while (walk != pending_list) { int error, restart; - q = (struct sem_queue *)((char *)walk - offset); + q = container_of(walk, struct sem_queue, list); walk = walk->next; /* If we are scanning the single sop, per-semaphore list of @@ -720,9 +707,18 @@ static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsop if (sma->complex_count || sops == NULL) { if (update_queue(sma, -1, pt)) otime = 1; + } + + if (!sops) { + /* No semops; something special is going on. */ + for (i = 0; i < sma->sem_nsems; i++) { + if (update_queue(sma, i, pt)) + otime = 1; + } goto done; } + /* Check the semaphores that were modified. */ for (i = 0; i < nsops; i++) { if (sops[i].sem_op > 0 || (sops[i].sem_op < 0 && @@ -793,6 +789,7 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) struct sem_queue *q, *tq; struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm); struct list_head tasks; + int i; /* Free the existing undo structures for this semaphore set. */ assert_spin_locked(&sma->sem_perm.lock); @@ -811,6 +808,13 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) unlink_queue(sma, q); wake_up_sem_queue_prepare(&tasks, q, -EIDRM); } + for (i = 0; i < sma->sem_nsems; i++) { + struct sem *sem = sma->sem_base + i; + list_for_each_entry_safe(q, tq, &sem->sem_pending, list) { + unlink_queue(sma, q); + wake_up_sem_queue_prepare(&tasks, q, -EIDRM); + } + } /* Remove the semaphore set from the IDR */ sem_rmid(ns, sma); @@ -1565,21 +1569,20 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, queue.undo = un; queue.pid = task_tgid_vnr(current); queue.alter = alter; - if (alter) - list_add_tail(&queue.list, &sma->sem_pending); - else - list_add(&queue.list, &sma->sem_pending); if (nsops == 1) { struct sem *curr; curr = &sma->sem_base[sops->sem_num]; if (alter) - list_add_tail(&queue.simple_list, &curr->sem_pending); + list_add_tail(&queue.list, &curr->sem_pending); else - list_add(&queue.simple_list, &curr->sem_pending); + list_add(&queue.list, &curr->sem_pending); } else { - INIT_LIST_HEAD(&queue.simple_list); + if (alter) + list_add_tail(&queue.list, &sma->sem_pending); + else + list_add(&queue.list, &sma->sem_pending); sma->complex_count++; } |
